Recent research suggests a significant link between COVID-19 vaccination during pregnancy and a reduced risk of preeclampsia, a potentially dangerous complication characterized by high blood pressure and reduced blood flow to the fetus. The findings, stemming from a large-scale observational study, offer encouraging news for expectant mothers and reinforce public health recommendations regarding vaccination.
Preeclampsia affects an estimated 3 to 8% of pregnancies globally and remains a leading cause of both maternal and neonatal morbidity and mortality. Understanding and mitigating risk factors for this condition is therefore a critical area of research. This new evidence adds to a growing body of knowledge demonstrating the protective benefits of COVID-19 vaccination extending beyond preventing severe illness in the mother.
The study, conducted by the INTERCOVID consortium led by the University of Oxford and published in eClinicalMedicine, analyzed data from 6,527 pregnant women recruited across 18 countries – including the United States, Europe, Latin America, Africa, and Asia – between 2020 and 2022. This broad geographic representation underscores a concerted global effort to understand maternal and perinatal outcomes during the pandemic. Researchers found that those who received a booster dose of a COVID-19 vaccine experienced a 33% reduction in preeclampsia risk. The benefit was even more pronounced among women with pre-existing health conditions, such as diabetes, hypertension, or thyroid disorders.
The data revealed a strong association between SARS-CoV-2 infection during pregnancy and an increased risk of preeclampsia – a 45% increase rising to 78% among unvaccinated women. In stark contrast, the risk was reduced by 33% in those who had received a booster dose. “These results move beyond the already known benefits of COVID-19 vaccination during pregnancy,” stated José Villar, principal investigator of the INTERCOVID consortium at the University of Oxford. “Now we have evidence that maternal vaccination can influence pathways involved in the development of preeclampsia, suggesting a broader immunological or vascular benefit.”
Understanding the Link Between COVID-19 and Preeclampsia
Researchers have long recognized shared physiological mechanisms between COVID-19 and preeclampsia, including endothelial damage, systemic inflammation, and vascular dysfunction. The vascular damage induced by SARS-CoV-2 can exacerbate the prothrombotic and antiangiogenic environment characteristic of preeclampsia, increasing the risk of hypertensive and placental complications. The study suggests vaccination may mitigate this inflammatory and vascular damage associated with infection, impacting both blood pressure regulation and viral entry into cells.
The protective effect of vaccination isn’t solely attributed to preventing infection. “It’s a complex issue and may involve several mechanisms that will be the subject of future investigations,” explained Villar. “The important thing is that it’s not always necessary to know all the biological details to recommend a public health measure that, if confirmed, could have a very important impact. It wasn’t necessary to understand the exact mechanism by which smoking causes lung cancer to recommend that people not smoke.”
Implications for Pregnant Individuals
The study’s findings support current recommendations for COVID-19 vaccination during pregnancy, particularly for those with pre-existing conditions that increase their risk of preeclampsia. “These results support the vaccination of all pregnant women according to local regulations, especially those with pre-existing problems related to preeclampsia,” Villar emphasized. “The first objective is to implement the regulations and ensure that, in addition to the primary effect, there are likely to be other non-minor benefits.”
Researchers are planning a large-scale, multicenter, international randomized controlled trial to further confirm these findings. “This represents complex and requires careful design, but could be carried out in a relatively short period of time. The potential magnitude of the effect warrants serious consideration by health authorities,” Villar added.
Reference: Paolo Ivo Cavoretto, José Villar, Antonio Farina, Marta Fabre et al. “COVID-19 vaccination status during pregnancy and preeclampsia risk: the pandemic-era cohort of the INTERCOVID consortium”. eClinicalMedicine, 2026.
This research adds to the growing evidence base supporting COVID-19 vaccination as a crucial component of prenatal care. As the scientific community continues to investigate the complex interplay between COVID-19, vaccination, and pregnancy outcomes, staying informed and following the guidance of healthcare professionals remains paramount.
Have you discussed COVID-19 vaccination with your healthcare provider during pregnancy? Share your thoughts in the comments below.
Disclaimer: This article provides informational content and should not be considered medical advice. Always consult with a qualified healthcare professional for personalized guidance regarding your health and treatment options.
