Infant Mortality by Selected Maternal Characteristics and Race and Hispanic Origin in the United States, 2019-2021.

Objectives- This report presents infant mortality rates for selected maternal characteristics (prepregnancy body mass index, cigarette smoking during pregnancy, receipt of Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) benefits during pregnancy, timing of prenatal care, and source of payment for delivery) for the five largest maternal race and Hispanic-origin groups in the United States for combined years 2019-2021. Methods-Descriptive tabulations based on data from the linked birth/infant death files for 2019-2021 are presented. The linked birth/infant death file is based on birth and death certificates registered in all 50 states and the District of Columbia. Infant mortality rates are presented for each maternal race and Hispanic-origin group overall and by selected characteristics. Results-Infant mortality rates varied across the five largest maternal race and Hispanic-origin groups and by selected maternal characteristics. For most race and Hispanic-origin groups, mortality rates were higher among infants of women with prepregnancy obesity compared with those of women who were normal weight, and were higher for infants of women who smoked cigarettes during pregnancy, received late or no prenatal care, or were covered by Medicaid as the source of payment for delivery. Overall, mortality rates were higher for infants of women who received WIC during pregnancy, but results varied across race and Hispanic-origin groups. Mortality rates for the maternal characteristics examined were generally highest among infants of Black non-Hispanic and American Indian and Alaska Native non-Hispanic women and lowest for Asian non-Hispanic women.

Infant Mortality in the United States, 2022: Data From the Period Linked Birth/Infant Death File.

Objectives: This report presents final 2022 infant mortality statistics by age at death, maternal race and Hispanic origin, maternal age, gestational age, leading causes of death, and maternal state of residence. Trends in infant mortality are also examined. Methods: Descriptive tabulations of data are presented and interpreted for infant deaths and infant mortality rates using the 2022 period linked birth/infant death file. The linked birth/infant death file is based on birth and death certificates registered in all 50 states and the District of Columbia. Results: A total of 20,577 infant deaths were reported in the United States in 2022, up 3% from 2021. The U.S. infant mortality rate was 5.61 infant deaths per 1,000 live births, a 3% increase from the rate of 5.44 in 2021. The neonatal mortality rate increased 3% from 3.49 in 2021 to 3.59 in 2022, and the postneonatal mortality rate increased 4% from 1.95 to 2.02. The overall infant mortality rate increased for infants of American Indian and Alaska Native non-Hispanic, White non-Hispanic, and Dominican women in 2022 compared with 2021; changes in rates for the other race and Hispanic-origin groups were not significant. Infants of Black non-Hispanic women had the highest mortality rate (10.90) in 2022, followed by infants of American Indian and Alaska Native non-Hispanic and Native Hawaiian or Other Pacific Islander non-Hispanic (9.06 and 8.50, respectively), Hispanic (4.89), White non-Hispanic (4.52), and Asian non-Hispanic (3.51) women. Mortality rates increased from 2021 to 2022 among preterm (less than 37 weeks of gestation) infants (33.59 to 34.78) and for infants born term (37 to 41 weeks of gestation) (2.08 to 2.18). The five leading causes of infant death in 2022 were the same as in 2021. Infant mortality rates by state for 2022 ranged from a low of 3.32 in Massachusetts to a high of 9.11 in Mississippi.

Changes in First and Second Births to U.S. Teenagers From 2000 to 2022.

Objectives: This study examines trends in the numbers, percentages, and rates of first and second and higher-order births to teenagers younger than age 20 and for those ages 15-17 and 18-19 by race and Hispanic origin. Methods: Data for this analysis are from the National Vital Statistics System birth data files from 2000 and 2022. Analyses are limited to births to females younger than age 20. Changes in the numbers, percentages, and rates of total, first, and second and higher-order teen births from 2000 to 2022 were calculated for all teenagers and for non-Hispanic American Indian and Alaska Native, non-Hispanic Black, non-Hispanic White, and Hispanic teenagers. Results: The number of first teen births declined 67% and the number of second and higher-order teen births declined 79%, while the population of female teenagers increased 7% from 2000 to 2022. The declines were greater for younger teenagers compared with older teenagers. First and second and higher-order teen birth rates declined 69% and 80%, respectively. Similar declines were found for each race and Hispanic-origin group. In 2000 and 2022, first and second and higher-order birth rates were lowest among White teenagers. First birth rates were highest among Hispanic teenagers in 2000 and for Hispanic and non-Hispanic American Indian and Alaska Native teenagers in 2022. In 2000, second and higher-order birth rates were highest for non-Hispanic Black and Hispanic teenagers; second and higher-order birth rates were more similar by race and Hispanic-origin group in 2022.

