Prevalence of COVID-19 among pregnant women and its impact on childbirth in March 2021: Data from the French National Perinatal Survey

Background: Several series reported obstetric complications among pregnant women hospitalized for COVID. These data, because they focused on women with the most severe presentations or with specific immunosuppression, were likely to overestimate the risks associated with the infection at a global level. To date, population-based studies, most of which collected data from registers of women hospitalized during pregnancy for COVID-19, remain sparse. Neither the prevalence of COVID-19 in pregnant women nor the overall extent of obstetric complications worldwide, compared with uninfected pregnant women is clear. The impact of COVID-19 on perinatal care and obstetric management is thus difficult to evaluate.

Objectives: To evaluate the prevalence and determinants of COVID-19 diagnosis during pregnancy and assess related obstetric practices and perinatal outcomes.

Study design: Used data collected at childbirth in France from women included in the 2021 national perinatal survey, we compared women with and without a COVID-19 diagnosis (for sociodemographic characteristics) and then women with no COVID-19 diagnosis during pregnancy, women diagnosed more than 15 days preceding childbirth, and those diagnosed within those 15 days for outcomes.

Results: The COVID-19 prevalence during pregnancy was 5.7 % (95 %CI 5.3-6.1) (678/11 930). The aOR for COVID-19 diagnosis associated with non-French nationality was 1.27 (95 %CI 1.03-1.58), with non-smoking 0.63 (95 %CI 0.55-0.81) and with multiparity 1.21 (95 %CI 1.02-1.45). Diagnosis occurred in the third trimester for 49 % -28.5 % in the 15 days before childbirth. Women with COVID-19 diagnosed during pregnancy had preterm births more often (9.6 %) than women without this diagnosis (6.9 %) (P = 0.007). Women with COVID-19 diagnosed within the 15 days preceding childbirth had more cesarean deliveries (28.3 %) than those diagnosed earlier (17.4 %) (P = 0.02).

Conclusions: COVID-19 diagnosis during pregnancy was associated with an increased risk of preterm birth. Obstetric outcomes were poorer in women with a COVID-19 diagnosis in the 15 days preceding childbirth.