Trends and Variations in Reproduction and Intrinsic Rates: United States, 1990-2014.

Objective-This report presents trends in reproduction and intrinsic rates from 1990 through 2014. In addition, total fertility and gross reproduction rates by race and Hispanic-origin group are presented from 1990 through 2014, and net reproduction and intrinsic rates for selected race and Hispanic-origin group are presented from 2006 through 2014. Methods-Tabular and graphic data on the trends in the reproduction and intrinsic rates for the United States, by race and Hispanic origin of mother, are presented and described. Results-Rates of reproduction (total fertility, gross reproduction, and net reproduction), the intrinsic rate of natural increase, and the intrinsic birth rate were lower in 2014 than 1990. After a steady decline from 1990 through 1997, all rates increased from 1997 through 2007 but declined again from 2007 through 2013. The rates increased between 2013 and 2014. Among the race and Hispanic subgroups examined, the total fertility and gross reproduction rates were lower for all groups in 2014 compared with 1990. The net reproduction rate, intrinsic rate of natural increase, and intrinsic birth rate for the selected groups non-Hispanic white, non-Hispanic black, and Hispanic declined from 2006 through 2014.

Prepregnancy Body Mass Index by Maternal Characteristics and State: Data From the Birth Certificate, 2014.

Objectives-This report describes prepregnancy body mass index (BMI) among women giving birth in 2014 for the 47-state and District of Columbia reporting areas that implemented the 2003 U.S. Standard Certificate of Live Birth by January 1, 2014.

Short Interpregnancy Intervals in 2014: Differences by Maternal Demographic Characteristics.

KEY FINDINGS: Data from the National Vital Statistics System •Nearly 29.0% of U.S. mothers who had a second or higher-order birth in 2014 had a short interpregnancy interval of less than 18 months. •Short intervals (i.e., less than 6 months, 6-11 months, and 12-17 months) were more common for mothers aged 35 and over (5.7%, 16.3%, and 22.1%, respectively) than mothers who were under age 20 at their previous birth (5.1%, 8.8%, and 8.4%). •Short intervals of less than 6 months and 6-11 months were more common among non-Hispanic black mothers (7.1% and 11.7%, respectively) than non-Hispanic white mothers (4.1% and 11.2%) and Hispanic mothers (5.0% and 9.3%). •The percentage of births to mothers with intervals less than 6 months decreased as education level increased, from 4.3% (no high school diploma) to 1.8% (doctorate or professional degree).

Measuring Gestational Age in Vital Statistics Data: Transitioning to the Obstetric Estimate.

Beginning with the 2014 data year, the National Center for Health Statistics is transitioning to a new standard for estimating the gestational age of a newborn. The new measure, the obstetric estimate of gestation at delivery (OE), replaces the measure based on the date of the last normal menses (LMP). This transition is being made because of increasing evidence of the greater validity of the OE compared with the LMP-based measure. This report describes the relationship between the two measures. Agreement between the two measures is shown for 2013. Comparisons between the two measures for single gestational weeks and selected gestational age categories for 2013, and trends in the two measures for 2007-2013 by gestational category, focusing on preterm births, are shown for the United States and by race and Hispanic origin and state.

Annual summary of vital statistics: 2009.

The number of births in the United States decreased by 3% between 2008 and 2009 to 4 130 665 births. The general fertility rate also declined 3% to 66.7 per 1000 women. The teenage birth rate fell 6% to 39.1 per 1000. Birth rates also declined for women 20 to 39 years and for all 5-year groups, but the rate for women 40 to 44 years continued to rise. The percentage of all births to unmarried women increased to 41.0% in 2009, up from 40.6% in 2008. In 2009, 32.9% of all births occurred by cesarean delivery, continuing its rise. The 2009 preterm birth rate declined for the third year in a row to 12.18%. The low-birth-weight rate was unchanged in 2009 at 8.16%. Both twin and triplet and higher order birth rates increased. The infant mortality rate was 6.42 infant deaths per 1000 live births in 2009. The rate is significantly lower than the rate of 6.61 in 2008. Linked birth and infant death data from 2007 showed that non-Hispanic black infants continued to have much higher mortality rates than non-Hispanic white and Hispanic infants. Life expectancy at birth was 78.2 years in 2009. Crude death rates for children and adolescents aged 1 to 19 years decreased by 6.5% between 2008 and 2009. Unintentional injuries and homicide, the first and second leading causes of death jointly accounted for 48.6% of all deaths to children and adolescents in 2009.

Fetal and perinatal mortality, United States, 2006.

