Clinical characteristics of pregnant women infected with Coronavirus Disease 2019 in China: a nationwide case-control study

OBJECTIVE To formally compare the clinical course of Coronavirus disease 2019 (COVID-19) in pregnant women with their nonpregnant counterparts. METHODS Clinical data of pregnant women with confirmed COVID-19 in the designated hospitals of mainland China were retrieved up to April 12, 2020 through an epidemic reporting system maintained at the National Health Commission of the People's Republic China. Each pregnant patient was randomly matched to a nonpregnant woman with confirmed COVID-19 in the same hospital as control, then their clinical courses were formally compared. RESULTS 138 pregnant women had been identified as confirmed COVID-19 cases. Among them, 17 severe cases and 1 maternal death were recorded, which was less than their nonpregnant peers (23 severe cases and 3 death). 57.2% had been infected with SARS-CoV-2 during the third trimester, including 13 severe cases and 1 maternal death. 7.3% of pregnant patients had diarrhea and 3.6% had nausea or vomiting, compared with related proportion as 15.2% (OR: 0.38, 95%CI: 0.15, 0.96) and 10.1% (OR: 0.25, 95%CI: 0.07, 0.89) in nonpregnant patients. Pregnant patients infected with SARS-CoV-2 in early pregnancy presented similar laboratory tests with their nonpregnant peers, however, with pregnancy progresses, increased inflammation, coagulation and hepatic injury markers happened more and more frequently (p<0.001) in pregnant patients. CONCLUSIONS Being pregnant did not represent a risk for severe condition when compared with their nonpregnant peers. Patients infected with SARS-CoV-2 in early pregnancy were even at lower risk of severe illness than those infected in late pregnancy.