Global maternal mortality associated with SARS-CoV-2 infection: a systematic review and meta-analysis

Abstract

Background: Pregnant and recently pregnant women infected with SARS-CoV-2 are at increased risk of death and serious complications than those without the infection. The extent of variation in mortality rates in pregnant women with SARS-CoV-2 infection across regions, and the causes of death are not known. We systematically reviewed all available evidence on the variation in mortality rates in pregnant women with SARS-CoV-2 infection across geographical and country income groups, and the reported cause of death.

Methods: We searched major databases (December 2019-January 2023) including Medline, LILACS, BIREME and Embase. We included studies that reported deaths in at least 10 consecutive pregnant or recently pregnant women with confirmed SARS-CoV-2 infection and assessed the studies' risk of bias. We calculated the summary estimates of any cause of death as proportions with 95% CIs using a multilevel random-effects logistic regression model. Subgroup analyses were performed by geographical region and country income groups. We used International Statistical Classification of Diseases and Related Health Problems-Maternal Mortality to categorise the reported cause of death.

Findings: From 1 326 315 citations, we included 169 studies (319 172 women with confirmed SARS-CoV-2 infection; 4253 women died). The overall rate of unspecified maternal death was 0.87% (95% CI 0.64% to 1.16%). There were significant differences between geographical regions in rates of maternal mortality, with the highest rates in Sub-Saharan Africa (3.48%; 95% CI 0.66% to 16.42%) and Latin America and the Caribbean (3.16%, 95% CI 1.53% to 6.43%). Rates of maternal mortality varied by country income groups, with the highest rates in low-income countries (4.66%, 95% CI 0.75% to 24.07%). Among women with reported cause of death, 98.6% (2,390/2,423) of deaths were attributable to COVID-19.

Interpretation: Rates of deaths in pregnant and recently pregnant women with SARS-CoV-2 infection vary significantly across regions and by country income groups, with the highest burden in Sub-Saharan Africa and low-income countries. COVID-19 is the main reported cause of death.

Prospero registration number: CRD42020224120.

Keywords: Maternal health; SARS.

Figure 1. Study selection process in the systematic review: *Twitter, national reports, blog Thornton J, ObG Project, COVID-19 & Pregnancy Cases, https://www.obgproject.com/2020/04/07/covid-19-research-watch-with-dr-jim-thornton/; EPPI-Centre, COVID-19: a living systematic map of evidence, http://eppi.ioe.ac.uk/cms/Projects/DepartmentofHealthandSocialCare/Publishedreviews/COVID19Livingsystematicmapoftheevidence/tabid/3765/Default.aspx; Norwegian Institute of Public Health, NIPH systematic and living map on COVID-19 evidence, https://www.nornesk.no/forskningskart/NIPH_mainMap.html; John Hopkins University Center for Humanitarian Health; COVID-19, Maternal and Child Health, Nutrition, http://hopkinshumanitarianhealth.org/empower/advocacy/covid-19/covid-19-children-and-nutrition/; ResearchGate, COVID-19 research community, https://www.researchgate.net/community/COVID-19; Living Overview of the Evidence, Coronavirus disease (COVID-19), https://app.iloveevidence.com/loves/5e6fdb9669c00e4ac072701d?population=5d062d5fc80dd41e58ba8459.

Figure 2. Risk of bias.