COVID-19 pandemic effect on early pregnancy: are miscarriage rates altered, in asymptomatic women?

Purpose: To evaluate the effect of the COVID-19 pandemic state on early, first-trimester pregnancies.

Methods: A retrospective cohort study conducted at a university-affiliated fertility center in Montreal, Quebec, since the COVID-19 shut down, March 13 until May 6, 2020. Included: all women who came for a first-trimester viability scan during the study period (Study group) and between March 1, 2019 and May 17, 2019, approximately one year prior (Control). The study population denied symptoms of COVID-19. We reviewed all first trimester scans. Early first-trimester pregnancy outcomes (Viable pregnancy, arrested pregnancy including biochemical pregnancy loss and miscarriage, and ectopic pregnancy) were measured as total number and percentage. A multivariate analysis was performed to control for other potentially significant variables, as was a power analysis supporting sample size.

Results: 113 women came for a first-trimester viability scan in the study period, and 172 in the control period (5-11 weeks gestational age), mean maternal age 36.5 ± 4.5 and 37.2 ± 5.4 years (p = 0.28). Viable clinical pregnancy rate was not different between the two groups (76.1 vs. 80.2% in the pandemic and pre-pandemic groups p = 0.41). No significant difference was seen in the total number of arrested pregnancies (defined as the sum of biochemical, 1st trimester miscarriages, and blighted ova) (22.1 vs. 16.9% p = 0.32), or in each type of miscarriage.

Conclusion: The COVID-19 pandemic environment does not seem to affect early first-trimester miscarriage rates in asymptomatic patients.