ArticleThe Lancet regional health. Europe2023
Maternal and perinatal outcomes following pre-Delta, Delta, and Omicron SARS-CoV-2 variants infection among unvaccinated pregnant women in France and Switzerland: a prospective cohort study using the COVI-PREG registry.
Article in The Lancet regional health. Europe, 2023. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 31 papers, 1 of them a synthesis that pooled it.
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Who cites it
31 citing papers in PubMed, 1 synthesis or guideline pooled it.
- Medications Used Among Nonhospitalized Pregnant Women With COVID-19: A Prospective Individual Patient Data Meta-Analysis in Europe and North America.Pharmacoepidemiology and drug safety · 2026Pooled it
- The Role of Vaccination in Maternal and Perinatal Outcomes Associated With COVID-19 in Pregnancy.JAMA · 2026Article
- Postpartum hemorrhage after SARS-CoV-2 infection in pregnancy: A Scandinavian register-based cohort study.Acta obstetricia et gynecologica Scandinavica · 2025Article
- SARS-CoV-2 delta and omicron variants alter trophoblast cell fusion and syncytiotrophoblast dynamics: new insights into placental vulnerability.Cell death & disease · 2025Article
- Safety and efficacy of maternal RSV vaccination: a systematic review and meta-analysis.Clinical and experimental vaccine research · 2025Review
- The WHO Pandemic Agreement: protecting pregnant people.The Lancet. Obstetrics, gynaecology, & women's health · 2025Article
- Incidence, Risk Factors and Outcomes of SARS-CoV-2 Infection in Pregnant Women: The COROPREG Population-Based Study.Paediatric and perinatal epidemiology · 2025Article
- Trends in Maternal, Fetal, and Infant Mortality in the US, 2000-2023.JAMA pediatrics · 2025Article
- Comparing the maternal and neonatal outcomes in vaccinated and unvaccinated pregnant women against COVID-19: a retrospective cohort study.BMC pregnancy and childbirth · 2025Article
- Expanding the OMOP Common Data Model to Support Perinatal Research in Network Studies.Pharmacoepidemiology and drug safety · 2025Article
- Clinical characteristic and outcomes of pregnant women with COVID-19: The PROUDEST prospective cohort study.PloS one · 2025Article
- Impact of COVID-19 in pregnancy on maternal and perinatal outcomes during the Delta variant period: a comparison of the Delta and pre-delta time periods, 2020-2021.Maternal health, neonatology and perinatology · 2024Article
- COVID-19 in Pregnancy: Do Parturients Carry a High Risk of Adverse Maternal and Neonatal Outcomes?Indian journal of critical care medicine : peer-reviewed, official publication of Indian Society of Critical Care Medicine · 2024Article
- COVID-19 diagnosis, vaccination during pregnancy, and adverse pregnancy outcomes of 865,654 women in England and Wales: a population-based cohort study.The Lancet regional health. Europe · 2024Article
- A prospective cohort study of pregnancy outcomes following antepartum infection with SARS-CoV-2.Pregnancy hypertension · 2024Article
- Eighteen-Month Outcomes Among Pregnant and Nonpregnant Reproductive-Aged People Hospitalized for Coronavirus Disease 2019.Open forum infectious diseases · 2024Article
- Management of pregnant women in tertiary maternity hospitals in the Paris area referred to the intensive care unit for acute hypoxaemic respiratory failure related to SARS-CoV-2: which practices for which outcomes?Annals of intensive care · 2024Article
- Vertical transmission of SARS-CoV-2 delta-variant in a preterm infant.BMC infectious diseases · 2024Article
- Seroprevalence and placental transfer of SARS-CoV-2 antibodies in unvaccinated pregnant women.BMC infectious diseases · 2024Article
- Characteristics and outcomes of neonates hospitalised with SARS-CoV-2 infection in the UK by variant: a prospective national cohort study.Archives of disease in childhood. Fetal and neonatal edition · 2024Article
Corrections and comments
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Authors and funding
31 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Background: SARS-CoV-2 positive pregnant women are at higher risk of adverse outcomes, but little evidence is available on how variants impact that risk. We aim to evaluate maternal and perinatal outcomes among unvaccinated pregnant women that tested positive for SARS-CoV-2, stratified by pre-Delta, Delta, and Omicron periods. Methods: This prospective study enrolled women from March 2020 to September 2022. Exposure to the different SARS-CoV-2 variants was defined by their periods of predominance. The primary outcome was severe maternal adverse outcome defined as either intensive care unit admission, acute respiratory distress syndrome, advanced oxygen supplementation, or maternal death. The secondary outcomes were preterm birth and other perinatal outcomes. Findings: Overall, 1402, 262, and 391 SARS-CoV-2 positive pregnant women were enrolled during the pre-Delta, Delta, and Omicron periods respectively. Severe maternal adverse outcome was reported in 3.4% (n = 947/1402; 95% confidence intervals (95%CI) 2.5-4.5), 6.5% (n = 7/262; 95%CI 3.8-10.2), and 1.0% (n = 4/391; 95%CI 0.3-2.6) of women during the pre-Delta, Delta, and Omicron periods. The risk of severe maternal adverse outcome was higher during the Delta vs pre-Delta period (adjusted risk ratio (aRR) = 1.8; 95%CI 1.1-3.2) and lower during the Omicron vs pre-Delta period (aRR = 0.3; 95%CI, 0.1-0.8). The risks of hospitalization for COVID-19 were 12.6% (n = 176/1402; 95%CI 10.9-14.4), 17.2% (n = 45/262; 95%CI 12.8-22.3), and 12.5% (n = 49/391; 95%CI 9.4-16.2), during the pre-Delta, Delta, and Omicron period, respectively. Pregnancy complications occurred after SARS-CoV-2 exposure in 30.0% (n = 363/1212; 95%CI 27.4-32.6), 35.2% (n = 83/236; 95%CI 29.1-41.6), and 30.3% (n = 105/347; 95%CI 25.5-35.4) of patients during the pre-Delta, Delta, and Omicron periods, respectively. Stillbirths were reported in 0.5% (n = 6/1159; 95%CI 0.2-1.1), 2.8% (n = 6/210; 95%CI 1.0-6.0), and 0.9% (n = 2/213; 95%CI 0.1-3.4) or patients during the pre-Delta, Delta, and Omicron periods respectively. Interpretation: The Delta period was associated with a higher risk of severe maternal adverse outcome and the Omicron period with a lower risk of severe adverse outcome compared to pre-Delta era. The reported risk of hospitalization was high during the Omicron period and should not be trivialized. Funding: Swiss Federal Office of Public Health, Fondation CHUV.
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