The relationship between obstetrical interventions and the increase in U.S. preterm births, 2014-2019.

We examined the relationship between obstetrical intervention and preterm birth in the United States between 2014 and 2019. This observational study analyzed 2014-2019 US birth data to assess changes in preterm birth, cesarean delivery, induction of labor, and associated risks. Logistic regression modeled the odds of preterm obstetrical intervention (no labor cesarean or induction) after risk adjustment. The percentage of singleton preterm births in the United States increased by 9.4% from 2014-2019. The percent of singleton, preterm births delivered by cesarean increased by 6.0%, while the percent with induction of labor increased by 39.1%. The percentage of singleton preterm births where obstetrical intervention (no labor cesarean or induction) potentially impacted the gestational age at delivery increased from 47.6% in 2014 to 54.9% in 2019. Preterm interventions were 13% more likely overall in 2019 compared to 2014 and 17% more likely among late preterm births, after controlling for demographic and medical risk factors. Compared to non-Hispanic White women, Non-Hispanic Black women had a higher risk of preterm obstetric interventions. Preterm infants have higher morbidity and mortality rates than term infants, thus any increase in the preterm birth rate is concerning. A renewed effort to understand the trends in preterm interventions is needed to ensure that obstetrical interventions are evidence-based and are limited to those cases where they optimize outcomes for both mothers and babies.

United States community births increased by 20% from 2019 to 2020.

BACKGROUND: Anecdotal and emerging evidence suggested that the 2020 COVID-19 pandemic may have influenced women's attitudes toward community birth. Our purpose was to examine trends in community births from 2019 to 2020, and the risk profile of these births. METHODS: Recently released 2020 birth certificate data were compared with prior years' data to analyze trends in community births by socio-demographic and medical characteristics. RESULTS: In 2020, there were 71 870 community births in the United States, including 45 646 home births and 21 884 birth center births. Community births increased by 19.5% from 2019 to 2020. Planned home births increased by 23.3%, while birth center births increased by 13.2%. Increases occurred in every US state, and for all racial and ethnic groups, particularly non-Hispanic Black mothers (29.7%), although not all increases were statistically significant. In 2020, 1 of every 50 births in the United States was a community birth (2.0%). Women with planned home and birth center births were less likely than women with hospital births to have several characteristics associated with poor pregnancy outcomes, including teen births, smoking during pregnancy, obesity, and preterm, low birthweight, and multiple births. More than two-thirds of planned home births were self-paid, compared with one-third of birth center and just 3% of hospital births. CONCLUSIONS: It is to the great credit of United States midwives working in home and birth center settings that they were able to substantially expand their services during a worldwide pandemic without compromising standards in triaging women to optimal settings for safe birth.

Racial and Ethnic Disparities in Maternal Mortality in the United States Using Enhanced Vital Records, 2016‒2017.

Objectives. To better understand racial and ethnic disparities in US maternal mortality. Methods. We analyzed 2016-2017 vital statistics mortality data with cause-of-death literals (actual words written on the death certificate) added. We created a subset of confirmed maternal deaths that had pregnancy mentions in the cause-of-death literals. Primary cause of death was identified and recoded using cause-of-death literals. We examined racial and ethnic disparities both overall and by primary cause. Results. The maternal mortality rate for non-Hispanic Black women was 3.55 times that for non-Hispanic White women. Leading causes of maternal death for non-Hispanic Black women were eclampsia and preeclampsia and postpartum cardiomyopathy with rates 5 times those for non-Hispanic White women. Non-Hispanic Black maternal mortality rates from obstetric embolism and obstetric hemorrhage were 2.3 to 2.6 times those for non-Hispanic White women. Together, these 4 causes accounted for 59% of the non-Hispanic Black‒non-Hispanic White maternal mortality disparity. Conclusions. The prominence of cardiovascular-related conditions among the leading causes of confirmed maternal death, particularly for non-Hispanic Black women, necessitates increased vigilance for cardiovascular problems during the pregnant and postpartum period. Many of these deaths are preventable.

Causes contributing to the excess maternal mortality risk for women 35 and over, United States, 2016-2017.

