Maternal Hypertension and Diabetes Linked to Higher Risk of Severe Fetal Heart Defects, Study Finds

A new analysis of more than 44 million U.S. births from 2018 to 2024 has found that women with chronic hypertension—high blood pressure before pregnancy or diagnosed before 20 weeks—were 30% more likely to deliver an infant with critical congenital heart disease (CCHD), the most severe form of heart defects. The preliminary research, presented at the American Heart Association’s Scientific Sessions 2026, also found that women with Type 1 or Type 2 diabetes before pregnancy had a 48% increased risk of having babies with severe heart defects compared to women without diabetes.

The study, which examined data from the CDC’s National Vital Statistics System, highlights a growing concern: maternal hypertension became increasingly common during the study period, rising from approximately 9.4% of pregnancies in 2018 to 13.9% in 2024—a nearly 48% increase. The prevalence of CCHD also rose about 10% during the same timeframe, from 5.8 cases per 10,000 births in 2018 to 6.4 cases per 10,000 births in 2023-2024, representing nearly 4,000 infants in the U.S. each year. According to the American Heart Association/American College of Cardiology 2025 High Blood Pressure Guideline, high blood pressure affects approximately 16% of pregnancies and is a leading cause of serious health complications and death for both pregnant individuals and their infants worldwide.

“Our findings suggest that maternal heart health before and during pregnancy may have a particularly important relationship with fetal heart development,” said study author Saad Ur Rahman, M.D., chief cardiology fellow at Lahey Clinic of Beth Israel Lahey Health. “These results emphasize the importance of monitoring blood pressure, discussing heart health with clinicians and receiving appropriate care before and during pregnancy to reduce the risk of fetal heart defects.” The study explored various types of high blood pressure in pregnancy, including chronic, gestational, and eclampsia.

Gestational hypertension, diagnosed after 20 weeks of pregnancy, was associated with an 8% increased likelihood of CCHD, while eclampsia was not significantly associated with the condition. “This study adds to a growing body of evidence linking maternal health and the intrauterine environment with fetal cardiovascular development,” said Flora Nuñez Gallegos, M.D., M.P.H., a pediatric cardiologist at University of California San Francisco and a member of the American Heart Association’s Young Hearts Council. “Although the absolute risk of critical congenital heart disease remains low, these findings highlight the importance of identifying and managing chronic hypertension before and during pregnancy.”

The implications for Texas, which has one of the highest birth rates in the country, are significant. With maternal hypertension on the rise, healthcare providers and businesses that support maternal and child health may need to prioritize preconception counseling and cardiovascular screening. The findings also underscore the need for continued research into the biological mechanisms linking maternal high blood pressure to congenital heart disease. The study’s limitations include its observational design and reliance on birth certificate data, which may not capture factors such as genetic history or treatment adherence. The full abstract is available, and additional resources can be found on heart.org and stroke.org.