Variations across Europe in hospitalization and management of pregnant women with SARS‐CoV‐2 during the initial phase of the pandemic: Multi‐national population‐based cohort study using the International Network of Obstetric Survey Systems (INOSS)

INTRODUCTION: The majority of data on COVID‐19 in pregnancy are not from sound population‐based active surveillance systems. MATERIAL AND METHODS: We conducted a multi‐national study of population‐based national or regional prospective cohorts using standardized definitions within the International Network of Obstetric Survey systems (INOSS). From a source population of women giving birth between March 1 and August 31, 2020, we included pregnant women admitted to hospital with a positive SARS‐CoV‐2 PCR test ≤7 days prior to or during admission and up to 2 days after birth. The admissions were further categorized as COVID‐19‐related or non‐COVID‐19‐related. The primary outcome of interest was incidence of COVID‐19‐related hospital admission. Secondary outcomes included severe maternal disease (ICU admission and mechanical ventilation) and COVID‐19‐directed medical treatment. RESULTS: In a source population of 816 628 maternities, a total of 2338 pregnant women were admitted with SARS‐CoV‐2; among them 940 (40%) were COVID‐19‐related admissions. The pooled incidence estimate for COVID‐19‐related admission was 0.59 (95% confidence interval 0.27–1.02) per 1000 maternities, with notable heterogeneity across countries (I (2) = 97.3%, P = 0.00). In the COVID‐19 admission group, between 8% and 17% of the women were admitted to intensive care, and 5%–13% needed mechanical ventilation. Thromboprophylaxis was the most frequent treatment given during COVID‐19‐related admission (range 14%–55%). Among 908 infants born to women in the COVID‐19‐related admission group, 5 (0.6%) stillbirths were reported. CONCLUSIONS: During the initial months of the pandemic, we found substantial variations in incidence of COVID‐19‐related admissions in nine European countries. Few pregnant women received COVID‐19‐directed medical treatment. Several barriers to rapid surveillance were identified. Investment in robust surveillance should be prioritized to prepare for future pandemics.