Perinatal outcomes after admission with COVID-19 in pregnancy: a UK national cohort study

Abstract

There are few population-based studies of sufficient size and follow-up duration to have reliably assessed perinatal outcomes for pregnant women hospitalised with SARS-CoV-2 infection. The United Kingdom Obstetric Surveillance System (UKOSS) covers all 194 consultant-led UK maternity units and included all pregnant women admitted to hospital with an ongoing SARS-CoV-2 infection. Here we show that in this large national cohort comprising two years' active surveillance over four SARS-CoV-2 variant periods and with near complete follow-up of pregnancy outcomes for 16,627 included women, severe perinatal outcomes were more common in women with moderate to severe COVID-19, during the delta dominant period and among unvaccinated women. We provide strong evidence to recommend continuous surveillance of pregnancy outcomes in future pandemics and to continue to recommend SARS-CoV-2 vaccination in pregnancy to protect both mothers and babies.

Fig. 1. Monthly cumulative incidence (%) of perinatal outcomes.

Stillbirth, preterm birth (<34 weeks’ and 34⁺⁰ –36⁺⁶  weeks) and admission to a neonatal unit is shown by symptom status with asymptomatic women in the upper panel and symptomatic women in the lower panel. Number of women admitted to hospital for each month from March 2020 to March 2022 is shown on Y axis to the right. Vaccination status among included women by minimum number of doses recorded; at least 1 dose, 2 doses or 3 doses (%) is shown in the dotted lines. The vertical dashed lines indicate key vaccination policies: The first COVID-19 vaccine in pregnancy was administered in the U.K. in December 31, 2020, and pregnant women were included as priority group by the Joint Committee on Vaccination and Immunisation (JCVI) in the U.K in December 2021. The dominant SARS-CoV-2 variant is indicated by the background colour; wild-type, alpha, delta and omicron.