To better understand age-related disparities in US maternal mortality, we analyzed 2016-2017 vital statistics mortality data with cause-of-death literal text (actual words written on the death certificate) added. We created a subset of confirmed maternal deaths which had pregnancy mentions in the cause-of-death literals. Primary cause of death was identified and recoded using cause-of-death literals. Age-related disparities were examined both overall and by primary cause. Compared to women <35, the 2016-2017 US maternal mortality rate was twice as high for women aged 35-39, four times higher for women aged 40-44, and 11 times higher for women aged 45-54 years. Obstetric hemorrhage was the leading cause of death for women aged 35+ with rates 4 times higher than for women <35, followed by postpartum cardiomyopathy with a 3-fold greater risk. Obstetric embolism, eclampsia/preeclampsia, and Other complications of obstetric surgery and procedures each had a two-fold greater risk of death for women aged 35+. Together these 5 causes of death accounted for 70.9% of the elevated maternal mortality risk for women aged 35+. The excess maternal mortality risk for women aged 35+ was focused among a few causes of death and much of this excess mortality is preventable. Early detection and treatment, as well as continued care during the postpartum year is critical to preventing these deaths. The Alliance for Innovation on Maternal Health has promulgated patient safety bundles with specific interventions that health care systems can adopt in an effort to prevent these deaths.

Improving US maternal mortality reporting by analyzing literal text on death certificates, United States, 2016-2017.

Changes in data collection and processing of US maternal mortality data across states over time have led to inconsistencies in maternal death reporting. Our purpose was to identify possible misclassification of maternal deaths and to apply alternative coding methods to improve specificity of maternal causes. We analyzed 2016-2017 US vital statistics mortality data with cause-of-death literals (actual words written on the death certificate) added. We developed an alternative coding strategy to code the "primary cause of death" defined as the most likely cause that led to death. We recoded deaths with or without literal pregnancy mentions to maternal and non-maternal causes, respectively. Originally coded and recoded data were compared for overall maternal deaths and for a subset of deaths originally coded to ill-defined causes. Among 1691 originally coded maternal deaths, 597 (35.3%) remained a maternal death upon recoding and 1094 (64.7%) were recoded to non-maternal causes. The most common maternal causes were eclampsia and preeclampsia, obstetric embolism, postpartum cardiomyopathy, and obstetric hemorrhage. The most common non-maternal causes were diseases of the circulatory system and cancer, similar to the leading causes of death among all reproductive-age women (excluding injuries). Among 735 records originally coded to ill-defined causes, 94% were recoded to more specific, informative causes from literal text. Eighteen deaths originally coded as non-maternal mentioned pregnancy in the literals and were recoded as maternal deaths. Literal text provides more detailed information on cause of death which is often lost during coding. We found evidence of both underreporting and overreporting of maternal deaths, with possible overreporting predominant. Accurate data is essential for measuring the effectiveness of maternal mortality reduction programs.

Examining interpregnancy intervals and maternal and perinatal health outcomes using U.S. vital records: Important considerations for analysis and interpretation.

BACKGROUND: Numerous studies use birth certificate data to examine the association between interpregnancy interval (IPI) and maternal and perinatal health outcomes. Substantive changes from the latest birth certificate revision have implications for examining this relationship. METHODS: We provide an overview of the National Vital Statistics System and recent changes to the national birth certificate data file, which have implications for assessing IPI and perinatal health outcomes. We describe the calculation of IPI using birth certificate information and related measurement issues. Missing IPI values by maternal age, race and education using 2016 birth certificate data were also compared. Finally, we review and summarise data quality studies of select covariate and outcome variables (sociodemographic, maternal health and health behaviours, and infant health) conducted after the most recent 2003 birth certificate revision. RESULTS: Substantive changes to data collection, dissemination and quality have occurred since the 2003 revision. These changes impact IPI measurement, trends and associations with perinatal health outcomes. Missing values of IPI were highest for older ages, lower education and non-Hispanic black women. Minimal differences were found when comparing IPI using different gestational age measures. Recent data quality studies pointed to substantial variation in data quality by item and across states. CONCLUSION: Future studies examining the association of IPI with maternal and perinatal data using vital records should consider these aspects of the data in their research plan, sensitivity analyses and interpretation of findings.

Trends and state variations in out-of-hospital births in the United States, 2004-2017.