Births: Final Data for 2022.

Objectives- This report presents 2022 data on U.S. births by selected characteristics. Trends in fertility patterns and maternal and infant characteristics are described. Methods-Descriptive tabulations based on birth certificates of the 3.67 million births registered in 2022 are shown by maternal age, live-birth order, race and Hispanic origin, marital status, tobacco use, prenatal care, source of payment for the delivery, method of delivery, gestational age, birthweight, and plurality. Selected data by mother's state of residence and birth rates also are shown. Trends for 2010 to 2022 are presented for selected items, and by race and Hispanic origin for 2016-2022. Results-A total of 3,667,758 births occurred in the United States in 2022, essentially unchanged from 2021. The general fertility rate declined 1% from 2021 to 56.0 births per 1,000 females ages 15-44 in 2022. The birth rate for females ages 15-19 declined 2% from 2021 to 2022; birth rates fell 7% for women ages 20-24, rose 1% to 5% for women ages 25-29 and 35-44, and rose 12% for women ages 45-49 (the first increase since 2016). The total fertility rate declined less than 1% to 1,656.5 births per 1,000 women in 2022. Birth rates declined for unmarried women but increased for married women from 2021 to 2022. Prenatal care beginning in the first trimester declined to 77.0% in 2022; the percentage of women who smoked during pregnancy declined to 3.7%. The cesarean delivery rate was unchanged in 2022 (32.1%); Medicaid was the source of payment for 41.3% of births. The preterm birth rate declined 1% to 10.38%; the low birthweight rate rose 1% to 8.60%. The twin birth rate was unchanged in 2022 (31.2 per 1,000 births); the 2% decrease in the triplet and higher-order multiple birth rate.

Maternal Characteristics and Infant Outcomes by Hispanic Subgroup and Nativity:United States, 2021.

Objectives-This report presents comparisons of maternal characteristics and infant outcomes of Hispanic women and their infants by nativity (whether they were born in or outside the United States) for all Hispanic women and for the six largest Hispanic subgroups by nativity.

Infant Mortality in the United States, 2021: Data From the Period Linked Birth/Infant Death File.

Objective-This report presents 2021 infant mortality statistics by age at death, maternal race and Hispanic origin, maternal age, gestational age, leading causes of death, and maternal state of residence. Trends in infant mortality are also examined. Methods-Descriptive tabulations of data are presented and interpreted for infant deaths and infant mortality rates using the 2021 period linked birth/infant death file. The linked birth/infant death file is based on birth and death certificates registered in all 50 states and the District of Columbia. Results-A total of 19,928 infant deaths were reported in the United States in 2021, up 2% from 2020. The U.S. infant mortality rate was 5.44 infant deaths per 1,000 live births, essentially unchanged from the rate of 5.42 in 2020. The neonatal mortality rate was essentially unchanged from 3.56 in 2020 to 3.49 in 2021, but the postneonatal mortality rate increased from 1.86 to 1.95. The overall infant mortality rate increased for infants of Asian non-Hispanic women and declined for infants of Dominican women in 2021 compared with 2020; changes in rates for the other race and Hispanic-origin groups were not significant. Infants of Black non-Hispanic women had the highest mortality rate (10.55) in 2021, followed by infants of Native Hawaiian or Pacific Islander non-Hispanic and American Indian or Alaska Native non-Hispanic (7.76 and 7.46, respectively), Hispanic (4.79), White non-Hispanic (4.36), and Asian non-Hispanic (3.69) women. By gestational age, infants born very preterm (less than 28 weeks of gestation) had the highest mortality rate (353.76), 170 times as high as that for infants born at term (37-41 weeks of gestation) (2.08). The five leading causes of infant death in 2021 were the same as in 2020. Infant mortality rates by state for 2021 ranged from a low of 2.77 in North Dakota to a high of 9.39 in Mississippi.

Homicides Among Infants in the United States,2017-2020.

Objectives-This report describes homicide rates among infants (under age 1 year) by selected maternal, pregnancy-related, and infant characteristics. Methods-Linked birth/infant death files based on data collected on U.S. birth and death certificates were used to calculate homicide rates among infants for the period 2017-2020. Results-A total of 1,067 homicides occurred among infants in the United States from 2017 through 2020, an average of 267 per year. More than one-half of all infant homicides occurred among infants aged 3 months and under. Homicide rates were higher among infants born to mothers who were young, had multiple previous live births, were Black non-Hispanic, were born in the United States, had lower levels of education, lived in rural areas, had no prenatal care, and delivered outside of a hospital. Rates were also higher for infants who were part of a multiple-gestation pregnancy, were born preterm or low birthweight, or were admitted to a neonatal intensive care unit.

