CLASSIFICATION OF DATA One of the principal values of vital statistics data is realized through the presentation of rates that are computed by relating the vital events of a class to the population of a similarly defined class. Vital statistics and population statistics, therefore, must be classified according to similarly defined systems and tabulated in comparable groups. Even when the variables common to both, such as geographic area, age, race, and sex, have been similarly classified and tabulated, differences between the enumeration method of obtaining population data and the registration method of obtaining vital statistics data may result in significant discrepancies. The general rules used to classify geographic and personal items for live births are set forth in "Vital Statistics Classification and Coding Instructions for Live Birth Records, 1994," NCHS Instruction Manual, Part 3a. The classification of certain important items is discussed in the following pages. Classification by occurrence and residence All but three tabulations for States and other areas within the United States are by place of mother's residence. These three tables (1-26, 1-27, and 2-1) show births by place of occurrence. Births to U.S. residents occurring outside this country are not reallocated to the United States. In tabulations by place of residence, births occurring within the United States to U.S. citizens and to resident aliens are allocated to the usual place of residence of the mother in the United States, as reported on the birth certificate. Beginning in 1970 births to nonresidents of the United States occurring in the United States are excluded from these tabulations. From 1966 to 1969 births occurring in the United States to mothers who were nonresidents of the United States were considered as births to residents of the exact place of occurrence; in 1964 and 1965 all such births were allocated to "balance of county" of occurrence even if the birth occurred in a city. The change in coding beginning in 1970 to exclude births to nonresidents of the United States from residence data significantly affects the comparability of data with years before 1970 only for Texas. For the total United States the tabulations by place of residence and by place of occurrence are not identical. Births to nonresidents of the United States are included in data by place of occurrence but excluded from data by place of residence, as previously indicated. Residence error--A nationwide test of birth-registration completeness in 1950 provided measures of residence error for natality statistics. According to this test, errors in residence reporting for the country as a whole tend to overstate the number of births to residents of urban areas and to understate the number of births to residents of other areas. This tendency has assumed special importance because of a concomitant development--the increased utilization of hospitals in cities by residents of nearby places--with the result that a number of births are erroneously reported as having occurred to residents of urban areas. Another factor that contributes to this overstatement of urban births is the customary procedure of using "city" addresses for persons living outside the city limits. Incomplete residence--Beginning in 1973 where only the State of residence is reported with no city or county specified and the State named clsnat94.doc - Page 1 is different from the State of occurrence, the birth is allocated to the largest city of the State of residence. Before 1973 such births were allocated to the exact place of occurrence. Geographic classification The rules followed in the classification of geographic areas for live births are contained in the instruction manual mentioned previously. The geographic code structure for 1994 is given in another manual, "Vital Records Geographic Classification, 1982," NCHS Instruction Manual, Part 8. United States--In the statistical tabulations, "United States" refers only to the aggregate of the 50 States and the District of Columbia. Alaska has been included in the U.S. tabulations since 1959 and Hawaii since 1960. Metropolitan statistical areas--The metropolitan statistical areas and primary metropolitan statistical areas (MSA's and PMSA's) used in this report are those established by the U.S. Office of Management and Budget as of April 1, 1990, and used by the U.S. Bureau of the Census (5) except in the New England States. Except in the New England States, an MSA has either a city with a population of at least 50,000, or a Bureau of the Census urbanized area of at least 50,000 and a total MSA population of at least 100,000. A PMSA consists of a large urbanized county, or cluster of counties, that demonstrates very strong internal economic and social links and has a population over 1 million. When PMSA's are defined, the large area of which they are component parts is designated a Consolidated Metropolitan Statistical Area (CMSA) (6). In the New England States the U.S. Office of Management and Budget uses towns and cities rather than counties as geographic components of MSA's and PMSA's. NCHS cannot, however, use this classification for these States because its data are not coded to identify all towns. Instead, the New England County Metropolitan Areas (NECMA's) are used. These areas are established by the U.S. Office of Management and Budget (7) and are made up of county units. Metropolitan and nonmetropolitan counties--Independent cities and counties included in MSA's and PMSA's or NECMA's are included in data for metropolitan counties; all other counties are classified as nonmetropolitan. Population-size groups--Beginning in 1994 vital statistics data for cities and certain other urban places have been classified according to the population enumerated in the 1990 Census of Population. Data are available for individual cities and other urban places of 10,000 or more population. Data for the remaining areas not separately identified are shown in the tables under the heading "Balance of area" or "Balance of county." Classification of areas for 1982-93 was determined by the population enumerated in the 1980 Census of Population. As a result of changes in the enumerated population between 1980 and 1990, some urban places identified in previous reports are no longer included, and a number of other urban places have been added. Urban places other than incorporated cities for which vital statistics data are shown in this report include the following: Each town in New England, New York, and Wisconsin and each township in Michigan, New Jersey, and Pennsylvania that had no incorporated municipality as a subdivision and had either clsnat94.doc - Page 2 25,000 inhabitants or more, or a population of 10,000 to 25,000 and a density of 1,000 persons or more per square mile. Each county in States other than those indicated above that had no incorporated municipality within its boundary and had a density of 1,000 persons or more per square mile. (Arlington County, Virginia, is the only county classified as urban under this rule.) Each place in Hawaii with 10,000 or more population. (There are no incorporated cities in Hawaii.) Race or national origin Beginning with the 1989 data year birth data are tabulated primarily by race of mother. In 1988 and prior years the race or national origin shown in tabulations was that of the newborn child. The race of the child was determined for statistical purposes by an algorithm based on the race of the mother and father as reported on the birth certificate. When the parents were of the same race, the race of the child was the same as the race of the parents. When the parents were of different races and one parent was white, the child was assigned to the race of the other parent. When the parents were of different races and neither parent was white, the child was assigned to the race of the father, with one exception--if either parent was Hawaiian, the child was assigned to Hawaiian. If race was missing for one parent, the child was assigned the race of the parent for whom it was reported. When information on race was missing for both parents, the race of the child was considered not stated and the birth was allocated according to rules discussed on page 4 of the Technical Appendix, volume I, Vital Statistics of the United States, 1988. In 1989 the criteria for reporting the race of the parents did not change and continues to reflect the response of the informant (usually the mother). The most important factor influencing the decision to tabulate births by race of the mother was the decennial revision of the U.S. Standard Certificate of Live Birth in 1989. This revision included many more health questions that are directly associated with the mother, including alcohol and tobacco use, weight gain during pregnancy, medical risk factors, obstetric procedures, complications of labor and/or delivery, and method of delivery. Additionally, many of the other items that have been on the birth certificate for more than two