Severity of maternal SARS-CoV-2 infection and perinatal outcomes of women admitted to hospital during the omicron variant dominant period using UK Obstetric Surveillance System data: prospective, national cohort study

Hilde M Engjom; Rema Ramakrishnan; Nicola Vousden; Kathryn Bunch; Eddie Morris; Nigel A B Simpson; Chris Gale; Patrick O'Brien; Maria Quigley; Peter Brocklehurst; Jennifer J Kurinczuk; Marian Knight

doi:10.1136/bmjmed-2022-000190

Severity of maternal SARS-CoV-2 infection and perinatal outcomes of women admitted to hospital during the omicron variant dominant period using UK Obstetric Surveillance System data: prospective, national cohort study

BMJ Med. 2022 Aug 24;1(1):e000190. doi: 10.1136/bmjmed-2022-000190. eCollection 2022.

Authors

Hilde M Engjom^#^{1

2}, Rema Ramakrishnan^#², Nicola Vousden², Kathryn Bunch², Eddie Morris^{3

4}, Nigel A B Simpson⁵, Chris Gale⁶, Patrick O'Brien^{4

7}, Maria Quigley², Peter Brocklehurst⁸, Jennifer J Kurinczuk², Marian Knight²

Affiliations

¹ Division of Mental and Physical Health, Norwegian Institute of Public Health, Bergen, Bergen, Norway.
² National Perinatal Epidemiology Unit, University of Oxford, Oxford, Oxfordshire, UK.
³ Department of Obstetrics and Gynaecology, Norfolk and Norwich University Hospital NHS Trust, Norwich, Norfolk, UK.
⁴ Royal College of Obstetricians and Gynaecologists, London, London, UK.
⁵ Department of Women's & Children's Health, University of Leeds, Leeds, West Yorkshire, UK.
⁶ Neonatal Medicine, School of Public Health, Faculty of Medicine, Imperial College London, London, UK.
⁷ Institute for Women's Health, University College London, London, UK.
⁸ Birmingham Clinical Trials Unit, University of Birmingham, Birmingham, West Midlands, UK.

^# Contributed equally.

Abstract

Objectives: To describe the severity of maternal infection when the omicron SARS-CoV-2 variant (B.1.1.529) was dominant (15 December 2021 to 14 March 2022) and describe outcomes by symptoms and vaccination status.

Design: Prospective, national cohort study using the UK Obstetric Surveillance System.

Setting: 94 hospitals in the UK with a consultant led maternity unit.

Participants: Pregnant women admitted to hospital for any cause with a positive SARS-CoV-2 test.

Main outcome measures: Symptomatic or asymptomatic infection, vaccination status by doses before admission, and severity of maternal infection (moderate or severe infection according to modified World Health Organization's criteria).

Results: Of 3699 women who were admitted to hospital, 986 (26.7%, 95% confidence interval 25.3% to 28.1%) had symptoms; of these, 144 (14.6%, 12.5% to 17.0%) had a moderate to severe infection, 99 (10.4%, 8.6% to 12.5%) of 953 received respiratory support, and 30 (3.0%, 2.1% to 4.3%) were admitted to an intensive care unit. Covid-19 specific drug treatment was given to 13 (43.3%) of the 30 women in intensive care. Four women with symptoms died (0.4%, 0.1% to 1.1%). Vaccination status was known for 845 (85.6%) women with symptoms; 489 (58.9%) were unvaccinated and only 55 (6.5%) had three doses. Moderate to severe infection was reported for 93 (19.0%) of 489 unvaccinated women with symptoms, decreasing to three (5.5%) of 55 after three doses. Among the 30 women with symptoms who were admitted to intensive care, 23 (76.7%) were unvaccinated and none had received three doses.

Conclusion: Most women with severe covid-19 disease were unvaccinated and vaccine coverage among pregnant women admitted to hospital with SARS-CoV-2 was low. Ongoing action to prioritise and advocate for vaccine uptake in pregnancy is essential. A better understanding of the persistent low use of drug treatments is an urgent priority.

Trial registration: ISRCTN 40092247.

Keywords: COVID-19; Infectious disease medicine; Obstetrics; Pregnancy complications; Public health.