The impact of COVID-19 on pregnancy outcomes in a diverse cohort in England

There is conflicting evidence regarding the effect of coronavirus disease (COVID-19) in pregnancy. Risk factors for COVID-19 overlap with risk factors for pregnancy complications. We aimed to assess the effects of the COVID-19 pandemic and confirmed SARS-CoV-2 infection on pregnancy outcomes. A retrospective interrupted time-series and matched cohort analysis was performed. Singleton pregnancies completed between 1st January 2016 and 31st January 2021 were included. Trends in outcomes were analysed over time. Modelled COVID-19 transmission data were applied to deliveries since 1st January 2020 to assign a risk of COVID-19 to each pregnancy, and incorporated into a regression model of birthweight. Confirmed COVID-19 cases were matched to controls delivered in the pre-pandemic period, and maternal and neonatal outcomes compared. 43,802 pregnancies were included, with 8343 in the model of birthweight. There was no increase in the risk of stillbirth (p = 0.26) or neonatal death (p = 0.64) during the pandemic. There was no association between modelled COVID-19 attack rate (%) in any trimester and birthweight (first trimester p = 0.50, second p = 0.15, third p = 0.16). 214 COVID-positive women were matched to controls. Preterm birth was more common in symptomatic cases (14/62, 22.6%) compared to asymptomatic cases (9/109, 8.3%, p = 0.008) and controls (5/62, 8.1%, p = 0.025). Iatrogenic preterm birth was more common in cases (21/214, 9.8%) than controls (9/214, 4.2%, p = 0.02). All other examined outcomes were similar between groups. There was no significant impact of COVID-19 on the examined birth outcomes available. Symptomatic COVID-19 should be considered a risk factor for preterm birth, possibly due to an increase in iatrogenic deliveries for maternal indications.