Exploring the Decline in the Singleton Preterm Birth Rate in the United States, 2019–2020

This report is limited to singleton births and describes trends in preterm birth rates from 2014 through 2020 and changes in rates between 2019 and 2020 by maternal race and Hispanic origin, age, and state of residence.

Fetal Mortality in the United States: Trends From 2014 Through 2019 and Changes Between 2018–2019 and 2019–2020

This report describes 2014–2019 trends and changes from 2019 to 2020 for total, early, and late fetal mortality, and compares changes by maternal race and Hispanic origin and by state between 2018–2019 and 2019–2020.

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

This report presents data on distributions in prepregnancy body mass index, including the three classes of obesity, by maternal race and Hispanic origin for women who gave birth in 2020.

Racial and Ethnic Disparities in Cesarean Morbidity

Background Maternal race and ethnicity have been identified as significant independent predictors of obstetric morbidity and mortality in the United States. An appreciation of the clinical contexts in which maternal racial and ethnic disparities are most pronounced can better target efforts to alleviate these disparities and improve outcomes. It remains unknown whether cesarean delivery precipitates these divergent outcomes. Objective This study assessed the association between maternal race and ethnicity and cesarean complications. Study Design We conducted a retrospective cohort study from a multicenter observational cohort of women undergoing cesarean delivery. Nulliparous women with non-anomalous singleton gestations who underwent primary cesarean section were included. Race/ethnicity was categorized as non-Hispanic White, non-Hispanic Black, Hispanic, Asian, Native American, or unknown. The primary outcome was a composite of maternal cesarean complications including hysterectomy, uterine atony, blood transfusion, surgical injury, arterial ligation, infection, wound complication, and ileus. A composite of neonatal morbidity was evaluated as a secondary outcome. We created a multivariable logistic regression model adjusting for selected demographic and obstetric variables that may influence the likelihood of the primary outcome. Results A total of 14,570 women in the parent trial met inclusion criteria with an 18.8% incidence of the primary outcome (2,742 women). After adjusting for potential confounding variables, maternal surgical morbidity was found to be significantly higher for non-Hispanic Black (adjusted odds ratios [aORs] 1.96, 95% confidence intervals [CIs] 1.63–2.35) and Hispanic (aOR 1.66, 95% CI 1.37–2.01) women as compared with non-Hispanic white women. Neonatal morbidity was similarly found to be significantly associated with the Black race and Hispanic ethnicity. Conclusion In this cohort, the odds of cesarean-related maternal and neonatal morbidity were significantly higher for non-Hispanic Black and Hispanic women. These findings suggest race as a distinct risk factor for cesarean complications, and efforts to alleviate disparities should highlight cesarean section as an opportunity for improvement in outcomes. Key Points

Association between early gestation passive smoke exposure and neonatal size among self-reported non-smoking women by race/ethnicity: A cohort study

Understanding implications of passive smoke exposure during pregnancy is an important public health issue under the Developmental Origins of Health and Disease paradigm. In a prospective cohort of low-risk non-smoking pregnant women (NICHD Fetal Growth Studies—Singletons, 2009–2013, N = 2055), the association between first trimester passive smoke exposure and neonatal size was assessed by race/ethnicity. Plasma biomarker concentrations (cotinine, nicotine) assessed passive smoke exposure. Neonatal anthropometric measures included weight, 8 non-skeletal, and 2 skeletal measures. Linear regression evaluated associations between continuous biomarker concentrations and neonatal anthropometric measures by race/ethnicity. Cotinine concentrations were low and the percent above limit of quantification varied by maternal race/ethnicity (10% Whites; 14% Asians; 15% Hispanics; 49% Blacks). The association between cotinine concentration and infant weight differed by race/ethnicity (Pinteraction = 0.034); compared to women of the same race/ethnicity, per 1 log-unit increase in cotinine, weight increased 48g (95%CI -44, 139) in White and 51g (95%CI -81, 183) in Hispanic women, but decreased -90g (95%CI -490, 309) in Asian and -93g (95%CI -151, -35) in Black women. Consistent racial/ethnic differences and patterns were found for associations between biomarker concentrations and multiple non-skeletal measures for White and Black women (Pinteraction<0.1). Among Black women, an inverse association between cotinine concentration and head circumference was observed (−0.20g; 95%CI −0.38, −0.02). Associations between plasma cotinine concentration and neonatal size differed by maternal race/ethnicity, with increasing concentrations associated with decreasing infant size among Black women, who had the greatest biomarker concentrations. Public health campaigns should advocate for reducing pregnancy exposure, particularly for vulnerable populations.

Fetal Mortality: United States, 2019

This report presents 2019 fetal mortality data by maternal race and Hispanic origin, age, tobacco use during pregnancy, and state of residence, as well as by plurality, sex, gestational age, birthweight, and selected causes of death. Trends in fetal mortality are also examined.