Coronavirus disease 2019 and first-trimester spontaneous abortion: a case-control study of 225 pregnant patients

The disease caused by the severe acute respiratory syndrome coronavirus 2 was named coronavirus disease 2019 and classified as a global public health emergency. The evidence related to the impact of coronavirus disease 2019 on pregnancy is limited to the second and third trimester of pregnancy, whereas data on the first trimester are scant. Many viral infections can be harmful to the fetus during the first trimester of pregnancy, and whether severe acute respiratory syndrome coronavirus 2 is one of them is still unknown.

With this study, we evaluated severe acute respiratory syndrome coronavirus 2 infection as a risk factor for early pregnancy loss in the first trimester of pregnancy. Furthermore, coronavirus disease 2019 course in the first trimester was assessed.

Between February 22 and May 21, 2020, we conducted a case-control study at S. Anna Hospital, Turin, among pregnant women in their first trimester, paired for last menstruation. The cumulative incidence of coronavirus disease 2019 was compared between women with spontaneous abortion (case group, n=100) and those with ongoing pregnancy (control group, n=125). Current or past infection was determined by the detection of severe acute respiratory syndrome coronavirus 2 from nasopharyngeal swab and severe acute respiratory syndrome coronavirus 2 immunoglobulin G and immunoglobulin M antibodies in a blood sample. Patient demographics, coronavirus disease 2019-related symptoms, and the main risk factors for abortion were collected.

Of 225 women, 23 (10.2%) had a positive test result for coronavirus disease 2019. There was no difference in the cumulative incidence of coronavirus disease 2019 between the cases (11/100, 11%) and the controls (12/125, 9.6%) (P=.73). Logistic regression analysis confirmed that coronavirus disease 2019 was not an independent predictor of early pregnancy loss (odds ratio, 1.28; confidence interval, 0.53-3.08). Coronavirus disease 2019-related symptoms in the first trimester were fever, anosmia, ageusia, cough, arthralgia, and diarrhea; no cases of pneumonia or hospital admission owing to coronavirus disease 2019-related symptoms were recorded. No difference in the incidence of symptoms was noted between the 2 groups.

Severe acute respiratory syndrome coronavirus 2 infection during the first trimester of pregnancy does not seem to predispose to early pregnancy loss; its cumulative incidence did not differ between women with spontaneous abortion and women with ongoing pregnancy. Coronavirus disease 2019 appears to have a favorable maternal course at the beginning of pregnancy, consistent with what has been observed during the second and third trimesters.