Adverse maternal, fetal, and newborn outcomes among pregnant women with SARS-CoV-2 infection: an individual participant data meta-analysis.

Introduction: Despite a growing body of research on the risks of SARS-CoV-2 infection during pregnancy, there is continued controversy given heterogeneity in the quality and design of published studies.

Methods: We screened ongoing studies in our sequential, prospective meta-analysis. We pooled individual participant data to estimate the absolute and relative risk (RR) of adverse outcomes among pregnant women with SARS-CoV-2 infection, compared with confirmed negative pregnancies. We evaluated the risk of bias using a modified Newcastle-Ottawa Scale.

Results: We screened 137 studies and included 12 studies in 12 countries involving 13 136 pregnant women.Pregnant women with SARS-CoV-2 infection-as compared with uninfected pregnant women-were at significantly increased risk of maternal mortality (10 studies; n=1490; RR 7.68, 95% CI 1.70 to 34.61); admission to intensive care unit (8 studies; n=6660; RR 3.81, 95% CI 2.03 to 7.17); receiving mechanical ventilation (7 studies; n=4887; RR 15.23, 95% CI 4.32 to 53.71); receiving any critical care (7 studies; n=4735; RR 5.48, 95% CI 2.57 to 11.72); and being diagnosed with pneumonia (6 studies; n=4573; RR 23.46, 95% CI 3.03 to 181.39) and thromboembolic disease (8 studies; n=5146; RR 5.50, 95% CI 1.12 to 27.12).Neonates born to women with SARS-CoV-2 infection were more likely to be admitted to a neonatal care unit after birth (7 studies; n=7637; RR 1.86, 95% CI 1.12 to 3.08); be born preterm (7 studies; n=6233; RR 1.71, 95% CI 1.28 to 2.29) or moderately preterm (7 studies; n=6071; RR 2.92, 95% CI 1.88 to 4.54); and to be born low birth weight (12 studies; n=11 930; RR 1.19, 95% CI 1.02 to 1.40). Infection was not linked to stillbirth. Studies were generally at low or moderate risk of bias.

Conclusions: This analysis indicates that SARS-CoV-2 infection at any time during pregnancy increases the risk of maternal death, severe maternal morbidities and neonatal morbidity, but not stillbirth or intrauterine growth restriction. As more data become available, we will update these findings per the published protocol.

Competing Interests: Competing interests: CW declares a relationship with Ferring Pharmaceuticals COVID-19 Investigational Grant and NHMRC Fellowship (salary support). AP declares the following research grants to her institution: ‘H2020-Grant—Consortium member of Innovative medicine initiative call 13 topic 9 «ConcePTION», Efficacy and safety studies on Medicines EMA/2017/09/PE/11, Lot 4, WP 2 lead, Safety monitoring of COVID-19 vaccines in the EU—Reopening of competition no. 20 under a framework contract following procurement procedure EMA/2017/09/PE (Lot 3) (Euro 110,000), Federal Office of Public Health (207,000 CHF)’. EM declares a relationship with the National Institute for Health Research (project grant for PAN COVID study). DM declares a relationship with the Canadian Institutes of Health Research (payments to institution only), Public Health Agency of Canada (payments to institution only), BC Women’s Foundation (payments to institution only) and is a member of the COVID-19 Immunity Task Force sponsored by the Canadian government. TDM declares a relationship with Pfizer (site principal investigator for SARS-CoV-2 vaccination in pregnancy study, money paid to institution and member of Medical Advisory Board for SARS-CoV-2 vaccination in pregnancy study, money paid to TDM), NICHD (subcommittee chair for the NICHD Maternal-Fetal Medicine Units Network Gestational Research Assessments of COVID-19 (GRAVID) study) and Society for Maternal-Fetal Medicine (board member). EL declares a relationship with the US NIH (paid institution) and is an employee of AbbVie, but was employed at the University of Washington at the time of the study. KK declares a relationship with the Bill & Melinda Gates Foundation. VJF declares a relationship with the Bill & Melinda Gates Foundation (payments to institution), Yellow Chair Foundation (payments to institution), Robert Woods Johnson Foundation (payments to institution), CDC Foundation, California Health Care Foundation (payments to institution), Tara Health Foundation (payments to institution), UCSF Women’s Health Center of Excellence (payments to institution) and California Department of Health Care Services (payments made to institution). JS-B declares a relationship with the Ferring Pharmaceuticals, which gave a grant ($10 000) for the expenses of RECOGEST trial and is a part of the Columbian Federation of Perinatology. YA declares a relationship with the Bill & Melinda Gates Foundation (payments made to institution), CDC Foundation (payments made to institution), Robert Woods Johnson Foundation (payments made to institution) and UCLA Dean’s Office COVID-19 research (payments made to institution). RC declares a relationship with the NIH HD36801 (MFMU Network DCC). MCN declares a relationship with the BMGF (project grant made to institution), EDCTP, Sanofi, AstraZeneca, Pfizer (research grants made to institution), Sanofi Pasteur (payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events) and Sanofi Pasteur and Pfizer (payment for expert testimony). ESM declares a relationship with Pfizer (site principal investigator for phase 2/3 RCT of COVID vaccine during pregnancy). OS declares a relationship with the NordForsk Funding (Nordic research funding grant number: 105545), the Swedish Medical Products Agency (funding for reports on COVID-19 vaccines and pregnancy) and Karolinska Institutet (funding for COVID research and pregnancy: 2020-01567). EG declares a relationship with the Stavros Niarchos Foundation, Santander Foundation and ‘La Caixa’ Foundation (payments made to institution). SAM declares a relationship with BMGF (funded study in South Africa).

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