VP31.05: Pregnancy outcomes during the COVID‐19 pandemic: a population‐level analysis

Abstract

There is conflicting international evidence regarding the effect of COVID-19 in pregnancy. We aimed to assess the effects of the COVID-19 pandemic on pregnancy outcomes. Retrospective population-level analysis using routinely collected clinical data at a large tertiary maternity unit in England. Singleton pregnancies completed beyond 16 weeks of gestation between 1 January 2016 and 31 January 2021 were included. Trends in birth weight, preterm birth, Caesarean section rate and perinatal mortality were analysed over time. Modelled COVID-19 transmission data were applied to deliveries since 1 January 2020 to assign an individual risk of COVID-19 to each pregnancy, expressed as attack rate. This was incorporated into a regression model of birth weight to account for under-ascertainment of COVID-19 cases. Asymptomatic n = 77 Mild n = 195 Moderate/Severe n = 29 43,802 pregnancies were included, with 8,343 since 1 January 2020 included in the model of birth weight. The risk of Caesarean section increased during the pandemic period (OR 1.11, 95% CI 1.03 to 1.19, p = 0.006). There was no change in the risk of stillbirth (OR 0.78, 95% CI 0.51 to 1.20, p = 0.26) or neonatal death (OR 0.89, 95% CI 0.54 to 1.47, p = 0.64). Accounting for other determinants of fetal growth there was no association between modelled COVID-19 attack rate (%) in any trimester and birth weight (first trimester p = 0.50, second p = 0.15, third p = 0.16). There was a trend towards an increase in birth weight z-score during the pandemic (Mean difference 0.04, 95% CI 0.00-0.07, p = 0.054). There was no significant change in the risk of preterm birth (OR 1.00, 95% CI 0.91-1.10, p = 0.93). We found no evidence of an overall effect of the COVID-19 pandemic on perinatal mortality or preterm birth, and in contrast to other reports there may a small increase in mean birth weight associated with the pandemic and lockdown periods. An increase in Caesarean section rate may represent a lower threshold for obstetric intervention due to COVID-19.