decades also relate directly to the mother, for example, marital status, education level, and receipt of prenatal care. It is more appropriate to use the race of the mother than the race of the child in tabulating these items. A second factor has been the increasing incidence of interracial parentage. In 1994, 4.4 percent of births were to parents of different races, compared with just 1.7 percent in 1974. About half of these births were to white mothers and fathers of another race. There have been two major consequences of the increasing interracial parentage. One is the effect on birth rates by race. The number of white births under the former procedures has been arbitrarily limited to infants whose parents were both white (or one parent if the race of only one parent was reported). At the clsnat94.doc - Page 3 same time, the number of births of other races has been arbitrarily increased to include all births to white mothers and fathers of other races. Thus, prior to 1989, if race of mother had been used, birth rates per 1,000 white women in a given age group would have been higher, while comparable rates for black women and women of other races would have been lower. The other consequence of increasing interracial parentage is the impact on the racial differential in various characteristics of births, particularly in cases where there is generally a large racial disparity, such as the incidence of low birthweight. In this instance, the racial differential is larger when the data are tabulated by race of mother rather than by race of child. The same effect has been noted for characteristics such as nonmarital childbearing, preterm births, late or no prenatal care, and low educational attainment of mother. The third factor influencing the change is the growing proportion of births with race of father not stated, 16 percent in 1994 compared with 9 percent in 1974. This reflects the increase in the proportion of births to unmarried women; in many cases no information is reported on the father. These births were already assigned the race of the mother on a de facto basis. Tabulating births by race of mother provides a more uniform approach, rather than a necessarily arbitrary combination of parental races. This change in the tabulation of births by race presents some problems when analyzing birth data by race, particularly trend data. The problem is likely to be acute for races other than white and black. The categories for race or national origin are "White," "Black," "American Indian,"(including Aleuts and Eskimos), "Chinese," "Japanese, "Hawaiian," "Filipino," and "Other Asian or Pacific Islander" (including Asian Indian). Before 1992 there was also an "other" category, which is now combined with the "Not stated" category. Before 1978 the category "Other Asian or Pacific Islander" was not identified separately but included with "Other" races. The separation of this category allows identification of the category "Asian or Pacific Islander" by combining the new category "Other Asian or Pacific Islander" with Chinese, Japanese, Hawaiian, and Filipino. The category "White" comprises births reported as white and births where race is reported as Hispanic. Before 1964 all births for which race or national origin was not stated were classified as white. Beginning in 1964 changes in the procedures for allocating race when race or national origin is not stated have changed the composition of this category. (See discussion on "Race or national origin not stated.") If the race or national origin of an Asian parent is ill-defined or not clearly identifiable with one of the categories used in the classification (for example, if "Oriental" is entered), an attempt is made to determine the specific race or national origin from the entry for place of birth. If the birthplace is China, Japan, or the Philippines, the race of the parent is assigned to that category. When race cannot be determined from birthplace, it is assigned to the category "Other Asian or Pacific Islander." Race or national origin not stated--If the race of the mother is not defined or not identifiable with one of the categories used in the classification and the race of the father is known, the race of the father is assigned to the mother. Where information for both parents is missing, the race of the mother is allocated electronically according to the specific clsnat94.doc - Page 4 race of the mother on the preceding record with a known race of mother. Data for both parents were missing for only 0.5 percent of birth certificates for 1994. Nearly all statistics by race or national origin for the United States as a whole in 1962 and 1963 are affected by a lack of information for New Jersey, which did not report the race of the parents in those years. Birth rates by race for those years are computed on a population base that excluded New Jersey. For the method of estimating the U.S. population by age, sex, and race excluding New Jersey in 1962 and 1963, see page 4-8 in the Technical Appendix of volume I, Vital Statistics of the United States, 1963. Estimates of births to unmarried mothers by race for the United States, which include special estimates for New Jersey for 1962 and 1963, have been prepared and are shown in table 1-76 of this report. Beginning in 1992, NCHS contracted with seven States with the highest API populations to code births to additional API subgroups. The API subgroups include births to Vietnamese, Asian Indian, Korean, Samoan, Guamanian, and other API women. The seven States included in this reporting area are: California, Hawaii, Illinois, New Jersey, New York, Texas, and Washington. At least two-thirds of the U.S. population of each of these additional API groups lived in the seven-State reporting area (8). Although tables for the expanded API subgroups are not included in this volume, they are available upon request. In addition, the data are available on the detailed natality tapes and CD-ROMs beginning with the 1992 data year. An analytic report based on the 1992 data year is also available upon request (9). Age of mother Beginning in 1989 an item on the birth certificate asks for "Date of Birth." In previous years, "Age (at time of this birth)" was requested. Not all States have revised this item for 1989, and therefore the age of mother either is derived from the reported month and year of birth or coded as stated on the certificate. The age of mother is edited for upper and lower limits. When the age of mother is computed to be under 10 years or 50 years or over, it is considered not stated and is assigned as described below. Age-specific birth rates shown in this report are based on populations of women by age, prepared by the U.S. Bureau of the Census. In census years the decennial census counts are used. In intercensal years, estimates of the population of women by age are published by the U.S. Bureau of the Census in Current Population Reports. The 1990 Census of Population derived age in completed years as of April 1, l990, from the responses to questions on age at last birthday and month and year of birth, with the latter given preference. In the 1960, 1970, and the 1980 Census of Population, age was also derived from month and year of birth. "Age in completed years" was asked in censuses before 1960. This was nearly the equivalent of the former birth certificate question, which the 1950 test of matched birth and census records confirms by showing a high degree of consistency in reporting age in these two sources (10). Median age of mother--Median age is the value that divides an age distribution into two equal parts, one-half of the values being less and one-half being greater. Median ages of mothers for 1960 to the present have been computed from birth rates for 5-year age groups rather than from birth clsnat94.doc - Page 5 frequencies. This method eliminates the effects of changes in the age composition of the childbearing population over time. Changes in the median ages from year to year can thus be attributed solely to changes in the age-specific birth rates. Not stated date of birth of mother--Beginning in 1964 birth records with date of birth of mother and/or age of mother not stated have had age imputed according to the age of mother from the previous birth record of the same race and total-birth order (total of fetal deaths and live births). (See "Vital Statistics Computer Edits for Natality Data," NCHS Instruction Manual, Part 12, page 9.) In 1963 birth records with age not stated were allocated according to the age appearing on the record previously processed for a mother of identical race and parity (number of live births). For 1960-62 not stated ages were distributed in proportion to the known ages for each racial group. Before 1960 this was done for age-specific birth rates but not for the birth frequency tables, which showed a separate category for age not stated. Age of father Age of father is derived from the reported date of birth or coded as stated on the birth certificate. If the age is under 