U.S. preterm birth rates reduced nationwide, particularly among medically-induced deliveries, during the COVID-19 pandemic lockdown period

Background During the early months of the COVID-19 pandemic, many studies—particularly from wealthy nations—reported a drop in preterm birth rates. Our goal was to examine nationwide changes in U.S. preterm births in relation to a range of sociodemographic, perinatal conditions, and obstetric care factors. Methods Using data from the publicly available natality files from the National Center for Health Statistics, we examined 25,767,850 observations of all U.S. registered singleton births during the months of April to June (i.e. early pandemic lockdown months) for the years 2015 to 2021. To control for seasonal shifts and focus on the early onset of the pandemic, we calculated average annual preterm birth rates (< 37 weeks gestation) between the months of April to June. We used these observed rates to generate predicted rates for 2020 and 2021, and stratified by sociodemographic and medical characteristics of interest. Results The nationwide preterm birth rate has been increasing since 2015, but this trend was temporarily interrupted by a significant decrease in the early months of the pandemic. Preterm birth rates dropped for nearly everyone regardless of their sociodemographic characteristics. Additionally, there was a significant and steeper drop for late compared to early preterm births, for preterm home births compared to preterm hospital births, and significantly lower rates of preterm birth among those with induced births (c-section or vaginal). The average number of prenatal visits decreased in these months, and preterm birth rates significantly decreased among those with low (0–10) and average (11–15) number of prenatal visits. The decrease in preterm birth rates during this period was also accompanied by a decrease in fetal death rates, and decreases in neonatal and maternal intensive care admissions. Conclusion Our analyses indicate a potentially unintended interim health benefit of the pandemic across nearly all sociodemographic groups, with significant decreases particularly among induced preterm births. These findings, paired with reduced rates of fetal deaths and maternal and neonatal ICU admissions, suggest that in some cases, less intervention may have served as a benefit to reproductive outcomes. These results support the reduction in prenatal visits recommended by the 2025 national obstetric guidelines.