Births: Final Data for 2021.

Objectives-This report presents 2021 data on U.S. births according to a variety of characteristics. Trends in fertility patterns and maternal and infant characteristics are described and interpreted.

Infant Mortality in the United States, 2020: Data From the Period Linked Birth/Infant Death File.

Objectives-This report presents 2020 infant mortality statistics by age at death, maternal race and Hispanic origin, maternal age, gestational age, leading causes of death, and maternal state of residence. Trends in infant mortality are also examined.

The changing risk and burden of wildfire in the United States.

Recent dramatic and deadly increases in global wildfire activity have increased attention on the causes of wildfires, their consequences, and how risk from wildfire might be mitigated. Here we bring together data on the changing risk and societal burden of wildfire in the United States. We estimate that nearly 50 million homes are currently in the wildland-urban interface in the United States, a number increasing by 1 million houses every 3 y. To illustrate how changes in wildfire activity might affect air pollution and related health outcomes, and how these linkages might guide future science and policy, we develop a statistical model that relates satellite-based fire and smoke data to information from pollution monitoring stations. Using the model, we estimate that wildfires have accounted for up to 25% of PM2.5 (particulate matter with diameter <2.5 µm) in recent years across the United States, and up to half in some Western regions, with spatial patterns in ambient smoke exposure that do not follow traditional socioeconomic pollution exposure gradients. We combine the model with stylized scenarios to show that fuel management interventions could have large health benefits and that future health impacts from climate-change-induced wildfire smoke could approach projected overall increases in temperature-related mortality from climate change-but that both estimates remain uncertain. We use model results to highlight important areas for future research and to draw lessons for policy.

Infant Mortality in the United States, 2019:Data From the Period Linked Birth/Infant Death File.

Objectives-This report presents 2019 infant mortality statistics by age at death, maternal race and Hispanic origin, maternal age, gestational age, leading causes of death, and maternal state of residence. Trends in infant mortality are also examined.

Prepregnancy Body Mass Index and Infant Outcomes by Race and Hispanic Origin: United States, 2020.

Objectives-This report presents data on distributions in prepregnancy body mass index (BMI), including the three classes of obesity, by maternal race and Hispanic origin for women who gave birth in 2020. It also examines newborn outcomes by BMI by maternal race and Hispanic origin.

Births: Final Data for 2019.

Objectives-This report presents 2019 data on U.S. births according to a wide variety of characteristics. Trends in fertility patterns and maternal and infant characteristics are described and interpreted. Methods-Descriptive tabulations of data reported on the birth certificates of the 3.75 million births that occurred in 2019 are presented. Data are presented for maternal age, livebirth order, race and Hispanic origin, marital status, tobacco use, prenatal care, source of payment for the delivery, method of delivery, gestational age, birthweight, and plurality. Selected data by mother's state of residence and birth rates by age are also shown. Trend data for 2010 through 2019 are presented for selected items. Trend data by race and Hispanic origin are shown for 2016-2019. Results-A total of 3,747,540 births were registered in the United States in 2019, down 1% from 2018. The general fertility rate declined from 2018 to 58.3 births per 1,000 women aged 15-44 in 2019. The birth rate for females aged 15-19 fell 4% between 2018 and 2019. Birth rates declined for women aged 20-34 and increased for women aged 35-44 for 2018-2019. The total fertility rate declined to 1,706.0 births per 1,000 women in 2019. Birth rates declined for both married and unmarried women from 2018 to 2019. The percentage of women who began prenatal care in the first trimester of pregnancy rose to 77.6% in 2019; the percentage of all women who smoked during pregnancy declined to 6.0%. The cesarean delivery rate decreased to 31.7% in 2019 (Figure 1). Medicaid was the source of payment for 42.1% of all births in 2019. The preterm birth rate rose for the fifth straight year to 10.23% in 2019; the rate of low birthweight was essentially unchanged from 2018 at 8.31%. Twin and triplet and higher-order multiple birth rates both declined in 2019 compared with 2018.

Births: Final Data for 2020.

Objectives-This report presents 2020 data on U.S. births according to a wide variety of characteristics. Trends in fertility patterns and maternal and infant characteristics are described and interpreted.

Infant Mortality in the United States, 2018: Data From the Period Linked Birth/Infant Death File.