10 years, it is considered not stated and grouped with those cases for which age is not stated on the certificate. Information on age of father is often missing on birth certificates of children born to unmarried mothers, greatly inflating the number of "not stated" in all tabulations by age of father. In computing birth rates by age of father, births tabulated as age of father not stated are distributed in the same proportions as births with known age within each 5-year-age classification of the mother. This procedure is done separately by race. The resulting distributions are summed to form a composite frequency distribution that is the basis for computing birth rates by age of father. This procedure avoids the distortion in rates that would result if the relationship between age of mother and age of father were disregarded. Live-birth order and parity Live-birth order and parity classifications shown in this volume refer to the total number of live births the mother has had including the 1994 birth. Fetal deaths are excluded. Live-birth order indicates what number the present birth represents; for example, a baby born to a mother who has had two previous live births (even if one or both are not now living) has a live-birth order of three. Parity indicates how many live births a mother has had. Before delivery a mother having her first baby has a parity of zero and a mother having her third baby has a parity of two. After delivery the mother of a baby who is a first live birth has a parity of one and the mother of a baby who is a third live birth has a parity of three. Live-birth order and parity are determined from two items on the birth certificate, "Live births now living" and "Live births now dead." Not stated birth order--Before 1969 if both of these items were blank, the birth was considered a first birth. Beginning in 1969, births for which the pregnancy history items were not completed have been tabulated as clsnat94.doc - Page 6 live-birth order not stated. As a result of this revised procedure, 22,686 births in 1969 that would have been assigned to the "First birth order" category under the old rules were assigned to the "Not stated" category. All births tabulated in the "Not stated birth order" category are excluded from the computation of percents. In computing birth rates by live- birth order, births tabulated as birth order not stated are distributed in the same proportion as births of known live-birth order. Date of last live birth The date of last live birth was added to the U.S. Standard Certificate of Live Birth in 1968 for the purpose of providing information on child spacing. The interval since the last live birth is the difference between the date of last live birth and the date of present birth. For an interval to be computed, both the month and year of the last live birth must be valid. This interval is computed only for events to mothers who have had at least one previous live birth. Births for which the interval since last live birth is not stated are excluded from the computation of percents and means. Zero interval--An interval of zero months since the last live birth indicates the second born of a set of twins, the second or third born of a set of triplets, and so forth. Births with an interval of zero months are excluded from the computation of mean intervals. Educational attainment Data on the educational attainment of both parents were collected beginning in 1968 and tabulated for publication in 1969 for the first time. The educational attainment of either parent is defined as "the number of years of school completed." Only those years completed in "regular" schools are counted, that is, a formal educational system of public schools or the equivalent in accredited private or parochial schools. Business or trade schools, such as beauty and barber schools, are not considered "regular" schools for the purposes of this item. No attempt has been made to convert years of school completed in foreign school systems, ungraded school systems, and so forth, to equivalent grades in the American school system. Such entries are included in the category "Not stated." Persons who have completed only a partial year in high school or college are tabulated as having completed the highest preceding grade. For those certificates on which a specific degree is stated, years of school completed is coded to the level at which the degree is most commonly attained; for example, persons reporting B.A., A.B., or B.S. degrees are considered to have completed 16 years of school. Education not stated--The category "Not stated" includes all records in reporting areas for which there is no information on years of school completed as well as all records for which the information provided is not compatible with coding specifications. Births tabulated as education not stated are excluded from the computations of percents. clsnat94.doc - Page 7 Marital status Beginning with 1980 data, national estimates of births to unmarried women are derived from two sources. In 1994 marital status was reported directly on the birth certificates of 45 States and the District of Columbia. In the remaining five States, which lack such an item (California, Connecticut, Michigan, Nevada, and New York), marital status is inferred from a comparison of the child's and parents' surnames. This procedure represents a substantial departure from the method used before 1980 to prepare national estimates of births to unmarried women, which assumed that the incidence of births to unmarried women in States with no direct question on marital status was the same as the incidence in reporting States in the same geographic division. The current method uses related information on the birth certificate to improve the quality of national data on this topic, as well as to provide data for the individual nonreporting States. Beginning in 1980 a birth in a nonreporting State is classified as occurring to a married woman if the parents' surnames are the same, or if the child's and father's surnames are the same and the mother's current surname cannot be obtained from the informant item of the birth certificate. A birth is classified as occurring to an unmarried woman if the father's name is missing, if the parents' surnames are different, or if the father's and child's surnames are different and the mother's current surname is missing. Because of the continued substantial increases in nonmarital childbearing throughout the 1980's, the data have been intensively evaluated in each year, 1985-94. There has been continuing concern that the current method might overstate the number of births to unmarried women because it incorporates data based on a comparison of surnames. This is because births to women who have retained their maiden surname as their legal surname after marriage and who are frequently older, well-educated women, would be classified as nonmarital births. Trends based on data incorporating inferential statistics can be compared with trends based on the geographic estimates for the 1980-94 period to show the impact of the two methods. The trends for the two methods are similar for all races combined and for white and black births. Between 1980 and 1994, birth rates for unmarried white women increased 112 percent based on data incorporating inferential information and 116 percent based on the geographic estimates. Birth rates for unmarried black women increased 1 percent based on the inferential data and declined 2 percent based on geographic estimates. Michigan and Texas births--the number of births to unmarried women in Michigan was underreported during the years 1988-93, but the greatest undercount, numerically, was for 1990-93. Michigan had separate counts of the numbers of births with paternity acknowledgements, but did not include them with the counts of unmarried women based on the general inferential procedures that were provided to NCHS. The underreporting began in 1988, and was about 25 percent for the years 1988-93. In 1993 NCHS reported 36,326 births to unmarried women in Michigan, 26 percent below the number that included paternity affidavits (49,281) (11). Thus, there is a considerable discontinuity in the nonmarital birth data for Michigan from 1993 to 1994. The proportion of nonmarital births reported to NCHS increased from 26 percent to 35 percent. The number of births to unmarried women in Texas was underreported during the years 1989-93. As a result of legislation passed in 1989, a birth was clsnat94.doc - Page 8 considered to have occurred to a married woman if the mother provides any information about the father, or if a paternity affidavit has been filed. The measurement of marital status for Texas births improved beginning with the 1994 data year because a direct question on marital status was added to the Texas birth certificate. However, there is a considerable discontinuity in the data for Texas from 1993 to 1994. The proportion of births to unmarried mothers increased from 17 to 29 percent. No adjustments