BACKGROUND: Out-of-hospital births have been increasing in the United States, although past studies have found wide variations between states. Our purpose was to examine trends in out-of-hospital births, the risk profile of these births, and state differences in women's access to these births. METHODS: National birth certificate data from 2004 to 2017 were analyzed. Newly available national data on method of payment for the delivery (private insurance, Medicaid, self-pay) were used to measure access to out-of-hospital birth options. RESULTS: After a gradual decline from 1990 to 2004, the number of out-of-hospital births increased from 35 578 in 2004 to 62 228 in 2017. In 2017, 1 of every 62 births in the United States was an out-of-hospital birth (1.61%). Home births increased by 77% from 2004 to 2017, whereas birth center births more than doubled. Out-of-hospital births were more common in the Pacific Northwest and less common in the southeastern states such as Alabama, Louisiana, and Mississippi. Women with planned home and birth center births were less likely to have a number of population characteristics associated with poor pregnancy outcomes, including teen births, smoking during pregnancy, obesity, and preterm, low birthweight, and multiple births. More than 2/3 of planned home births were self-paid, compared with 1/3 of birth center and just 3% of hospital births, with large variations by state. CONCLUSIONS: Lack of insurance or Medicaid coverage is an important limiting factor for women desiring out-of-hospital birth in most states. Recent increases in out-of-hospital births despite important limiting factors highlight the strong motivation of some women to choose out-of-hospital birth.

Trends in Texas maternal mortality by maternal age, race/ethnicity, and cause of death, 2006-2015.

BACKGROUND: Maternal mortality is a sentinel indicator of health care quality. Our purpose was to analyze trends in Texas maternal mortality by demographic characteristics and cause of death, and to evaluate data quality. METHODS: Maternal mortality data were initially analyzed by single years, but then were grouped into 5-year averages (2006-2010 and 2011-2015) for more detailed analyses. Rates were computed per 100 000 live births. A two-proportion z test or Poisson regression for numerators <30 was used to evaluate differences. RESULTS: The Texas maternal mortality rate increased from 18.6 in 2010 to 38.7 in 2012, and then declined nonsignificantly to 32.5 in 2015. The 2011-2015 rate (34.2) was 87% higher than the 2006-2010 rate (18.3). In 2011-2015, the maternal mortality rate for women ≥40 years (558.8) was 27 times higher than for women <40 years (20.7). From 2006-2010 to 2011-2015, the maternal mortality rate increased by 121% for women ≥40 years and by 55% for women <40 years. The rate increased by 132% for nonspecific causes of death, and by 54% for specific causes. Rates for women <40 years for specific causes increased by 36%. CONCLUSIONS: The observed increase in maternal mortality in Texas from 2006-2010 to 2011-2015 is likely a result of both a true increase in rates and increased overreporting of maternal deaths, as indicated by implausibly high and increasing rates for women aged ≥40 years and among nonspecific causes of death. Efforts are needed to strengthen reporting of death certificate data, and to improve access to quality maternal health care services.

Trends in Maternal Mortality by Sociodemographic Characteristics and Cause of Death in 27 States and the District of Columbia.

OBJECTIVE: To analyze recent trends in maternal mortality by sociodemographic characteristics and cause of death and to evaluate data quality. METHODS: This observational study compared data from 2008-2009 with 2013-2014 for 27 states and the District of Columbia that had comparable reporting of maternal mortality throughout the period. Maternal mortality rates were computed per 100,000 live births. Statistical significance of trends and differentials was evaluated using a two-proportion z-test. RESULTS: The study population included 1,687 maternal deaths and 7,369,966 live births. The maternal mortality rate increased by 23% from 20.6 maternal deaths per 100,000 live births in 2008-2009 to 25.4 in 2013-2014. However, most of the increase was among women aged 40 years or older and for nonspecific causes of death. From 2008-2009 to 2013-2014, maternal mortality rates increased by 90% for women 40 years of age or older but did not increase significantly for women younger than 40 years. The maternal mortality rate for nonspecific causes of death increased by 48%; however, the rate for specific causes of death did not increase significantly between 2008-2009 (13.5) and 2013-2014 (15.0). CONCLUSION: Despite the United Nations Millennium Development Goal and a 44% decline in maternal mortality worldwide from 1990 to 2015, maternal mortality has not improved in the United States and appears to be increasing. Maternal mortality rates for women 40 years or older and for nonspecific causes of death were implausibly high and increased rapidly, suggesting possible overreporting of maternal deaths, which may be increasing over time. Efforts to improve reporting for the pregnancy checkbox and to modify coding procedures to place less reliance on the checkbox are essential to improving vital statistics maternal mortality data, the official data source for maternal mortality statistics used to monitor trends, identify at-risk populations, and evaluate the success of prevention efforts.