OBJECTIVES: This report presents 2006 fetal and perinatal mortality data by maternal age, marital status, race, Hispanic origin, and state of residence, as well as by fetal birthweight, gestational age, plurality, and sex. Trends in fetal and perinatal mortality are also examined. METHODS: Descriptive tabulations of data are presented and interpreted. RESULTS: There were 25,972 reported fetal deaths at 20 weeks of gestation or more in the United States in 2006. The U.S. fetal mortality rate was 6.05 fetal deaths at 20 weeks of gestation or more per 1,000 live births, 3% lower than in 2005 (6.22). From 2005 to 2006, fetal mortality declined 3% for fetal deaths at 20-27 weeks of gestation, while the rate at 28 weeks or more did not decline significantly. This contrasts with the long-term trend of declines in fetal mortality at 28 weeks or more and stability at 20-27 weeks of gestation. Fetal mortality rates declined significantly for non-Hispanic black women from 2005 to 2006; however, rates for other racial and ethnic groups were essentially unchanged. In 2006, the fetal mortality rate for non-Hispanic black women (10.73) was more than twice the rate for non-Hispanic white (4.81) and Asian or Pacific Islander (4.89) women. The rate for American Indian or Alaska Native women (6.04) was 26% higher, and the rate for Hispanic women (5.29) was 10% higher, than the rate for non-Hispanic white women. Fetal mortality rates were higher than average for teenagers, women aged 35 and over, unmarried women, and women with multiple pregnancies.

Childbearing differences among three generations of U.S. women.

Each year a generation of women is born who will share similar sociohistorical experiences before and throughout their reproductive lives. These unique experiences can produce similar childbearing patterns in terms of the average number of children ever born--whether mothers are younger or older when their first birth occurs and the proportion of women who do not have children--that can differ from the patterns found for other cohorts. Childbearing patterns have profound consequences for society. These consequences include the demand for schools and housing, as well as women's participation in the labor force. Moreover, the lives of women who become mothers are significantly different from those who do not. Having children affects the acquisition of material goods and may impose costs for the mother in terms of personal and professional options. This report presents data on three selected birth cohorts of women representing generations born at 25-year intervals in 1910, 1935, and 1960, close to the average length of a generation in the United States. Data are from the cohort fertility tables, based on the National Vital Statistics System.

Transitions between childlessness and first birth: three generations of U.S. women.

OBJECTIVE: This report analyzes the patterns of childlessness, and conversely, the first-birth patterns of three birth cohorts of American women. For this report, a cohort refers to women born in the same year. The cohorts compared were women born in 1910, 1935, and 1960-who, consequently, turned 25 during the Great Depression, the Baby Boom, and lastly, the post-Baby Boom period. The purpose of the report is to explore the differences in fertility characteristics of these three generations of women and to consider those differences in light of the social and economic conditions at the time. METHODS: Life table methodology, including the probability of having a first birth, the number of women remaining childless, and the expected number of years to remain childless, was applied to each of the three birth cohorts for comparison. Techniques extended from life table functions were also used and included measures of first-birth concentration as well as comparisons between childlessness and the total fertility rate (TFR). Data were based on the Centers for Disease Control and Prevention's National Center for Health Statistics tables on cohort fertility. RESULTS: Of the three birth cohorts studied, the women born in 1910 had the highest proportion childless and a low TFR. In contrast, the women born in 1935 had both the lowest proportion childless and the highest TFR. The fertility of women who were born in 1960 is characterized as intermediate to the other cohorts in terms of childlessness, but is distinct with both lowest levels of childbearing and oldest ages of first births. First-time childbearing is more concentrated (that is, least spread out) by age of mother for the 1910 and 1935 cohorts than the 1960 cohort. Finally, data for all U.S. birth cohorts 1910-1960 suggest that the greater the proportion childless in a cohort; the lower the TFR.

Trends and differentials in higher-birthweight infants at 28-31 weeks of gestation, by race and Hispanic origin, United States, 1990-2002.

Birth certificate gestational age data based on the date of the mother's last menstrual period (LMP) are considered problematic. Of particular concern are birthweight distributions for infants reported on the birth certificate as having been delivered at 28-31 weeks' gestation; these distributions have been shown to be distinctly bimodal. The 'second curve' of the birthweight distribution at 28-31 weeks includes implausible birthweight/gestational age combinations and, thus, has been hypothesised to represent erroneous gestational ages due to misidentification of the date of LMP. It has been suggested that such 'misclassification' has declined in recent years and that this change can affect trends in preterm birth rates (<37 weeks' gestation), particularly rates among non-Hispanic black infants. This present study used primarily simple and multivariable analyses to review trends and differentials in birthweight distributions at 28-31 weeks by race and Hispanic origin of the mother. It aggregated data for the years 1990-92 and 2000-02 from the US vital statistics Natality files. Over the decade, the percentage of births in the second curve declined for all births and for each racial and Hispanic origin group studied. The largest decline was observed for non-Hispanic blacks; the smallest for Hispanic births. Later initiation of prenatal care, younger maternal age, lower educational attainment, higher birth order and vaginal and singleton delivery were positively associated with a larger second curve, suggesting misclassification of gestational age. Declines in the second curve over the study period were suggested to contribute significantly to the observed decrease in overall preterm birth rates for non-Hispanic black births. Further analysis is needed to estimate the influence of reporting error on preterm birth rates by race and Hispanic origin.