Objectives-This report presents 2018 infant mortality statistics by age at death, maternal race and Hispanic origin, maternal age, gestational age, leading causes of death, and maternal state of residence. Trends in infant mortality are also examined. Methods-Descriptive tabulations of data are presented and interpreted for infant deaths and infant mortality rates using the 2018 period linked birth/infant death file; the linked birth/infant death file is based on birth and death certificates registered in all states and the District of Columbia. Results-A total of 21,498 infant deaths were reported in the United States in 2018. The U.S. infant mortality rate was 5.67 infant deaths per 1,000 live births, lower than the rate of 5.79 in 2017 and an historic low in the country. The neonatal and post neonatal mortality rates for 2018 (3.78 and 1.89, respectively) demonstrated a nonsignificant decline compared with 2017 (3.85 and 1.94, respectively). The 2018 mortality rate declined for infants of Hispanic women compared with the 2017 rate; changes in rates for other race and Hispanic-origin groups were not statistically significant. The 2018 infant mortality rate for infants of non-Hispanic black women (10.75) was more than twice as high as that for infants of non-Hispanic white (4.63), non-Hispanic Asian (3.63), and Hispanic women (4.86). Infants born very preterm (less than 28 weeks of gestation) had the highest mortality rate (382.20), 186 times as high as that for infants born at term (37-41 weeks of gestation) (2.05). The five leading causes of infant death in 2018 were the same as in 2017; cause-of-death rankings and mortality rates varied by maternal race and Hispanic origin. Infant mortality rates by state for 2018 ranged from a low of 3.50 in New Hampshire to a high of 8.41 in Mississippi.

Effects of Changes in Maternal Age Distribution and Maternal Age-specific Infant Mortality Rates on Infant Mortality Trends: United States, 2000-2017.

Objectives-This report assesses the contributions of the changing maternal age distribution and maternal age-specific infant mortality rates on overall and race and Hispanic origin-specific infant mortality rates in the United States from 2000 to 2017. Methods-The analyses used 2000-2017 linked birth and infant death data from the National Vital Statistics System. Age-adjusted infant mortality rates, based on the 2000 U.S. maternal age distribution, were calculated for each year. These rates were compared with crude rates for all births and for specific race and Hispanic-origin groups. Decomposition analysis was used to estimate the proportion of the decline due to changes in maternal age distribution and in age-specific mortality rates. Results-During 2000-2017, the age of women giving birth rose as infant mortality rates declined, although unevenly across maternal age groups. The maternal age-adjusted infant mortality rate in 2017 was 6.13 compared with the crude rate of 5.79, resulting in a 0.34 percentage point difference. Changes in the maternal age distribution accounted for 31.3% of the decline in infant mortality rates for all births and for births to non-Hispanic white women, and for 4.8% of the decline in births to non-Hispanic black women. Declines in age-specific mortality rates accounted for the remainder of the decline for these groups and for all of the decline in births to Hispanic women. Conclusion-Changes in the age distribution of women giving birth accounted for about one-third of the decline in infant mortality rates from 2000 through 2017; declines in maternal age-specific mortality rates accounted for about two-thirds of this decline. These patterns varied by race and Hispanic origin.

Daily Local-Level Estimates of Ambient Wildfire Smoke PM2.5 for the Contiguous US.

Smoke from wildfires is a growing health risk across the US. Understanding the spatial and temporal patterns of such exposure and its population health impacts requires separating smoke-driven pollutants from non-smoke pollutants and a long time series to quantify patterns and measure health impacts. We develop a parsimonious and accurate machine learning model of daily wildfire-driven PM2.5 concentrations using a combination of ground, satellite, and reanalysis data sources that are easy to update. We apply our model across the contiguous US from 2006 to 2020, generating daily estimates of smoke PM2.5 over a 10 km-by-10 km grid and use these data to characterize levels and trends in smoke PM2.5. Smoke contributions to daily PM2.5 concentrations have increased by up to 5 µg/m3 in the Western US over the last decade, reversing decades of policy-driven improvements in overall air quality, with concentrations growing fastest for higher income populations and predominantly Hispanic populations. The number of people in locations with at least 1 day of smoke PM2.5 above 100 µg/m3 per year has increased 27-fold over the last decade, including nearly 25 million people in 2020 alone. Our data set can bolster efforts to comprehensively understand the drivers and societal impacts of trends and extremes in wildfire smoke.

Associations between wildfire smoke exposure during pregnancy and risk of preterm birth in California.

