Swedish researchers have uncovered compelling evidence that pregnancy complications may serve as early warning signs for cardiovascular disease risk that extends beyond the affected women to their close female relatives, particularly sisters.
The large-scale study, led by Associate Professor Ängla Mantel from the Karolinska Institute in Sweden, analyzed medical records of more than 1.2 million Swedish women who were free of heart disease at the study's commencement. The research team tracked participants for a median of 14 years to assess long-term cardiovascular outcomes.
"It may be important to identify [all of] these women early to offer preventive treatment for pregnancy complications as well as lifestyle counseling and follow-up for cardiovascular disease risk," explained Mantel, highlighting the clinical significance of the findings published in the European Heart Journal on February 7, 2025.
Genetic Component to Cardiovascular Risk
The study included nearly 166,000 women with histories of pregnancy complications such as preeclampsia and premature delivery, along with approximately 61,000 of their sisters who had never experienced such complications themselves.
As expected, women who had experienced pregnancy complications showed elevated risks of cardiovascular issues compared to those with uncomplicated pregnancies. However, the novel finding was that their sisters—even those who had never experienced pregnancy complications—faced a 40% higher risk of heart problems during the follow-up period compared to women without family histories of pregnancy complications.
"The risk of cardiovascular disease after a pregnancy complication does not depend solely on the pregnancy itself, but can be influenced by genes and environmental factors," Mantel noted. This suggests that pregnancy complications may serve as markers for underlying genetic predispositions to cardiovascular disease that run in families.
Twin Pregnancies Amplify Cardiovascular Risks
In a related study also published in the European Heart Journal, researchers from Rutgers Robert Wood Johnson Medical School examined data from over 36 million U.S. hospital deliveries between 2010 and 2020. They found that women who delivered twins faced nearly double the risk of hospitalization for heart problems within a year compared to those who delivered singletons.
The hospital readmission rate for cardiac issues was 1,105 per 100,000 deliveries for twin births versus 734 per 100,000 for singleton pregnancies. This translated to a 95% increased risk of hospitalization for various heart conditions, including heart disease, heart attack, stroke, heart failure, and irregular heart rhythm.
"The maternal heart works harder for twin pregnancies than for singleton pregnancies, and it takes weeks for the maternal heart to return to its pre-pregnancy state," explained Dr. Ruby Lin, lead researcher and maternal-fetal medicine fellow.
Hypertension Dramatically Increases Risk
The risk profile becomes even more concerning when hypertensive disorders of pregnancy are involved. Among mothers of twins who also experienced high blood pressure during pregnancy, the risk of requiring hospitalization for heart problems increased more than eightfold.
For mothers of singletons with pregnancy-related hypertension, the risk was nearly six times higher than for those without hypertensive complications.
Professor Cande Ananth, senior researcher on the twin pregnancy study, expressed concern about these findings, noting that "the rate of twin pregnancies worldwide has risen in recent decades, driven by fertility treatments and older maternal age."
Clinical Implications and Recommendations
These studies highlight the importance of extended cardiovascular monitoring for women following complicated pregnancies, as well as potentially screening their close female relatives for cardiovascular risk factors.
Dr. Lin recommends that patients undergoing fertility treatments, especially those with existing cardiovascular risk factors such as advanced age, obesity, diabetes, hypertension, or heart disease, should be counseled about the potential short-term cardiovascular risks associated with twin pregnancies.
"Given these higher risks, healthcare providers and health insurance companies should continue to provide follow-up for up to a year after birth for high-risk pregnancies such as twin pregnancies," Lin advised.
The findings suggest that pregnancy complications could serve as early warning signs for cardiovascular disease risk, providing an opportunity for earlier intervention and prevention strategies not only for the women who experience these complications but potentially for their female relatives as well.
Healthcare providers may need to consider family history of pregnancy complications when assessing cardiovascular risk in women, even if they themselves have not experienced such complications. This approach could lead to more personalized and effective preventive strategies for cardiovascular disease in women.
