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)

Acta Obstet Gynecol Scand. 2023 Nov;102(11):1521-1530. doi: 10.1111/aogs.14643. Epub 2023 Aug 18.


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 (I2 = 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.

Keywords: COVID-19; SARS-CoV-2; hospitalization; neonate; obstetric surveillance system; pregnancy.

MeSH terms

  • Anticoagulants
  • COVID-19* / epidemiology
  • COVID-19* / therapy
  • Cohort Studies
  • Europe / epidemiology
  • Female
  • Hospitalization
  • Humans
  • Infant
  • Pandemics
  • Pregnancy
  • Pregnancy Complications, Infectious* / epidemiology
  • Pregnancy Complications, Infectious* / therapy
  • Pregnant Women
  • Prospective Studies
  • SARS-CoV-2
  • Venous Thromboembolism* / epidemiology


  • Anticoagulants