are made during the data processing for errors in the reporting of marital status on the birth records of the 45 reporting States and the District of Columbia because the extent of this reporting problem is unknown. When marital status is not stated on the birth certificate of a reporting area, the mother is considered married. When births to unmarried women are reported as second-or higher-order births, it is not known whether the mother was married or unmarried when the previous deliveries occurred, because her marital status at the time of these earlier births is not available from the birth record. Rates for 1940 and 1950 are based on decennial census counts. Rates for 1955-94 are based on a smoothed series of population estimates (12). Because of sampling error, the original U.S. Bureau of the Census population estimates by marital status fluctuate erratically from year to year; therefore, they have been smoothed so that the rates do not show similar variations. These rates differ from those published in volumes of Vital Statistics of the United States before 1969, which were based on the original estimates provided annually by the U.S. Bureau of the Census. Birth rates by marital status for 1971-79 have been revised and differ from rates published before 1980 in volumes of Vital Statistics of the United States (see "Computation of rates and other measures"). Place of delivery and attendant at birth The 1989 revision of the U.S. Standard Certificate of Live Birth included separate categories for freestanding birthing centers, the mother's residence, and clinic or doctor's office as the place of birth. Prior to 1989, place of birth was classified simply as either "In hospital" or "Not in hospital." Births occurring in hospitals, institutions, clinics, centers, or homes were included in the category "In hospital." In this context the word "homes" does not refer to the mother's residence but to an institution, such as a home for unmarried women. Birthing centers were included in either category, depending on each State's assessment of the facility. Beginning in 1989 births occurring in clinics and in birthing centers not attached to a hospital are classified as "Not in hospital." This change in classification may account in part for the lower proportion of "In hospital" births compared with previous years. (The change in classification of clinics should have minor impact because comparatively few births occur in these facilities, but the effect of any change in classification of freestanding birthing centers is unknown.) Beginning in 1975 the attendant at birth and place of delivery items were coded independently, primarily to permit the identification of the person in attendance at hospital deliveries. The 1989 certificate includes separate classifications for "M.D." (Doctor of Medicine), "D.O." (Doctor of Osteopathy), "C.N.M." (certified nurse midwife), "Other midwife," and "Other" attendants. In earlier certificates births attended by certified nurse midwives were grouped with those attended by lay midwives. The new clsnat94.doc - Page 9 certificate also facilitates the identification of home births, births in freestanding birthing centers, and births in clinics or physician offices. Data shown in this volume for the "In hospital" category for 1975-88 include all births in clinics or maternity centers, regardless of the attendant. Data for 1975-77 published before 1980 included clinic and center births in the category "In hospital" only when the attendant was a physician. Data shown for 1975-77 in tables 1-87 and 1-88, therefore, differ from data published before 1980. As a result of this change, for 1975 an additional 12,352 births are now classified as occurring in hospitals, raising the percent of births occurring in hospitals from 98.7 to 99.1. Similarly, for 1976 the number of births occurring in hospitals increased by 14,133 and the percent in hospitals raised from 98.6 to 99.1; for 1977 the increase is 15,937 and the percent in hospitals raised from 98.5 to 99.0. For 1974 and earlier the "In hospital" category includes all births in hospitals or institutions and births in clinics, centers, or maternity homes only when attended by physicians. The "Not in hospital" category includes births for which no information is reported on place of birth. Before 1975 births for which the stated place of birth was a "doctor's office" and delivery was by a physician were included in the category "In hospital." Beginning in 1975 these births were tabulated as "Not in hospital" and included with births delivered by physicians in this category. Although the actual number of such births is unknown, the effect of the change is minimal. In 1974, 0.3 percent of all births were delivered by physicians outside of hospitals; in 1975 this proportion was 0.4 percent. Babies born on the way to or on arrival at the hospital are classified as having been born in the hospital. This may account for some of the hospital births not delivered by physicians or midwives. Beginning in 1993, all in-hospital births occurring in Illinois where the attendant was classified as an "other" midwife were changed to certified nurse-midwife. This was necessary because almost all of these births were delivered by midwives certified by the American College of Nurse Midwives but because Illinois does not certify midwives, many of these births were classified as "other" midwives. Birthweight Birthweight is reported in some areas in pounds and ounces rather than in grams. However, the metric system has been used in tabulating and presenting the statistics to facilitate comparison with data published by other groups. The categories for birthweight were changed in 1979 to be consistent with the recommendations in the Ninth Revision of the International Classification of Diseases (ICD-9). The categories in gram intervals and their equivalents in pounds and ounces are as follows: Less than 500 grams =3D 1 lb 1 oz or less 500-999 grams =3D 1 lb 2 oz-2 lb 3 oz 1,000-1,499 grams =3D 2 lb 4 oz-3 lb 4 oz 1,500-1,999 grams =3D 3 lb 5 oz-4 lb 6 oz 2,000-2,499 grams =3D 4 lb 7 oz-5 lb 8 oz 2,500-2,999 grams =3D 5 lb 9 oz-6 lb 9 oz 3,000-3,499 grams =3D 6 lb 10 oz-7 lb 11 oz clsnat94.doc - Page 10 3,500-3,999 grams =3D 7 lb 12 oz-8 lb 13 oz 4,000-4,499 grams =3D 8 lb 14 oz-9 lb 14 oz 4,500-4,999 grams =3D 9 lb 15 oz-11 lb 0 oz 5,000 grams or more =3D 11 lb l oz or more The ICD-9 defines low birthweight as less than 2,500 grams. This is a shift of 1 gram from the previous criterion of 2,500 grams or less, which was recommended by the American Academy of Pediatrics in 1935 and adopted in 1948 by the World Health Organization in the Sixth Revision of the International Lists of Diseases and Causes of Death. After data classified by pounds and ounces are converted to grams, median weights are computed and rounded before publication. To establish the continuity of class intervals needed to convert pounds and ounces to grams, the end points of these intervals are assumed to be half an ounce less at the lower end and half an ounce more at the upper end. For example, 2 lb 4 oz-3 lb 4 oz is interpreted as 2 lb 3 1/2 oz-3 lb 4 1/2 oz. Births for which birthweight is not reported are excluded from the computation of percents and medians. Period of gestation The period of gestation is defined as beginning with the first day of the last normal menstrual period (LMP) and ending with the day of the birth. The LMP is used as the initial date because it can be more accurately determined than the date of conception, which usually occurs 2 weeks after the LMP. Births occurring before 37 completed weeks of gestation are considered to be "preterm" or "premature" for purposes of classification. At 37-41 weeks gestation, births are considered to be "term," and at 42 completed weeks and over, "postterm." These distinctions are according to the ICD-9 definitions. The 1989 revision of the U.S. Standard Certificate of Live Birth included a new item, "clinical estimate of gestation," that is being compared with length of gestation computed from the LMP date when the latter appears to be inconsistent with birthweight. This is done for normal-weight births of apparently short gestations and very low-birthweight births reported to be full term. The clinical estimate also was used if the date of the LMP was not reported. The period of gestation for 4.1 percent of the births in 1994 was based on the clinical estimate of gestation. For 96 percent of these records the clinical estimate was used because the LMP date was not reported. For the remaining 4 percent the clinical estimate was used because it was compatible with the reported birthweight, whereas the LMP-computed gestation was not. In cases where the reported birthweight was inconsistent with both the LMP-computed gestation and the clinical estimate of gestation, the LMP-computed gestation was used if it was within 5 weeks of the clinical estimate and birthweight was reclassified as "not stated." If the reported birthweight was