Explaining the recent decrease in US infant mortality rate, 2007-2013.

BACKGROUND: The US infant mortality rate has been steadily decreasing in recent years as has the preterm birth rate; preterm birth is a major factor associated with death during the first year of life. The degree to which changes in gestational age-specific mortality and changes in the distribution of births by gestational age have contributed to the decrease in the infant mortality rate requires clarification. OBJECTIVE: The objective of the study was to better understand the major contributors to the 2007-2013 infant mortality decline for the total population and for infants born to non-Hispanic black, non-Hispanic white, and Hispanic women. STUDY DESIGN: We identified births and infant deaths from 2007 and 2013 Centers for Disease Control and Prevention National Vital Statistics System's period linked birth and infant death files. We included all deaths and births for which there was a reported gestational age at birth on the birth certificate of 22 weeks or greater. The decrease in the infant mortality rate was disaggregated such that all of the change could be attributed to improvements in gestational age-specific infant mortality rates and changes in the distribution of gestational age, by week of gestation, using the Kitagawa method. Sensitivity analyses were performed to account for records in which the obstetric estimate of gestational age was missing and for deaths and births less than 22 weeks' gestation. Maternal race and ethnicity information was obtained from the birth certificate. RESULTS: The infant mortality rates after exclusions were 5.72 and 4.92 per 1000 live births for 2007 and 2013, respectively, with an absolute difference of -0.80 (14% decrease). Infant mortality rates declined by 11% for non-Hispanic whites, by 19% for non-Hispanic blacks, and by 14% for Hispanics during the period. Compared with 2007, the proportion of births in each gestational age category was lower in 2013 with the exception of 39 weeks during which there was an increase in the proportion of births from 30.1% in 2007 to 37.5% in 2013. Gestational age-specific mortality decreased for each gestational age category between 2007 and 2013 except 33 weeks and >42 weeks. About 31% of the decrease in the US infant mortality rate from 2007 through 2013 was due to changes in the gestational age distribution, and 69% was due to improvements in gestational age-specific survival. Improvements in the gestational age distribution from 2007 through 2013 benefited infants of non-Hispanic white women (48%) the most, followed by infants of non-Hispanic black (31%) and Hispanic (14%) women. CONCLUSION: Infant mortality improved between 2007 and 2013 as a result of both improvements in the distribution of gestational age at birth and improvements in survival after birth. The differential contribution of improvements in the gestational age distribution at birth by race and ethnicity suggests that preconception and antenatal health and health care aimed at preventing or delaying preterm birth may not be reaching all populations.

Recent Increases in the U.S. Maternal Mortality Rate: Disentangling Trends From Measurement Issues.

OBJECTIVE: To develop methods for trend analysis of vital statistics maternal mortality data, taking into account changes in pregnancy question formats over time and between states, and to provide an overview of U.S. maternal mortality trends from 2000 to 2014. METHODS: This observational study analyzed vital statistics maternal mortality data from all U.S. states in relation to the format and year of adoption of the pregnancy question. Correction factors were developed to adjust data from before the standard pregnancy question was adopted to promote accurate trend analysis. Joinpoint regression was used to analyze trends for groups of states with similar pregnancy questions. RESULTS: The estimated maternal mortality rate (per 100,000 live births) for 48 states and Washington, DC (excluding California and Texas, analyzed separately) increased by 26.6%, from 18.8 in 2000 to 23.8 in 2014. California showed a declining trend, whereas Texas had a sudden increase in 2011-2012. Analysis of the measurement change suggests that U.S. rates in the early 2000s were higher than previously reported. CONCLUSION: Despite the United Nations Millennium Development Goal for a 75% reduction in maternal mortality by 2015, the estimated maternal mortality rate for 48 states and Washington, DC, increased from 2000 to 2014; the international trend was in the opposite direction. There is a need to redouble efforts to prevent maternal deaths and improve maternity care for the 4 million U.S. women giving birth each year.

Trends and Characteristics of United States Out-of-Hospital Births 2004-2014: New Information on Risk Status and Access to Care.

