COVID-19 Vaccination Linked to Lower Preeclampsia Risk

A new study found a link between COVID-19 vaccination and a reduced risk of preeclampsia among pregnant women. For healthcare providers, the study suggests that vaccination campaigns could play a role in addressing one of pregnancy’s most persistent risks.

A multinational study by the INTERCOVID consortium reports that COVID-19 vaccination, particularly with a booster dose, is associated with a reduced risk of preeclampsia among pregnant women. The findings connect immunization strategies with broader maternal health outcomes at a time when hypertensive disorders remain a leading cause of maternal mortality worldwide.

Researchers and public health authorities say the results may inform prenatal care strategies, especially for high-risk populations and health systems facing persistent maternal mortality gaps.

Vaccination and Preeclampsia Risk

The study analyzed data from 6,527 pregnant women across 18 countries to examine the relationship between COVID-19 vaccination, SARS-CoV-2 infection and the risk of preeclampsia, a hypertensive disorder of pregnancy with uncertain etiology.

Researchers found that SARS-CoV-2 infection was independently associated with a 45% increase in the risk of preeclampsia. Among unvaccinated women, the risk rose to 78%. Any COVID-19 vaccination showed a protective effect, with an adjusted odds ratio of 0.85. The effect was more pronounced among women who received a booster dose, which reduced the odds of preeclampsia by between 30% and 33%.

The protective association was strongest among women with pre-existing conditions such as diabetes, hypertension, and cardiac disease. In this group, a booster dose reduced the odds of preeclampsia by 58%, effectively narrowing the risk gap with the general population.

Timing also appeared relevant. The protective effect was most evident among women vaccinated during the second or third trimester.

Beyond preeclampsia prevention, the study reported broader maternal and perinatal benefits associated with booster doses. These included a 33% reduction in preterm birth (aOR: 0.67), a 32% reduction in maternal morbidity and mortality (aOR: 0.68), and a 29% reduction in perinatal morbidity and mortality (aOR: 0.71).

The authors note that COVID-19 and preeclampsia share biological pathways, including endothelial damage and inflammatory responses. SARS-CoV-2 can trigger cytokine release and vascular injury, contributing to placental dysfunction and hypoxia. The virus also interacts with angiotensin-converting enzyme 2 (ACE2), which may lead to vasoconstriction and hypertension. Vaccination may mitigate these mechanisms by preventing severe infection or through immune modulation.

The study’s strengths include its large prospective multinational cohort and standardized data collection across 40 sites. However, researchers acknowledge its observational design, potential selection bias in vaccine uptake and smaller sample sizes in certain subgroup analyses.

Maternal Mortality and Systemic Gaps

The findings arrive amid renewed scrutiny of maternal mortality trends. According to the World Health Organization (WHO), severe hemorrhage and hypertensive disorders, including preeclampsia, remain the leading causes of maternal death globally. In 2020, hemorrhage accounted for nearly 80,000 deaths and hypertensive disorders for about 50,000.

An estimated 287,000 maternal deaths occurred worldwide in 2020, equivalent to one death every two minutes. In 2023, global maternal deaths stood at about 260,000, with a maternal mortality ratio (MMR) of 197 per 100,000 live births, above the Sustainable Development Goal (SDG) target of fewer than 70 by 2030.

Nearly two-thirds of global maternal deaths occur in countries affected by conflict or institutional fragility. Countries experiencing conflict recorded an estimated MMR of 504 deaths per 100,000 live births, compared to 99 in more stable settings. WHO officials have emphasized that health system instability, funding pressures, and workforce shortages contribute to preventable maternal deaths.

“Understanding why pregnant women and mothers are dying is critical for tackling the world’s lingering maternal mortality crisis,” says Pascale Allotey, Director of Sexual and Reproductive Health and Research, WHO, in a recent global update published in The Lancet Global Health.

In Mexico, the Ministry of Health recorded 534 maternal deaths in 2024 and 88 in early 2025. Hypertensive disease during pregnancy, abortion and obstetric complications were among the leading causes. Women aged 45 to 49 showed the highest maternal mortality ratio at 164.6 per 100,000 live births.

Preeclampsia affects up to 10% of pregnancies globally and is linked to about 50,000 deaths annually. In Mexico, the National Institute of Perinatology Isidro Espinosa de los Reyes reports an incidence rate of 47.3 cases per 1,000 births.

Health authorities also note long-term cardiovascular consequences for women who experience preeclampsia, including increased risks of hypertension, myocardial infarction, and cerebrovascular events later in life. Follow-up care for five to 10 years postpartum is recommended due to elevated cardiovascular and renal risks.

Policy Responses and Preventive Strategies

Early detection and preventive care play key roles in preventing maternal death, say Mexico’s public health authorities. Screening before the 13th week of gestation can identify women at higher risk, including those with diabetes, obesity, kidney disease, or advanced maternal age. Targeted interventions, such as low-dose acetylsalicylic acid and calcium supplementation under medical supervision, have been associated with up to a 70% reduction in preeclampsia risk among eligible patients.

Regulatory reforms are also underway. NOM-020-SSA-2025 formally integrates professional and traditional midwives into the national health system and establishes midwifery houses and low-risk birthing units. Authorities state the measure aims to expand access and reduce preventable complications, particularly in underserved communities.

Broader maternal health strategies increasingly intersect with chronic disease management. WHO’s first global guidelines on diabetes in pregnancy, released in 2025, address gestational and pre-existing diabetes, which affect an estimated one in six pregnancies. Poor glucose control increases the risk of preeclampsia, prenatal mortality, and long-term cardiometabolic disease in mothers and children.

In Mexico, diabetes is the second leading cause of death, with 112,577 deaths recorded in 2024, according to national statistics. Chronic diseases account for nearly 90% of reported fatalities, underscoring the interaction between noncommunicable diseases and maternal outcomes.

The National Institute of Perinatology Isidro Espinosa de los Reyes has expanded neonatal intensive care capacity and prenatal monitoring programs, emphasizing that maternal conditions such as gestational diabetes and preeclampsia are closely linked to neonatal complications. The Ministry of Health has also launched training courses for primary care physicians under the First 1,000 Days of Life Protocol, covering pregnancy through a child’s second year.

Global agencies estimate that every US$1 invested in maternal and newborn care in low- and middle-income countries can generate a return of US$9 to US$20 through improved health and productivity.

The INTERCOVID findings position COVID-19 vaccination as a potential complementary strategy within this broader maternal health framework. While the study does not establish causality, researchers argue that vaccination, particularly with a booster dose, is associated with significantly lower odds of preeclampsia and improved maternal and perinatal outcomes.

As health systems evaluate pandemic-era lessons, the integration of infectious disease prevention into routine prenatal care may shape future maternal health policy. For healthcare providers, insurers, and public health planners, the data suggest that vaccination campaigns and chronic disease management strategies could play a role in addressing one of pregnancy’s most persistent risks.