inconsistent with both the LMP-computed gestation and the clinical estimate of gestation, gestation and birthweight were classified as "not stated" if the LMP-computed gestation was not within 5 weeks of the clinical estimate. These changes result in only a very small discontinuity in the data. For further information on the use of the clinical estimate of gestation see "Computer Edits for Natality Data, Effective 1989," NCHS Instruction Manual, Part 12, pages 34-36. clsnat94.doc - Page 11 Before 1981 the period of gestation was computed only when there was a valid month, day, and year of LMP. However, length of gestation could not be determined from a substantial number of live-birth certificates each year because the day of LMP was missing. Beginning in 1981 weeks of gestation have been imputed for records with missing day of LMP when there is a valid month and year. Each such record is assigned the gestational period in weeks of the preceding record that has a complete LMP date with the same computed months of gestation and the same 500-gram birthweight interval. The effect of the imputation procedure is to increase slightly the proportion of preterm births and to lower the proportion of births at 39, 40, 41, and 42 weeks of gestation. A more complete discussion of this procedure and its implications is presented in a previous report (13). Because of postconception bleeding or menstrual irregularities, the presumed date of LMP may be in error. In these instances the computed gestational period may be longer or shorter than the true gestational period, but the extent of such errors is unknown. Month of pregnancy prenatal care began For those records in which the name of the month is entered for this item, instead of first, second, third, and so forth, the month of pregnancy in which prenatal care began is determined from the month named and the month last normal menses began. For these births, if the item "Date last normal menses began" is not stated, the month of pregnancy in which prenatal care began is tabulated as not stated. Number of prenatal visits Tabulations of the number of prenatal visits were presented for the first time in 1972. Beginning in 1989 these data were collected from the birth certificates of all States. Percent distributions and the median number of prenatal visits exclude births to mothers who had no prenatal care. Apgar score One- and 5-minute Apgar scores were added to the U.S. Standard Certificate of Live Birth in 1978 to evaluate the condition of the newborn infant at 1 and 5 minutes after birth. The Apgar score is a useful measure of the need for resuscitation and a predictor of the infant's chances of surviving the first year of life. It is a summary measure of the infant's condition based on heart rate, respiratory effort, muscle tone, reflex irritability, and color. Each of these factors is given a score of 0, 1, or 2; the sum of these 5 values is the Apgar score, which ranges from 0 to 10. A score of 10 is optimum, and a low score raises some doubts about the survival and subsequent health of the infant. In 1994 the reporting area for the 1- and 5-minute Apgar scores was comprised of 48 States and the District of Columbia, accounting for 78 percent of all births in the United States. California and Texas did not have information on Apgar scores on their birth certificate. clsnat94.doc - Page 12 Tobacco and alcohol use during pregnancy The checkbox format allows for classification of a mother as a smoker or drinker during pregnancy and for reporting the average number of cigarettes smoked per day or drinks consumed per week. When smoking and/or drinking status is not reported or is inconsistent with the quantity of cigarettes or drinks reported, the status is changed to be consistent with the amount reported. For example, if the drinking status is reported as "no" but one or more average drinks a week are reported, the mother is classified as a drinker. If the number of cigarettes smoked per day is reported as one or more, the mother is considered a smoker. When one (or a fraction of one) drink a week is recorded, the mother is classified as a drinker. For records on which the number of drinks or number of cigarettes is reported as a span, for example, 10-15, the lower number is used. The number of drinkers and number of drinks reported on birth certificates are believed to underestimate actual alcohol use. Data on tobacco use were collected by 46 States and the District of Columbia, and New York in 1994. This reporting area accounted for 79 percent of all births in the U.S. in 1994. Information on alcohol use was included on the certificates of 48 States and the District of Columbia, accounting for 85 percent of all U.S. births in 1994. California and South Dakota did not include items on alcohol use on their birth certificates. Weight gained during pregnancy Weight gain is reported in pounds. A loss of weight is reported as zero gain. Computations of median weight gain were based on ungrouped data. This item was included on the certificates of 49 States and the District of Columbia; California did not report this information. This reporting area excluding California accounted for 86 percent of all births in the United States in 1994. Medical risk factors for this pregnancy In 1994 an item on medical risk factors was included on the birth certificates of all States and the District of Columbia, but two States did not report all of the 16 risk factors. Texas did not report genital herpes or uterine bleeding while Kansas did not report Rh sensitization. The format allows for the designation of more than one risk factor and includes a choice of "None." Accordingly, if the item is not completed, it is classified as "Not stated." The following definitions are adapted and abbreviated from a set of definitions compiled by a committee of Federal and State health statistics officials for the Association for Vital Records and Health Statistics (14). Definitions of medical terms Anemia--Hemoglobin level of less than 10.0 g/dL during pregnancy or a hematocrit of less than 30 percent during pregnancy. Cardiac disease--Disease of the heart. Acute or chronic lung disease--Disease of the lungs during pregnancy. Diabetes--Metabolic disorder characterized by excessive discharge of urine and persistent thirst; includes juvenile onset, adult onset, and gestational diabetes during pregnancy. clsnat94.doc - Page 13 Genital herpes--Infection of the skin of the genital area by herpes simplex virus. Hydramnios/Oligohydramnios--Any noticeable excess (hydramnios) or lack (oligohydramnios) of amniotic fluid. Hemoglobinopathy--A blood disorder caused by alteration in the genetically determined molecular structure of hemoglobin (for example, sickle cell anemia). Hypertension, chronic--Blood pressure persistently greater than 140/90, diagnosed prior to onset of pregnancy or before the 20th week of gestation. Hypertension, pregnancy-associated--An increase in blood pressure of at least 30 mm Hg systolic or 15 mm Hg diastolic on two measurements taken 6 hours apart after the 20th week of gestation. Eclampsia--The occurrence of convulsions and/or coma unrelated to other cerebral conditions in women with signs and symptoms of pre-eclampsia. Incompetent cervix--Characterized by painless dilation of the cervix in the second trimester or early in the third trimester of pregnancy, with prolapse of membranes through the cervix and ballooning of the membranes into the vagina, followed by rupture of membranes and subsequent expulsion of the fetus. Previous infant 4,000+ grams--The birthweight of a previous live-born child was over 4,000 grams (8 lbs 13 oz). Previous preterm or small-for-gestational-age infant--Previous birth of an infant prior to term (before 37 completed weeks of gestation) or of an infant weighing less than the 10th percentile for gestational age using a standard weight-for-age chart. Renal disease--Kidney disease. Rh sensitization--the process or state of becoming sensitized to the Rh factor as when an Rh-negative woman is pregnant with an Rh-positive fetus. Uterine bleeding--Any clinically significant bleeding during the pregnancy, taking into consideration the stage of pregnancy; any second or third trimester bleeding of the uterus prior to the onset of labor. Obstetric procedures This item includes six specific obstetric procedures. Birth records with "Obstetric procedures" left blank are considered "not stated." Data on obstetric procedures were reported by all States and the District of Columbia. The following definitions are adapted and abbreviated from a set of definitions compiled by a committee of Federal and State health statistics officials for the Association for Vital Records and Health Statistics (14). Definitions of medical terms Amniocentesis--Surgical transabdominal perforation of the uterus to obtain amniotic fluid to be used in the detection of genetic disorders, fetal abnormalities, and fetal lung maturity. Electronic fetal monitoring--Monitoring with external