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

BACKGROUND: The disease caused by the "severe acute respiratory syndrome coronavirus 2" (SARS-CoV-2) was named Coronavirus Disease 19 (COVID-19) and classified as a global public health emergency. The evidence related to the impact of COVID-19 on pregnancy are limited to the second and the third trimester of pregnancy, while data on the first trimester are scant. Many viral infections can be harmful to the fetus during the first trimester of pregnancy, and whether SARS-CoV-2 is one of them is still unknown.OBJECTIVE(S): With this study we evaluated SARS-CoV-2 infection as a risk factor for early pregnancy loss in first trimester of pregnancy. Furthermore, COVID-19 course in the first trimester was assessed.STUDY DESIGN: Between February 22 and May 21, 2020, we conducted a case-control study at S. Anna Hospital, Turin, among first trimester pregnant women, paired for last menstruation. The cumulative incidence of COVID-19 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 detection of SARS-CoV-2 from nasopharingeal swab and SARS-CoV-2 IgG/IgM antibodies in blood sample. Patient demographics, COVID-19-related symptoms, and the main risk factors for abortion were collected.RESULTS: Twenty-three of the 225 women (23/225, 10.2%) tested positive for COVID-19 infection. There was no difference in the cumulative incidence of COVID-19 between the cases (11/100, 11%) and the controls (12/125, 9.6%) (p=0.73). Logistic regression analysis confirmed that COVID-19 was not an independent predictor of early pregnancy loss (Odd Ratio 1.28, confidence interval 0.53-3.08). COVID-19 related symptoms in the first trimester were fever, anosmia, ageusia, cough, arthralgia and diarrhea; no pneumonia or Hospital admission due to COVID-19-related symptoms were recorded. No difference in the incidence of symptoms was noted between the two groups.CONCLUSION(S): SARS-CoV-2 infection during the first trimester of pregnancy does not appear to predispose to early pregnancy loss; its cumulative incidence did not differ between women with spontaneous abortion and women with ongoing pregnancy. COVID-19 appears to have a favorable maternal course at the beginning of pregnancy, consistent with what has been observed during the second and the third trimester.