A recent study from the INTERCOVID Consortium, which included Ann & Robert H. Lurie Children’s Hospital of Chicago, has found that COVID-19 vaccination during pregnancy can significantly reduce the risk of preeclampsia. This effect is particularly strong when pregnant women receive a booster dose. The research provides new information about preventing preeclampsia, independent of whether the mother was infected with COVID-19.
The study, published in eClinicalMedicine, examined data from 6,527 pregnant women in 18 countries between 2020 and 2022. Researchers compared vaccinated and unvaccinated women—both those who had and had not contracted SARS-CoV-2—to determine how vaccination status affected rates of preeclampsia.
“Our results support the importance of strengthening COVID vaccination programs during pregnancy, emphasising boosters and ensuring that pregnant people across the world have equitable access to the vaccine,” said study co-author Jagjit S. Teji, MD, a neonatologist at Lurie Children’s and Clinical Assistant Professor of Pediatrics at Northwestern University Feinberg School of Medicine. “We offer evidence from the first large study suggesting that COVID vaccination may protect against one of the most serious pregnancy complications.”
The researchers found that COVID-19 infection during pregnancy was linked to a 45% higher risk of developing preeclampsia; this increased to 78% among unvaccinated women. Women who received a booster dose saw their overall odds for preeclampsia fall by 33%. Among those with conditions such as diabetes or hypertension, receiving a booster cut preeclampsia risk by 42%. The reduction in risk remained after accounting for other factors and may apply even without COVID-19 infection.
Vaccinated women also had lower chances of preterm delivery as well as reduced maternal and perinatal health risks. For those who received a booster dose, protection against preterm birth was estimated at 33%, while reductions for maternal morbidity and mortality stood at 32%, and severe perinatal morbidity and mortality at 29%.
“These results go beyond the known benefits of COVID-19 vaccination in pregnancy,” said Professor José Villar, senior co-author and Principal Investigator of the INTERCOVID consortium from the Nuffield Department of Women’s & Reproductive Health at University of Oxford (UK). “We now have evidence that maternal vaccination may influence pathways involved in preeclampsia development, suggesting a broader immunological or vascular benefit of vaccination.”
Preeclampsia affects an estimated 3%-8% of pregnancies worldwide and is a leading cause of illness or death for mothers and newborns. Its origins are not fully understood but are thought to involve inflammation and problems with blood vessels—mechanisms also associated with COVID-19 infection.
The findings suggest that vaccines could help regulate immune responses or blood vessel function related to preeclampsia—even outside their intended purpose.
The INTERCOVID consortium includes more than 40 hospitals in 18 countries. Ann & Robert H. Lurie Children’s Hospital of Chicago participated as part of its ongoing commitment to advancing pediatric care through research.
Ann & Robert H. Lurie Children’s Hospital promotes family-centered care for children’s medical, emotional, and developmental needs (https://www.luriechildrens.org). It operates its main campus in downtown Chicago along with outpatient centers throughout the region (https://www.luriechildrens.org). The hospital has been recognized nationally for excellence in pediatric specialties by U.S. News & World Report (https://www.luriechildrens.org) and serves as the primary teaching affiliate for Northwestern University Feinberg School of Medicine (https://www.luriechildrens.org). With over 70 pediatric specialties represented (https://www.luriechildrens.org), Lurie Children’s focuses on clinical service delivery, specialist training, innovative research—including through Stanley Manne Children’s Research Institute—and comprehensive family support (https://www.luriechildrens.org).