devices applied to the maternal abdomen or with internal devices with an electrode attached to the fetal scalp and a catheter through the cervix into the uterus, to detect and record fetal heart tones and uterine contractions. clsnat94.doc - Page 14 Induction of labor--The initiation of uterine contractions before the spontaneous onset of labor by medical and/or surgical means for the purpose of delivery. Stimulation of labor--Augmentation of previously established labor by use of oxytocin. Tocolysis--Use of medications to inhibit preterm uterine contractions to extend the length of pregnancy and therefore avoid a preterm birth. Ultrasound--Visualization of the fetus and placenta by means of sound waves. Complications of labor and/or delivery The checkbox format allows for the selection of 15 specific complications and for the designation of more than 1 complication where appropriate. A choice of "None" is also included. Accordingly, if the item is not completed, it is classified as "not stated." All States and the District of Columbia included this item on their birth certificates. However, not all of the complications were reported by all reporting States (see table A). Definitions of medical terms Febrile--A fever greater than 100 degrees F. or 38 C. occurring during labor and/or delivery. Meconium, moderate/heavy--Meconium consists of undigested debris from swallowed amniotic fluid, various products of secretion, excretion and shedding by the gastrointestinal tract; moderate to heavy amounts of meconium in the amniotic fluid noted during labor and/or delivery. Premature rupture of membranes (more than 12 hours)--Rupture of the membranes at any time during pregnancy and more than 12 hours before the onset of labor. Abruptio placenta--Premature separation of a normally implanted placenta from the uterus. Placenta previa--Implantation of the placenta over or near the internal opening of the cervix. Other excessive bleeding--The loss of a significant amount of blood from conditions other than abruptio placenta or placenta previa. Seizures during labor--Maternal seizures occurring during labor from any cause. Precipitous labor (less than 3 hours)--Extremely rapid labor and delivery lasting less than 3 hours. Prolonged labor (more than 20 hours)--Abnormally slow progress of labor lasting more than 20 hours. Dysfunctional labor--Failure to progress in a normal pattern of labor. Breech/Malpresentation--At birth, the presentation of the fetal buttocks rather than the head, or other malpresentation. Cephalopelvic disproportion--The relationship of the size, presentation and position of the fetal head to the maternal pelvis prevents dilation of the cervix and/or descent of the fetal head. Cord prolapse--Premature expulsion of the umbilical cord in labor before the fetus is delivered. clsnat94.doc - Page 15 The updated information for 1995 is provided in Table A. Table A. Percent of Birth Records on Which Specified Items Were Not Stated: United States and Each State, Puerto Rico, Virgin Islands, and Guam: 1995 [By place of residence] Number Place Attendant Mother's of of at birth- Father's Father's Area births birth birth place age race Total of reporting areas 1/ 3,899,589 0.0 0.2 0.2 15.2 15.2 Alabama 60,329 - 0.0 0.1 27.1 27.1 Alaska 10,244 0.0 .0 .2 11.7 14.5 Arizona 72,463 .0 .1 .3 28.1 30.2 Arkansas 35,175 .0 .1 .4 19.5 19.6 California 552,045 .0 .9 .0 6.3 3.8 Colorado 54,332 .0 .0 .2 11.8 12.8 Connecticut 44,334 .0 .0 .4 9.9 11.5 Delaware 10,266 .0 .0 .4 25.7 32.4 Dist. of Columbia 9,014 .0 - 1.2 50.7 55.5 Florida 188,723 .0 - .2 19.5 19.5 Georgia 112,282 .0 .0 .3 19.5 20.0 Hawaii 18,595 - .0 .1 10.6 10.7 Idaho 18,035 .0 .0 .2 8.0 10.5 Illinois 185,812 .1 .0 .1 17.4 17.9 Indiana 82,835 .0 .1 .2 13.5 13.2 Iowa 36,810 .0 .0 .2 13.1 14.5 Kansas 37,201 - .1 .0 11.0 11.3 Kentucky 52,377 .0 .0 - 19.8 19.8 Louisiana 65,641 .0 .0 .0 26.4 26.5 Maine 13,896 - .0 .0 16.2 17.2 Maryland 72,396 .0 .0 .9 8.1 9.0 Massachusetts 81,648 .0 .0 .5 10.6 9.5 Michigan 134,642 .0 .3 .1 19.1 21.3 Minnesota 63,263 .1 .0 .3 9.6 12.5 Mississippi 41,344 .0 .0 .2 27.6 27.3 Missouri 73,028 .0 .0 .2 18.8 22.1 Montana 11,142 - .4 .0 9.6 11.2 Nebraska 23,243 - .0 .0 12.4 12.9 Nevada 25,056 - .0 .7 23.0 23.4 New Hampshire 14,665 .0 .0 .1 8.7 9.5 New Jersey 114,828 .1 .1 .4 9.9 11.1 New Mexico 26,920 .0 .0 1.0 26.9 26.4 clsnat94.doc - Page 16 Table A. Percent of Birth Records on Which Specified Items Were Not Stated: United States and Each State, Puerto Rico, Virgin Islands, and Guam: 1995 [By place of residence] Number Place Attendant Mother's of of at birth- Father's Father's Area births birth birth place age race Total of reporting areas 1/ 3,899,589 0.0 0.2 0.2 15.2 15.2 New York 271,369 .1 .1 .4 18.8 18.9 North Carolina 101,592 - .0 .0 18.4 18.4 North Dakota 8,476 - - .0 9.4 10.7 Ohio 154,064 .0 .0 .3 13.5 13.9 Oklahoma 45,672 - .0 .1 17.4 19.6 Oregon 42,811 - .7 .1 14.5 5.6 Pennsylvania 151,850 .0 .0 .7 6.7 2.9 Rhode Island 12,776 - - .2 14.8 15.3 South Carolina 50,926 .0 .0 .2 30.9 31.0 South Dakota 10,475 - .1 2.7 10.4 11.1 Tennessee 73,173 - .0 .1 16.6 16.6 Texas 322,753 .0 .0 .4 16.6 16.5 Utah 39,577 .0 .0 .1 8.6 9.0 Vermont 6,783 - - .0 4.5 5.2 Virginia 92,578 .0 .0 .1 20.0 20.3 Washington 77,228 .0 .0 .5 13.4 12.2 West Virgin 21,162 - - .1 14.0 17.2 Wisconsin 67,479 .0 - .0 17.5 27.0 Wyoming 6,261 - .0 .1 13.1 13.7 Puerto Rico 63,419 .0 .0 - 2.6 ... Virgin Islands 2,032 - .3 - 26.4 27.0 Guam 4,179 - .3 .4 27.6 27.8 clsnat94.doc - Page 17 Table A. Percent of Birth Records on Which Specified Items Were Not Stated: United States and Each State, Puerto Rico, Virgin Islands, and Guam: 1995 [By place of residence] Number Educational Live- of Hispanic Origin attainment birth Area births Mother Father Mother order Total of reporting areas 1/ 3,899,589 1.5 16.0 1.5 0.7 Alabama 60,329 - 27.1 0.5 0.0 Alaska 10,244 .4 12.9 2.1 .2 Arizona 72,463 .3 30.4 2.6 .2 Arkansas 35,175 .2 19.6 .8 .1 California 552,045 .4 3.5 .9 .1 Colorado 54,332 .4 13.8 1.4 .3 Connecticut 44,334 4.0 13.2 5.8 11.0 Delaware 10,266 .1 31.8 .3 .2 Dist. of Columbia 9,014 .7 50.6 6.0 .6 Florida 188,723 .0 20.5 .3 .0 Georgia 112,282 .5 19.9 1.0 .2 Hawaii 18,595 .1 9.8 .3 .0 Idaho 18,035 .6 10.1 3.0 .9 Illinois 185,812 .0 17.5 .6 .1 Indiana 82,835 .2 13.2 1.3 .2 Iowa 36,810 .7 14.9 1.6 .2 Kansas 37,201 1.0 12.5 .2 .0 Kentucky 52,377 .1 28.3 .2 .4 Louisiana 65,641 .0 26.4 .1 .1 Maine 13,896 1.6 18.5 .5 .1 Maryland 72,396 1.1 6.4 3.2 4.7 Massachusetts 81,648 .7 9.6 .6 .4 Michigan 134,642 4.9 25.0 .9 .5 Minnesota 63,263 8.7 19.2 2.6 .4 Mississippi 41,344 .1 27.4 .2 .0 Missouri 73,028 .1 21.8 1.0 .9 Montana 11,142 3.5 14.4 .2 .1 Nebraska 23,243 1.8 14.1 .1 .0 Nevada 25,056 .3 22.5 1.9 .4 New Hampshire 14,665 3.6 12.2 .7 .1 New Jersey 114,828 .7 10.6 3.8 1.9 New Mexico 26,920 .0 26.4 3.4 .6 New York 271,369 11.4 27.6 3.2 1.1 North Carolina 101,592 .0 18.4 .2 .0 North Dakota 8,476 1.4 11.9 .2 .0 clsnat94.doc - Page 18 Table A. Percent of Birth Records on Which Specified Items Were Not Stated: United States and Each State, Puerto Rico, Virgin Islands, and Guam: 1995 [By place of residence] Number Educational Live- of Hispanic Origin attainment birth Area births Mother Father Mother order Total of reporting areas 1/ 3,899,589 1.5 16.0 1.5 0.7 Ohio 154,064 .2 12.0 .4 .0 Oklahoma 45,672 .1 19.5 3.2 .5 Oregon 42,811 .1 5.8 .8 .0 Pennsylvania 151,850 .2 2.3 2.0 .1 Rhode Island 12,776 13.9 24.7 2.6 2.0 South Carolina 50,926 .1 30.7 3.5 .1 South Dakota 10,475 .1 12.8 .3 .0 Tennessee 73,173 .0 16.6 .2 .0 Texas 322,753 .2 16.4 1.1 1.9 Utah 39,577 .2 5.7 1.6 .6 Vermont 6,783 5.6 9.5 2.2 .2 Virginia 92,578 .1 20.0 .5 .3 Washington 77,228 3.4 13.8 10.3 3.9 West Virgin 21,162 .0 17.1 .6 .1 Wisconsin 67,479 .0 27.0 .1 .0 Wyoming 6,261 .1 13.4 .3 .1 Puerto Rico 63,419 ... ... .4 .0 Virgin Islands 2,032 1.3 26.7 2.1 .8 Guam 4,179 .4 27.3 1.2 .9 clsnat94.doc - Page 19 Table A. Percent of Birth Records on Which Specified Items Were Not Stated: United States and Each State, Puerto Rico, Virgin Islands, and Guam: 1995 [By place of residence] Month Number Number Length prenatal of pre- Area of of care natal births Gestation began visit Total of reporting areas 1/ 3,899,589 0.9 2.4 3.4 Alabama 60,329 0.1 0.7 1.1 Alaska 10,244 .3 1.1 1.1 Arizona 72,463 .2 1.9 5.6 Arkansas 35,175 .4 2.2 3.2 California 552,045 2/ 4.3 .3 2.3 Colorado 54,332 .0 1.5 2.3 Connecticut 44,334 3.5 7.0 9.2 Delaware 10,266 .1 .7 1.1 Dist. of Columbia 9,014 .4 10.5 10.9 Florida 188,723 .1 .8 2.1 Georgia 112,282 .1 1.5 1.1 Hawaii 18,595 2.3 3.0 3.5 Idaho 18,035 1.0 2.7 4.6 Illinois 185,812 .2 1.7 2.0 Indiana 82,835 .1 1.7 2.7 Iowa 36,810 .2 1.4 4.2 Kansas 37,201 .1 .5 .8 Kentucky 52,377 .1 .9 1.0 Louisiana 65,641 .1 .4 .7 Maine 13,896 .2 .6 .6 Maryland 72,396 .8 7.9 14.4 Massachusetts 81,648 .2 .4 .7 Michigan 134,642 .1 2.8 5.0 Minnesota 63,263 .9 3.9 3.4 Mississippi 41,344 .2 .7 .7 Missouri 73,028 .2 1.9 2.5 Montana 11,142 .1 .3 .6 Nebraska 23,243 .0 .2 .4 Nevada 25,056 .5 2.0 6.5 New Hampshire 14,665 .3 2.0 2.7 New Jersey 114,828 .9 5.6 8.0 New Mexico 26,920 .3 3.7 4.6 New York 271,369 .3 8.2 5.5 clsnat94.doc - Page 20 Table A. Percent of Birth Records on Which Specified Items Were Not Stated: United States and Each State, Puerto Rico, Virgin Islands, and Guam: 1995 [By place of residence] Month Number Number Length prenatal of pre- Area of of care natal births Gestation began visit Total of reporting areas 1/ 3,899,589 0.9 2.4 3.4 North Carolina 101,592 .1 .5 .6 North Dakota 8,476 .1 .5 .5 Ohio 154,064 .1 1.1 1.3 Oklahoma 45,672 2.7 8.1 9.2 Oregon 42,811 .0 .3 .5 Pennsylvania 151,850 .2 1.9 2.2 Rhode Island 12,776 .5 7.7 8.4 South Carolina 50,926 .1 .8 1.1 South Dakota 10,475 .1 .6 .6 Tennessee 73,173 .2 1.3 1.5 Texas 322,753 .6 2.8 5.5 Utah 39,577 .1 .6 .6 Vermont 6,783 .1 2.7 1.1 Virginia 92,578 .1 .7 1.1 Washington 77,228 1.3 7.5 11.3 West Virgin 21,162 .2 3.3 2.6 Wisconsin 67,479 .0 .2 .3 Wyoming 6,261 .0 .4 .3 Puerto Rico 63,419 .1 .5 .2 Virgin Islands 2,032 1.4 .6 3.2 Guam 4,179 .6 3.3 3.7 clsnat94.doc - Page 21 Table A. Percent of Birth Records on Which Specified Items Were Not Stated: United States and Each State, Puerto Rico, Virgin Islands, and Guam: 1995 [By place of residence] Number 5-minute Medical Area of Birth Apgar risk Tobacco Alcohol births weight score factors use use Total of reporting areas 1/ 3,899,589 0.1 0.7 1.2 1.5 1.6 Alabama 60,329 0.1 0.3 0.3 0.4 0.5 Alaska 10,244 .3 .7 .2 .5 .6 Arizona 72,463 .2 .5 .0 .5 .5 Arkansas 35,175 .2 3.9 .6 .7 .8 California 552,045 .0 ... .0 ... ... Colorado 54,332 .0 .4 .0 .8 .7 Connecticut 44,334 .0 4.2 13.5 11.6 11.6 Delaware 10,266 .0 .3 .0 .2 .2 Dist. of Columbia 9,014 .2 .6 .0 .5 .5 Florida 188,723 .0 .3 .0 .1 .1 Georgia 112,282 .0 .4 .5 .3 .3 Hawaii 18,595 .5 1.8 1.1 .2 .2 Idaho 18,035 .1 .6 5.3 .6 .9 Illinois 185,812 .0 .3 .1 1.0 .2 Indiana 82,835 .3 .6 .3 ... .5 Iowa 36,810 .0 .6 .2 1.8 2.1 Kansas 37,201 .0 .3 3/1.5 1.6 1.6 Kentucky 52,377 .1 .4 4.7 3.7 3.5 Louisiana 65,641 .0 .3 .1 .3 1.0 Maine 13,896 .2 .5 .5 2.8 3.7 Maryland 72,396 .1 .5 .0 2.9 3.1 Massachusetts 81,648 .2 .3 .6 .3 3.0 Michigan 134,642 .3 .7 .2 1.5 1.2 Minnesota 63,263 .1 .8 4.8 4.3 4.5 Mississippi 41,344 .1 .6 .2 .4 .4 Missouri 73,028 .0 .6 .1 .7 .7 Montana 11,142 .1 .4 .1 .5 .5 Nebraska 23,243 .0 .1 .0 1.0 1.0 Nevada 25,056 .0 2.9 .9 1.3 1.5 New Hampshire 14,665 .3 .4 .1 .1 .4 New Jersey 114,828 .4 .5 .9 1.4 1.3 New Mexico 26,920 .2 3.1 .1 .7 .7 New York 271,369 .1 1.2 3.6 4/5.7 3.1 North Carolina 101,592 .1 .4 .0 .1 .1 North Dakota 8,476 .1 .3 .5 .9 1.0 clsnat94.doc - Page 22 Table A. Percent of Birth Records on Which Specified Items Were Not Stated: United States and Each State, Puerto Rico, Virgin Islands, and Guam: 1995 [By place of residence] Number 5-minute Medical Area of Birth Apgar risk Tobacco Alcohol births weight score factors use use Total of reporting areas 1/ 3,899,589 0.1 0.7 1.2 1.5 1.6 Ohio 154,064 .1 .4 .1 .6 .4 Oklahoma 45,672 .6 4.2 25.2 20.0 20.4 Oregon 42,811 .0 .5 .7 .5 .6 Pennsylvania 151,850 .1 .4 .1 .5 .2 Rhode Island 12,776 .2 .6 4.9 1.8 2.0 South Carolina 50,926 .0 .4 .0 .2 .2 South Dakota 10,475 .1 .4 .2 ... ... Tennessee 73,173 .1 .4 .1 .3 .3 Texas 322,753 .1 ... 5/1.6 .3 .4 Utah 39,577 .1 .9 .2 .2 .2 Vermont 6,783 .1 .4 .1 .7 1.7 Virginia 92,578 .1 .3 .1 .2 .3 Washington 77,228 .2 .4 .1 2.8 9.5 West Virginia 21,162 .0 .2 .4 .9 3.2 Wisconsin 67,479 .0 .5 .1 .1 .1 Wyoming 6,261 - .5 .0 1.1 1.2 Puerto Rico 63,419 .0 .3 .1 .0 .0 Virgin Islands 2,032 .4 3.5 28.9 2.0 2.3 Guam 4,179 .3 1.7 2.1 2.7 3.0 1/ Excludes data for Puerto Rico, Virgin Islands, and Guam. 2/ California reports date last normal menses began but does not report clinical estimate of gestation. 3/ Kansas does not report Rh sensitization. 4/ New York city (but not New York State) reports tobacco use. 5/ Texas does not report genital herpes and uterine bleeding. 6/ Massachusetts, Nebraska, and Texas do not report birth injury. 7/ New York city does not report assisted ventilation less than 30 minutes and assisted ventilation of 30 minutes or more. 8/ New York State (but not New York city) reports congenital anomalies. 9/ Texas does not report anesthetic complications and fetal distress. 10/ Wisconsin does not report fetal alcohol syndrome. clsnat94.doc - Page 23 Table A. Percent of Birth Records on Which Specified Items Were Not Stated: United States and Each State, Puerto Rico, Virgin Islands, and Guam: 1995 (Page 2 of 2) [By place of residence] Complica- Number tions of Area of Weight Obstetric labor and/ births gain procedures or delivery Total of reporting areas 1/ 3,899,589 9.0 0.8 1.0 Alabama 60,329 5.9 0.3 0.3 Alaska 10,244 2.2 .1 .1 Arizona 72,463 13.4 .0 .0 Arkansas 35,175 7.3 .4 .6 California 552,045 ... .0 .1 Colorado 54,332 6.7 .0 .0 Connecticut 44,334 27.6 12.5 13.8 Delaware 10,266 1.2 .0 .0 Dist. of Columbia 9,014 11.4 .0 - Florida 188,723 4.3 .0 .0 Georgia 112,282 4.9 .1 .0 Hawaii 18,595 12.4 .1 1.1 Idaho 18,035 13.1 5.1 5.3 Illinois 185,812 4.9 .1 .0 Indiana 82,835 3.4 .2 .2 Iowa 36,810 5.6 .1 .1 Kansas 37,201 .8 3.7 1.4 Kentucky 52,377 7.4 3.2 4.9 Louisiana 65,641 6.0 .1 .1 Maine 13,896 2.6 .2 .4 Maryland 72,396 13.0 .0 .1 Massachusetts 81,648 .8 .4 .6 Michigan 134,642 8.3 .2 .2 Minnesota 63,263 16.1 2.7 4.0 Mississippi 41,344 5.9 .2 .2 Missouri 73,028 3.7 .1 .1 Montana 11,142 1.0 .1 .1 Nebraska 23,243 1.4 .0 .0 Nevada 25,056 9.9 .3 .9 New Hampshire 14,665 4.6 .1 .1 New Jersey 114,828 18.4 .7 .9 New Mexico 26,920 8.8 .0 .0 New York 271,369 17.2 2.5 3.1 North Carolina 101,592 3.0 .0 .0 North Dakota 8,476 1.7 .1 .5 clsnat94.doc - Page 24 Table A. Percent of Birth Records on Which Specified Items Were Not Stated: United States and Each State, Puerto Rico, Virgin Islands, and Guam: 1995 [By place of residence] Complica- Number tions of Area of Weight Obstetric labor and/ births gain procedures or delivery Total of reporting areas 1/ 3,899,589 9.0 0.8 1.0 Ohio 154,064 4.4 .2 .2 Oklahoma 45,672 30.7 22.3 25.5 Oregon 42,811 2.8 .0 .0 Pennsylvania 151,850 4.3 .0 .1 Rhode Island 12,776 8.1 4.8 4.9 South Carolina 50,926 1.8 .0 .0 South Dakota 10,475 2.3 .2 .2 Tennessee 73,173 3.2 .0 .1 Texas 322,753 18.6 .1 9/.1 Utah 39,577 1.9 .0 .1 Vermont 6,783 1.5 .1 .1 Virginia 92,578 5.2 .1 .1 Washington 77,228 17.2 .1 .1 West Virginia 21,162 7.1 .2 .5 Wisconsin 67,479 1.2 .0 .1 Wyoming 6,261 1.6 .0 .0 Puerto Rico 63,419 .2 .1 .1 Virgin Islands 2,032 15.6 12.0 27.5 Guam 4,179 25.6 2.3 2.9 1/ Excludes data for Puerto Rico, Virgin Islands, and Guam. 2/ California reports date last normal menses began but does not report clinical estimate of gestation. 3/ Kansas does not report Rh sensitization. 4/ New York city (but not New York State) reports tobacco use. 5/ Texas does not report genital herpes and uterine bleeding. 6/ Massachusetts, Nebraska, and Texas do not report birth injury. 7/ New York city does not report assisted ventilation less than 30 minutes and assisted ventilation of 30 minutes or more. 8/ New York State (but not New York city) reports congenital anomalies. 9/ Texas does not report anesthetic complications and fetal distress. 10/ Wisconsin does not report fetal alcohol syndrome. clsnat94.doc - Page 25 Table A. Percent of Birth Records on Which Specified Items Were Not Stated: United States and Each State, Puerto Rico, Virgin Islands, and Guam: 1995 [By place of residence] Abnormal Number Method condi- Area of of tions of Congenital births delivery newborn anomalies Total of reporting areas 1/ 3,899,589 0.7 1.3 1.6 Alabama 60,329 0.1 0.5 0.0 Alaska 10,244 .3 .2 .2 Arizona 72,463 .3 .0 .4 Arkansas 35,175 .7 .6 1.0 California 552,045 .0 .1 .1 Colorado 54,332 .0 .0 .1 Connecticut 44,334 7.9 20.1 21.9 Delaware 10,266 .0 .0 .1 Dist. of Columbia 9,014 .0 .0 .0 Florida 188,723 .4 .0 .0 Georgia 112,282 .1 .0 .0 Hawaii 18,595 1.4 1.3 1.2 Idaho 18,035 .3 5.8 5.8 Illinois 185,812 .3 .1 .1 Indiana 82,835 .3 .4 .2 Iowa 36,810 .4 .2 .2 Kansas 37,201 3.1 1.4 1.4 Kentucky 52,377 3.5 5.4 4.9 Louisiana 65,641 .1 .1 .1 Maine 13,896 .6 .7 .6 Maryland 72,396 .2 .1 .2 Massachusetts 81,648 .4 6/1.0 .9 Michigan 134,642 .7 .3 .2 Minnesota 63,263 2.5 5.5 5.8 Mississippi 41,344 .2 .2 .2 Missouri 73,028 .4 .1 .1 Montana 11,142 .3 .1 .1 Nebraska 23,243 .2 6/.0 .0 Nevada 25,056 .7 1.9 2.0 New Hampshire 14,665 .2 .1 .1 New Jersey 114,828 .5 2.5 4.2 New Mexico 26,920 .5 .0 ... New York 271,369 .9 7/2.7 8/9.3 North Carolina 101,592 .3 .0 .0 North Dakota 8,476 .2 .6 .6 clsnat94.doc - Page 26 Table A. Percent of Birth Records on Which Specified Items Were Not Stated: United States and Each State, Puerto Rico, Virgin Islands, and Guam: 1995 [By place of residence] Abnormal Number Method condi- Area of of tions of Congenital births delivery newborn anomalies Total of reporting areas 1/ 3,899,589 0.7 1.3 1.6 Ohio 154,064 .4 .2 .3 Oklahoma 45,672 18.8 30.3 31.0 Oregon 42,811 .2 .0 .0 Pennsylvania 151,850 .3 .3 .4 Rhode Island 12,776 .3 12.9 13.3 South Carolina 50,926 .4 .0 .0 South Dakota 10,475 .2 .3 .3 Tennessee 73,173 .5 .1 .1 Texas 322,753 .5 6/.1 .1 Utah 39,577 .2 .3 .6 Vermont 6,783 .1 .1 .2 Virginia 92,578 .4 .8 .1 Washington 77,228 .3 .1 .1 West Virginia 21,162 .2 .9 .6 Wisconsin 67,479 .1 10/.1 .1 Wyoming 6,261 .1 .0 .1 Puerto Rico 63,419 .0 .0 .0 Virgin Islands 2,032 4.4 31.7 31.5 Guam 4,179 2.5 2.2 2.1 1/ Excludes data for Puerto Rico, Virgin Islands, and Guam. 2/ California reports date last normal menses began but does not report clinical estimate of gestation. 