We still have a long ways to go before fully understanding the potential effects of Covid-19 on pregnant women and their infants but based on data to date the disease severity seems similar to that of non-pregnant people and vertical transmission seems rare.
In one of the larger studies involving 158 obstetric patients with Covid-19 from New York City, ~80% had mild or asymptomatic disease with the rest manifesting moderate or severe disease (1). Cough and fever were common symptoms in both groups. Women with moderate/severe disease were more likely to have comorbidities (eg, asthma) and were also more likely to have dyspnea and chest pain/pressure. Other symptoms included muscle aches, sore throat, congestion, headache, diarrhea, nausea and loss of taste or smell. Two women had pre-term delivery because of clinical status deterioration; there were no reported deaths. The generally favorable course of Covid-19 among pregnant women has been supported by other studies (2,3,4).
To date, vertical transmission of SARS-CoV-2, the agent of Covid-19 appears rare (2,3,5,6). In one review, only 1 of 75 newborns tested for SARS-CoV-2 infection were positive; this infant did well clinically but had transient lymphocytopenia and abnormal liver function tests (2). A systematic review found no evidence of intrauterine transmission of SARS-CoV-2 (6).
Transmission of SARS-CoV-2 during the first trimester may be unlikely because of expression of ACE2 (a receptor for the virus) in the trophoblasts is very low between 6-14 weeks (7). In a small study examining placenta and fetal membranes in Covid-19 women, 3/11 samples were positive for SARS-CoV-2 but none of the infants tested positive on day 1-5 of life or demonstrated symptoms of Covid-19 (8).
Although another source of perinatal infection is exposure to mother’s secretions during vaginal delivery, so far presence of SARS-CoV-2 in vaginal secretions has not been reported (8). Also encouraging is a study of 18 infants born of women testing positive for SARS-CoV-2, all of whom had normal APGAR scores, with the majority (>80%) testing negative (3).
So overall, the major threat of Covid-19 to the fetus appears to be the severity of illness in the mother. Pregnant women should be familiar with the early symptoms of Covid-19 and seek medical care as soon as possible.
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1. Andrikopoulou M, Madden N, Wen T, et al. Symptoms and critical illness among obstetric patients with coronavirus disease 2019 (COVID-19) infection. OB GYN 2020 https://pubmed.ncbi.nlm.nih.gov/32459701/
2. Zaigham M, Andersson O. Maternal and perinatal outcomes with COVID-19: a systematic review of 108 pregnancies. Acta Obstet Gynecol Scand 2020;00:1-7. https://pubmed.ncbi.nlm.nih.gov/32259279/
3. Breslin 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;100118. https://www.sciencedirect.com/science/article/pii/S2589933320300483
4. Chen L, Li Q, Zheng D, et al. Clinical characteristics of pregnant women with Covid-19 in Wuhan, China. N Engl J Med 2020, April 17. https://www.nejm.org/doi/full/10.1056/NEJMc2009226?af=R&rss=currentIssue
5. Di Mascio D, Khalil A, Saccone G, et al. Outcome of coronavirus spectrum infections (SARS, MERS, COVID-19) during pregnancy: a systematic review and meta-analysis. Am J OB GYN 2020. https://www.sciencedirect.com/science/article/pii/S0002937820305585
6. Yang Z, Liu Y. Vertical transmission of severe acute respiratory syndrome coronavirus 2: A systematic review. Am J Perinatol 2020;10.1055/s-0040-1712161. https://pubmed.ncbi.nlm.nih.gov/32403141/
7. Amouroux A, Attie-Bitach, Martinovic J, et al. Evidence for and against vertical transmission for SARS-CoV-2 (COVID-19). Am J OB GYN 2020. https://www.sciencedirect.com/science/article/pii/S000293782030524X
8. Penfield CA, Brubaker SG, Lighter J. Detection of severe acute respiratory syndrome coronavirus 2 in placental and fetal membrane samples. Am J OB GYN MFM 2020. https://pubmed.ncbi.nlm.nih.gov/32391518/
Disclosures: The listed questions and answers are solely the responsibility of the author and do not necessarily represent the official views of Massachusetts General Hospital, Harvard Catalyst, Harvard University, its affiliate academic healthcare centers, or its contributors. Although every effort has been made to provide accurate information, the author is far from being perfect. The reader is urged to verify the content of the material with other sources as deemed appropriate and exercise clinical judgment in the interpretation and application of the information provided herein. No responsibility for an adverse outcome or guarantees for a favorable clinical result is assumed by the author. Thank you!