Women with chronic hypertension (high blood pressure before pregnancy or diagnosed before 20 weeks of pregnancy) had a 30% higher risk of having a baby with critical congenital heart disease, the most severe form of heart defects, when compared to women with normal blood pressure before and during pregnancy, the Medical Xpress reported, citing a new independent, preliminary research presented at the American Heart Association's Scientific Sessions 2026, held Nov. 6–9 in Chicago.
High blood pressure during pregnancy is defined as systolic blood pressure (the top number) of 140 mm Hg or higher and diastolic blood pressure (the bottom number) of 90 mm Hg or higher. According to the American Heart Association/American College of Cardiology 2025 High Blood Pressure Guideline, high blood pressure affects approximately 16% of pregnancies. It is a leading cause of serious health complications and death for both pregnant individuals and their infants worldwide.
Types of high blood pressure in pregnancy that were included in this study were chronic (preexisting before pregnancy or diagnosed prior to 20 weeks of pregnancy); gestational (diagnosed at 20 weeks of pregnancy or later); chronic with gestational (high blood pressure before or during the first 20 weeks of pregnancy that continues to rise and/or leads to complications); and eclampsia (severe hypertension diagnosed after 20 weeks of pregnancy that includes seizures and other complications and requires emergency treatment).
This study explored maternal health factors to evaluate the potential association between high blood pressure-related disorders during pregnancy and the risk of critical congenital heart disease (CCHD), the most severe type of congenital heart disease, also called congenital heart defects. Infants with CCHD require surgery or catheter placement during the first year of life and continued cardiac specialty care.
The analysis found that maternal hypertension became increasingly common during the study period. The prevalence increased by nearly 48%—rising from approximately 9.4% of pregnancies in 2018 to 13.9% in 2024.
The prevalence of critical congenital heart disease also increased about 10% during the same time period, 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.
"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 in the division of cardiovascular medicine at Lahey Clinic of Beth Israel Lahey Health in Burlington, Massachusetts.
"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."
