Seroprevalence and presentation of SARS-CoV-2 in pregnancy
Authors: Francesca Crovetto, Fàtima Crispi, Elisa Llurba, Francesc Figueras, María Dolores Gómez-Roig, Eduard Gratacós
Journal: The Lancet (2020)

One of several case series of pregnant women diagnosed with COVID-19 by PCR reports that 41 (10%) of the 427 women required admission to a critical care unit.1Knight M Bunch K Vousden N et al.Characteristics and outcomes of pregnant women admitted to hospital with confirmed SARS-CoV-2 infection in UK: national population based cohort study.BMJ. 2020; 369m2107Crossref PubMed Scopus (730) Google Scholar Most women described in these case series are in the third trimester of pregnancy, which could reflect reporting bias, or a higher risk of infection or increased disease severity compared with women in the first trimester of pregnancy.2Rasmussen SA Jamieson DJ Bresee JS Pandemic influenza and pregnant women.Emerg Infect Dis. 2008; 14: 95-100Crossref PubMed Scopus (286) Google Scholar Seroprevalence studies can detect infections that test negative on PCR, and provide information on early pregnancy, when doing PCR in asymptomatic individuals is logistically difficult. We tested for antibodies for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in 874 pregnant women consecutively attending first trimester screening (ie, at 10–16 weeks of gestation; n=372) or delivery (n=502) from April 14 to May 5, 2020, at three university hospitals (ie, Hospital Sant Joan de Déu, Hospital Clínic, and Sant Pau) in Barcelona, Spain. At enrolment, women were interviewed for COVID-19 symptoms during the previous 2 months. We tested for anti-SARS-CoV-2 IgG, IgM, and IgA antibodies in participants' serum using VIRCLIA (Vircell Microbiologist, Granada, Spain). We re-tested 107 indeterminate results using VITROS (Ortho Clinical Diagnostics, Rochester, NY, USA) and re-classified samples as positive or negative for these antibodies. Women with COVID-19 were treated according to a standard protocol.3López M Gonce A Meler E et al.Coronavirus disease 2019 in pregnancy: a clinical management protocol and considerations for practice.Fetal Diagn Ther. 2020; 47: 519-528Crossref PubMed Scopus (53) Google Scholar 125 (14%) of the 874 women were positive for anti-SARS-CoV-2 IgG, IgM, or IgA; 54 (15%) of the 372 women in the first trimester of pregnancy and 71 (14%) of the 502 women in the third trimester. 75 (60%) of the 125 women who were seropositive reported having no previous symptoms and 50 (40%) reported one symptom or more. 31 women (25%) had at least three symptoms or anosmia and eight (6%) had dyspnoea. Seven women (6%) were admitted to hospital for persistent fever (>38°C) and dyspnoea. Of these seven women, three had pneumonia that was classified as severe (bilateral chest condensation, respiratory rate >30 breaths per min, and leucopenia), required oxygen support but not critical care, and were discharged well. Symptomatic infection, hospital admission, and dyspnoea were significantly more prevalent in women in the third trimester of pregnancy than in women in the first trimester of pregnancy (appendix pp 1–2). We have found a substantially higher seroprevalence (14%) of SARS-CoV-2 than that found by use of the SARS-CoV-2 PCR-positive rates (0·78%) in women aged 20–40 years in Barcelona, Spain.4Generalitat de CatalunyaInteractive case map by municipality.http://aquas.gencat.cat/ca/actualitat/ultimes-dades-coronavirus/mapa-per-municipis/index.html#googtrans(ca|en)Date accessed: June 12, 2020Google Scholar Our data suggest that COVID-19 is commonly asymptomatic in pregnant women5Breslin N Baptiste C Gyamfi-Bannerman C et al.Coronavirus disease 2019 infection among asymptomatic and symptomatic pregnant women: two weeks of confirmed presentations to an affiliated pair of New York City hospitals.Am J Obstet Gynecol MFM. 2020; 2100118Summary Full Text Full Text PDF PubMed Scopus (577) Google Scholar and illustrate that seroprevalence studies might capture undiagnosed infections and offer different estimates of infection severity. In this study, none of the 125 women who were infected with SARS-CoV-2 required critical care, compared with the 10% of women diagnosed with COVID-19 by PCR.1Knight M Bunch K Vousden N et al.Characteristics and outcomes of pregnant women admitted to hospital with confirmed SARS-CoV-2 infection in UK: national population based cohort study.BMJ. 2020; 369m2107Crossref PubMed Scopus (730) Google Scholar We believe these data are reassuring and relevant to pregnant women and obstetricians. Seroprevalence was similar between women in the first trimester of pregnancy and women in the third trimester, suggesting a similar risk of infection, but the proportion of women with symptoms and the proportion of women who required hospitalisation were higher in the third trimester group than in the first trimester group. This result agrees with data reported from case registries of pregnant women with COVID-19,1Knight M Bunch K Vousden N et al.Characteristics and outcomes of pregnant women admitted to hospital with confirmed SARS-CoV-2 infection in UK: national population based cohort study.BMJ. 2020; 369m2107Crossref PubMed Scopus (730) Google Scholar suggesting that, as with other respiratory viruses, SARS-CoV-2 might cause more severe disease and require increased surveillance in late pregnancy than in early pregnancy. These findings should be further investigated in larger studies. Samples of serum and peripheral blood mononuclear cells obtained in this study are stored at biobanks for future studies with better or complementary immunological tests. Long-term follow-up of the infants is now underway given the fact that SARS-CoV-2 is potentially neurotropic.6Vivanti AJ Vauloup-Fellous C Prevot S et al.Transplacental transmission of SARS-CoV-2 infection.Nat Commun. 2020; 113572Crossref PubMed Scopus (18) Google Scholar This online publication has been corrected. The corrected version first appeared at thelancet.com on October 22, 2020 This online publication has been corrected. The corrected version first appeared at thelancet.com on October 22, 2020 We declare no competing interests. This study was funded by the Kids Corona Child and Mother COVID-19 Open Data and Biobank Initiative, Hospital Sant Joan de Déu, Barcelona, Spain, the LaCaixa Foundation, Barcelona, Spain, the Stavros Niarchos Foundation, Banco Santander, and other private donors of Kids Corona. We thank all the medical staff, junior doctors, midwives, and nurses of BCNatal (Hospitals Sant Joan de Déu and Clínic) and Hospital Sant Pau. We especially thank Rosalia Pascal, Marta Larroya, Cristina Trilla, Martí Cantallops, Marta Camacho, M Carmen Medina, Irene Casas, Marta Tortajada, Alex Cahuana, Patricia Muro, Marta Valdés-Bango, David Boada, and Anna Mundo for data collection; Angela Arranz for her role in the coordination of the nursing research team; Imma Mercade, Elena Casals, and Josefina Mora for their contribution to the collection of first trimester samples; Jordi Yague and M Angeles Marcos for supervising the antibodies analyses; and the biobanks of Fundació Sant Joan de Déu, Clínic-IDIBAPS, and Sant Pau in Barcelona, Spain, for management of the samples. Download .pdf (.3 MB) Help with pdf files Supplementary appendix Department of ErrorCrovetto F, Crispi F, Llurba E, Figueras F, Gómez-Roig MD, Gratacós E. Seroprevalence and presentation of SARS-CoV-2 in pregnancy. Lancet 2020; 396: 530–31—In this Correspondence, the Stavros Niarchos Foundation, Banco Santander, and other private donors of Kids Corona should have been acknowledged as funders. This correction has been made to the online version as of Oct 22, 2020. Full-Text PDF