Clinical Characteristics and Outcomes of Coronavirus Disease 2019 (COVID-19) in Pregnant Women: A Propensity Score-Matched Analysis of Data From the COVID-19 Registry Japan

Propensity score-matched analysis showed that pregnancy could be a risk factor for moderate-to-severe COVID-19 in Japan. In addition to presence of comorbidities, later gestational age may be associated with severity of COVID-19 in pregnant women. Background Several studies have investigated whether pregnancy is a risk factor for developing severe coronavirus disease 2019 (COVID-19); however, the results remain controversial. In addition, the information regarding risk factors for developing severe COVID-19 in pregnant women is limited. Methods A retrospective cohort study analyzing the data from the nationwide COVID-19 registry in Japan was conducted. Propensity score-matched analysis was performed to compare COVID-19 severity between pregnant and nonpregnant women. Multivariate analysis was also conducted to evaluate risk factors for developing moderate-to-severe COVID-19 in pregnant women. Results During the study period, 254 pregnant and 3752 nonpregnant women of reproductive age were identified. After propensity score matching, 187 pregnant women and 935 nonpregnant women were selected. A composite outcome of moderate-to-severe COVID-19 was more frequently observed in pregnant women than that of nonpregnant women (n = 18 [9.6%] vs n = 46 [4.9%]; P = .0155). In multivariate analysis, the presence of underlying diseases and being in the second-to-third trimester of pregnancy were recognized as risk factors for moderate-to-severe COVID-19 in pregnant women (odds ratio [95% confidence interval]: 5.295 [1.21-23.069] and 3.871 [1.201-12.477], respectively). Conclusions Pregnancy could be a risk factor for moderate-to-severe COVID-19 for women in Japan. In addition to the presence of comorbidities, advanced pregnancy stages may contribute to greater risks for developing moderate-to-severe COVID-19 in pregnant women.