3/ Kansas does not report Rh sensitization. 4/ New York city (but not New York State) reports tobacco use. 5/ Texas does not report genital herpes and uterine bleeding. 6/ Massachusetts, Nebraska, and Texas do not report birth injury. 7/ New York city does not report assisted ventilation less than 30 minutes and assisted ventilation of 30 minutes or more. 8/ New York State (but not New York city) reports congenital anomalies. 9/ Texas does not report anesthetic complications and fetal distress. 10/ Wisconsin does not report fetal alcohol syndrome. clsnat94.doc - Page 27 Definitions of medical terms (continued) Anesthetic complications--Any complication during labor and/or delivery brought on by an anesthetic agent or agents. Fetal distress--Signs indicating fetal hypoxia (deficiency in amount of oxygen reaching fetal tissues). Abnormal conditions of the newborn This item provides information on eight specific abnormal conditions. More than one abnormal condition may be reported for a given birth or "None" may be selected. If the item is not completed it is tabulated as "not stated." This item was included on the birth certificates of all States and the District of Columbia in 1994. However, several States did not include all conditions (see table A). The following definitions are adapted and abbreviated from a set of definitions compiled by a committee of Federal and State health statistics officials for the Association for Vital Records and Health Statistics (14). Definitions of medical terms Anemia--Hemoglobin level of less than 13.0 g/dL or a hematocrit of less than 39 percent. Birth injury--Impairment of the infant's body function or structure due to adverse influences that occurred at birth. Fetal alcohol syndrome--A syndrome of altered prenatal growth and development occurring in infants born of women who consumed excessive amounts of alcohol during pregnancy. Hyaline membrane disease/RDS--A disorder primarily of prematurity, manifested clinically by respiratory distress and pathologically by pulmonary hyaline membranes and incomplete expansion of the lungs at birth. Meconium aspiration syndrome--Aspiration of meconium by the fetus or newborn, affecting the lower respiratory system. Assisted ventilation (less than 30 minutes)--A mechanical method of assisting respiration for newborns with respiratory failure. Assisted ventilation (30 minutes or more)--Newborn placed on assisted ventilation for 30 minutes or longer. Seizures--A seizure of any etiology. Congenital anomalies of child The data provided in this item relate to 21 specific anomalies or anomaly groups. It is well documented that congenital anomalies, except for the most visible and most severe, are incompletely reported on birth certificates. The completeness of reporting specific anomalies depends on how easily they are recognized in the short time between birth and birth registration. Forty-nine States and the District of Columbia included this item on their birth certificates (New Mexico and New York City did not). This reporting area included 96 percent of all births in the United States in 1994. The format allows for the identification of more than one anomaly including a choice of "None" should no anomalies be evident. The category "not stated" includes birth records for which the item is not completed. clsnat94.doc - Page 28 The following definitions are adapted and abbreviated from a set of definitions compiled by a committee of Federal and State health statistics officials for the Association for Vital Records and Health Statistics (14). Definitions of medical terms Anencephalus--Absence of the cerebral hemispheres. Spina Bifida/meningocele--Developmental anomaly characterized by defective closure of the bony encasement of the spinal cord, through which the cord and meninges may or may not protrude. Hydrocephalus--Excessive accumulation of cerebrospinal fluid within the ventricles of the brain with consequent enlargement of the cranium. Microcephalus--A significantly small head. Other central nervous system anomalies--Other specified anomalies of the brain, spinal cord, and nervous system. Heart malformations--Congenital anomalies of the heart. Other circulatory/respiratory anomalies--Other specified anomalies of the circulatory and respiratory systems. Rectal atresia/stenosis--Congenital absence, closure, or narrowing of the rectum. Tracheo-esophageal fistula/Esophageal atresia--An abnormal passage between the trachea and the esophagus; esophageal atresia is the congenital absence or closure of the esophagus. Omphalocele/gastroschisis--An omphalocele is a protrusion of variable amounts of abdominal viscera from a midline defect at the base of the umbilicus. In gastroschisis, the abdominal viscera protrude through an abdominal wall defect, usually on the right side of the umbilical cord insertion. Other gastrointestinal anomalies--Other specified congenital anomalies of the gastrointestinal system. Malformed genitalia--Congenital anomalies of the reproductive organs. Renal agenesis--One or both kidneys are completely absent. Other urogenital anomalies--Other specified congenital anomalies of the organs concerned in the production and excretion of urine, together with organs of reproduction. Cleft lip/palate--Cleft lip is a fissure of elongated opening of the lip; cleft palate is a fissure in the roof of the mouth. These are failures of embryonic development. Polydactyly/syndactyly/adactyly--Polydactyly is the presence of more than five digits on either hands and/or feet; syndactyly is having fused or webbed fingers and/or toes; adactyly is the absence of fingers and/or toes. Club foot--Deformities of the foot, which is twisted out of shape or position. Diaphragmatic hernia--Herniation of the abdominal contents through the diaphragm into the thoracic cavity usually resulting in respiratory distress. Other musculoskeletal/integumental anomalies--Other specified congenital anomalies of the muscles, skeleton, or skin. Down's syndrome--The most common chromosomal defect with most cases resulting from an extra chromosome (trisomy 21). Other chromosomal anomalies--All other chromosomal aberrations. clsnat94.doc - Page 29 Method of delivery The new birth certificate contains a checkbox item on method of delivery. The choices include vaginal delivery, with the additional options of forceps, vacuum, and vaginal birth after previous cesarean section (VBAC), as well as a choice of primary or repeat cesarean. When only forceps, vacuum, or VBAC is checked, a vaginal birth is assumed. In 1994 this information was collected from the birth certificates of all States and the District of Columbia. Several rates are computed for method of delivery. The overall cesarean section rate or total cesarean rate is computed as the proportion of all births that were delivered by cesarean section. The primary cesarean rate is a measure that relates the number of women having a primary cesarean delivery to all women giving birth who have never had a cesarean delivery. The denominator for this rate includes all births, less those with method of delivery classified as repeat cesareans and vaginal birth after previous cesarean. The repeat cesarean rate is the proportion of all cesarean deliveries that were to women having their second (or subsequent) cesarean delivery. The rate for vaginal birth after previous cesarean (VBAC) delivery is computed by relating all VBAC deliveries to the sum of VBAC and repeat cesarean deliveries, that is, to women with a previous cesarean section. Repeat cesarean and VBAC rates for first births exist because the rates are computed on the basis of previous pregnancies, not just live births. Hispanic parentage The 1989 revision of the U.S. Standard Certificate of Live Births includes items to identify the Hispanic origin of the parents. Concurrent with the 1978 revision of the U.S. Certificate of Live Birth, NCHS recommended that items to identify the Hispanic or ethnic origin of the newborn's parents be included on birth certificates and has tabulated and evaluated these data from the reporting States. All 50 States and the District of Columbia reported Hispanic origin of the parents for 1994. In computing birth and fertility rates for the Hispanic population, births with origin of mother not stated are included with non-Hispanic births rather than being distributed. Thus, rates for the Hispanic population are underestimates of the true rates to the extent that the births with origin mother not stated (1.1 percent in 1994) were actually to Hispanic mothers. The population with origin not stated was imputed. The effect on the rates is believed to be small. clsnat94.doc - Page 30