Clinical characteristics of pregnant women with COVID-19 in Japan: a nationwide questionnaire survey

Abstract Objective: To describe the clinical characteristics and outcomes of pregnant women with coronavirus disease (COVID‑19) on a national scale in Japan. Design: A nationwide questionnaire-based survey forwarded to all 2185 maternity services in Japan. Setting: A total of 1418 obstetric units that responded (65% of all delivery institutions in Japan). Population: Pregnant women with COVID-19 diagnosed between January and June 2020. Methods: Data were extracted from the questionnaire results. Main outcome measures: Incidence of pregnant women with COVID-19 and infant infection, positive rate of the universal screening test for asymptomatic pregnant women, identification of infection route, and rates of maternal death, severe cases, and caesarean sections. Results: Seventy-two pregnant women were reported to be diagnosed with COVID-19. The positive rate of the universal screening test for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) for asymptomatic pregnant women was 0.03% (2/7428). The most common route of infection was familial (57%). Fifty-eight pregnant women with COVID-19 were symptomatic; of whom five (8.6%) had a severe infection and one patient died (a tourist). Severe respiratory symptoms, oxygen administration, and pneumonia were frequently reported in the third trimester and postpartum period compared to early pregnancy (22.2% vs. 2.5% [p=0.03], 38.9% vs. 7.5% [p=0.01], and 50.0% vs. 7.5% [p<0.01], respectively). All pregnant women with COVID-19 underwent caesarean section, regardless of symptoms. There was no SARS-CoV-2 transmission to the newborns. Conclusion: The importance of infection prevention should be emphasized, especially in pregnant women, their families, and their roommates during late pregnancy.