BACKGROUND: Out-of-hospital births are increasing in the United States. Our purpose was to examine trends in out-of-hospital births from 2004 to 2014, and to analyze newly available data on risk status and access to care. METHODS: Newly available data from the revised birth certificate for 47 states and Washington, DC, were used to examine out-of-hospital births by characteristics and to compare them with hospital births. Trends from 2004 to 2014 were also examined. RESULTS: Out-of-hospital births increased by 72 percent, from 0.87 percent of United States births in 2004 to 1.50 percent in 2014. Compared with mothers who had hospital births, those with out-of-hospital births had lower prepregnancy obesity (12.5% vs 25.0%) and smoking (2.8% vs 8.5%) rates, and higher college graduation (39.3% vs 30.0%) and breastfeeding initiation (94.3% vs 80.8%) rates. Among planned home births, 67.1 percent were self-paid, compared with 31.9 percent of birth center and 3.4 percent of hospital births. Vaginal births after cesarean (VBACs) comprised 4.6 percent of planned home births and 1.6 percent of hospital and birth center births. Sociodemographic and medical risk status of out-of-hospital births improved substantially from 2004 to 2014. CONCLUSIONS: Improvements in risk status of out-of-hospital births from 2004 to 2014 suggest that appropriate selection of low-risk women is improving. High rates of self-pay for the costs of out-of-hospital birth suggest serious gaps in insurance coverage, whereas higher-than-average rates of VBAC could reflect lack of access to hospital VBACs. Mandating private insurance and Medicaid coverage could substantially improve access to out-of-hospital births. Improving access to hospital VBACs might reduce the number of out-of-hospital VBACs.

Trends in Stillbirth by Gestational Age in the United States, 2006-2012.

OBJECTIVE: To evaluate stillbirth trends by gestational age. METHODS: National Center for Health Statistics' fetal death and live birth data files were used to analyze the 2006 and 2012 cohorts of deliveries and compute gestational age-specific stillbirth rates at 20 weeks of gestation or greater using two methods: traditional (eg, stillbirths at 38 weeks of gestation/live births and stillbirths at 38 weeks of gestation) and prospective (stillbirths at 38 weeks of gestation/number of women still pregnant at 38 weeks of gestation). Changes in rates and in the percent distribution of stillbirths and live births were assessed. RESULTS: In 2006 and 2012, the stillbirth rate was 6.05 stillbirths per 1,000 deliveries. There was little change in the percent distribution of stillbirths by gestational age from 2006 to 2012. However, the percent distribution of live births by gestational age changed considerably: births at 34-38 weeks of gestation decreased by 10-16%, and births at 39 weeks of gestation increased by 17%. Traditionally computed stillbirth rates were unchanged at most gestational ages, but rose at 24-27, 34-36, 37, and 38 weeks of gestation. However, rates were influenced by decreases in births at those gestational ages; the pattern of stillbirths by gestational age was unchanged. In contrast, there were no differences in prospective stillbirth rates at 21-42 weeks of gestation. CONCLUSION: The lack of change in prospective stillbirth rates from 2006 to 2012 suggests that preventing nonmedically indicated deliveries before 39 weeks of gestation did not increase the U.S. stillbirth rate. LEVEL OF EVIDENCE: II.

Infant Mortality Statistics From the 2013 Period Linked Birth/Infant Death Data Set.

OBJECTIVES: This report presents 2013 period infant mortality statistics from the linked birth/infant death data set (linked file) by maternal and infant characteristics. The linked file differs from the mortality file, which is based entirely on death certificate data. METHODS: Descriptive tabulations of data are presented and interpreted. RESULTS: The U.S. infant mortality rate was 5.96 infant deaths per 1,000 live births in 2013, similar to the rate of 5.98 in 2012. The number of infant deaths was 23,446 in 2013, a decline of 208 infant deaths from 2012. From 2012 to 2013, infant mortality rates were stable for most race and Hispanic origin groups; declines were reported for two Hispanic subgroups: Cuban and Puerto Rican. Since 2005, the most recent high, the U.S. infant mortality rate has declined 13% (from 6.86), with declines in both neonatal and postneonatal mortality overall and for most groups. In 2013, infants born at 37­38 weeks of gestation (early term) had mortality rates that were 63% higher than for full-term (39­40 week) infants. For multiple births, the infant mortality rate was 25.84, 5 times the rate of 5.25 for singleton births. In 2013, 36% of infant deaths were due to preterm-related causes of death, and an additional 15% were due to causes grouped into the sudden unexpected infant death category.