There is limited population-scale evidence on the burden of exposure to wildfire smoke during pregnancy and its impacts on birth outcomes. In order to investigate this relationship, data on every singleton birth in California 2006-2012 were combined with satellite-based estimates of wildfire smoke plume boundaries and high-resolution gridded estimates of surface PM2.5 concentrations and a regression model was used to estimate associations with preterm birth risk. Results suggest that each additional day of exposure to any wildfire smoke during pregnancy was associated with an 0.49 % (95 % CI: 0.41-0.59 %) increase in risk of preterm birth (<37 weeks). At sample median smoke exposure (7 days) this translated to a 3.4 % increase in risk, relative to an unexposed mother. Estimates by trimester suggest stronger associations with exposure later in pregnancy and estimates by smoke intensity indicate that observed associations were driven by higher intensity smoke-days. Exposure to low intensity smoke-days had no association with preterm birth while an additional medium (smoke PM2.5 5-10 µg/m3) or high (smoke PM2.5 > 10 µg/m3) intensity smoke-day was associated with an 0.95 % (95 % CI: 0.47-1.42 %) and 0.82 % (95 % CI: 0.41-1.24 %) increase in preterm risk, respectively. In contrast to previous findings for other pollution types, neither exposure to smoke nor the relative impact of smoke on preterm birth differed by race/ethnicity or income in our sample. However, impacts differed greatly by baseline smoke exposure, with mothers in regions with infrequent smoke exposure experiencing substantially larger impacts from an additional smoke-day than mothers in regions where smoke is more common. We estimate 6,974 (95 % CI: 5,513-8,437) excess preterm births attributable to wildfire smoke exposure 2007-2012, accounting for 3.7 % of observed preterm births during this period. Our findings have important implications for understanding the costs of growing wildfire smoke exposure, and for understanding the benefits of smoke mitigation measures.

Infant Mortality in the United States, 2017: Data From the Period Linked Birth/Infant Death File.

Objectives-This report presents 2017 infant mortality statistics by age at death, maternal race and Hispanic origin, maternal age, maternal state of residence, gestational age, and leading causes of death. Trends in infant mortality are also examined. Methods-Descriptive tabulations of data are presented and interpreted for infant deaths and infant mortality rates using the 2017 period linked birth/infant death file; the linked birth/infant death file is based on birth and death certificates registered in all states and the District of Columbia. Results-A total of 22,341 infant deaths were reported in the United States in 2017. The U.S. infant mortality rate was 5.79 infant deaths per 1,000 live births, not statistically different from the rate of 5.87 in 2016. The neonatal and postneonatal mortality rates for 2017 (3.85 and 1.94, respectively) were also essentially unchanged from 2016. The 2017 infant mortality rate for infants of non-Hispanic black women (10.97) was more than twice as high as that for infants of non-Hispanic white (4.67), non-Hispanic Asian (3.78), and Hispanic (5.10) women. Infant mortality rates by state for 2017 ranged from a low of 3.66 in Massachusetts to a high of 8.73 in Mississippi. Infants born very preterm (less than 28 weeks of gestation) had the highest mortality rate (384.39), 183 times as high as that for infants born at term (37-41 weeks of gestation) (2.10). The five leading causes of infant death in 2017 were the same as in 2016; cause of death rankings and mortality rates varied by maternal race and Hispanic origin. Preterm-related causes of death accounted for 34% of the 2017 infant deaths, unchanged from 2016.

Maternal Characteristics and Infant Outcomes in Appalachia and the Delta.

Objectives-This report compares maternal characteristics and outcomes for infants born to mothers in Appalachia, the Delta, and the rest of the United States. Methods-The 2017 vital statistics natality file and the 2016-2017 linked birth/infant death data files were used to compare maternal characteristics (e.g., race and Hispanic origin, age, and marital status) of women who gave birth in Appalachia, the Delta, and the rest of the United States. Comparisons of infant outcomes (preterm, low birthweight, and infant mortality) across the three regions were made overall and within categories of these maternal characteristics. Results-Characteristics of women who gave birth differed across the three regions. Women in the Delta were most likely to be teenagers, unmarried, and not have a college degree, followed by women in Appalachia, and then by women in the rest of the United States. Overall and within most categories of maternal characteristics, infants born in the Delta were more likely to be preterm (12.37%) or low birthweight (10.75%) and were more likely to die in their first year of life (8.17 infant deaths per 1,000 live births) than those born in Appalachia (10.75%, 8.87%, and 6.82, respectively), while those born in the rest of the United States were the least likely (9.78%, 8.14%, and 5.67, respectively). Conclusions-Maternal characteristics associated with poor infant outcomes are most common among women who give birth in the Delta, followed by women in Appalachia, and then the rest of the United States. Within most categories of these maternal characteristics, infants born in the Delta have the worst outcomes, followed by those born in Appalachia, and then those born in the rest of the United States.