ABSTRACT
OBJECTIVE: The COVID pandemic has been associated with varied effects on preterm birth (PTB). We sought to compare rates of PTB during the pre- and post vaccination COVID periods with pre-pandemic PTB rates, stratified by race and ethnicity. STUDY DESIGN: Retrospective cohort comparing all deliveries over 20 weeks at a single tertiary center during "early" (March 2020-June 2020) versus "late" COVID (March 2021-June 2021), and "late" COVID versus pre-COVID (March to June 2014-2019). PTBs <37, <34, and <28 weeks were compared and stratified by race/ethnicity. RESULTS: A total of 16,483 deliveries occurred including 2,068 "early" COVID, 2,115 "late" COVID, and 12,300 pre-COVID. The PTB rate during "late" COVID was lower compared to "early" COVID (12.1 vs. 14.6%, p = 0.02). Rate of PTB <34 was also lower during "late" COVID (4.4 vs. 5.7%, p = 0.05). PTB <28 did not differ. When controlling for prior PTB, "late" COVID remained associated with a decreased risk of PTB compared to "early" COVID, adjusted odds ratio (aOR) of 0.82 (95% confidence interval [CI]: 0.68, 0.98). Although there was no difference in PTB among Hispanic individuals when comparing "late" COVID versus pre-COVID, when further subdivided, a small number of Hispanic Puerto Rican individuals had higher odds of PTB < 37 during "late" COVID versus pre-COVID (aOR = 4.29 [95% CI: 1.12, 16.4]). Additionally, White individuals had reduced odds of PTB <37 (aOR = 0.80 [95% CI: 0.65, 0.98]) during "late" COVID versus pre-COVID while the PTB rate was unchanged when comparing "late" COVID versus pre-COVID in all other racial and ethnic groups. CONCLUSION: During 2021, PTB rates decreased from rates observed in 2020 at the height of COVID restrictions. Among White birthing individuals, PTB decreased in 2021 compared to pre-COVID rates. This decrease was not observed in Black and Hispanic birthing individuals. These data highlight the continued racially disparate impact of the COVID-19 pandemic on PTB rates. KEY POINTS: · The COVID-19 pandemic has been associated with varied effects on the preterm birth (PTB) rate.. · PTB rates decreased in "late" COVID compared to "early" COVID.. · When stratified, PTB decreased among white individuals, but not in Black or Hispanic individuals..