Depression during pregnancy may be linked to heart disease as soon as two years later, new research suggests.

This is true even when patients don't have high blood pressure during pregnancy, the research team reports April 19 in the Journal of the American Heart Association.

"We need to use pregnancy as a window to future health," said lead study author Dr. Christina Ackerman-Banks, assistant professor of obstetrics and gynecology-maternal fetal medicine at Baylor College of Medicine and Texas Children's Hospital in Houston.

"Complications during pregnancy, including prenatal depression, impact long-term cardiovascular health," she said in a journal news release. "The postpartum period provides an opportunity to counsel and screen people for cardiovascular disease in order to prevent these outcomes."

About 20% of women experience depression during pregnancy, the researchers noted. They shouldn't panic as the study doesn't prove a direct cause-and-effect relationship between depression and heart disease, only an association.

Researchers found the most significant association was between depression and ischemic heart disease (narrowed arteries), with depressed women having an 83% higher risk of developing the condition within two years of delivery than those without a depression diagnosis. When arteries are narrowed, less blood and oxygen reach the heart muscle. This can lead to heart attack, the American Heart Association explains.

"I recommend that anyone diagnosed with prenatal depression be aware of the implications on their long-term cardiovascular health, take steps to screen for other risk factors and consult with their primary care doctor in order to implement prevention strategies for cardiovascular disease," Ackerman-Banks said.

"They should also be screened for type 2 diabetes and high cholesterol, and implement an exercise regimen, healthy diet and quit smoking," she added.

While it's well-established that depressed men and women are more likely to develop heart disease later in life, little research has been done on prenatal depression.

For this study, the researchers analyzed data from an insurance claims database for more than 100,000 women who gave birth in Maine between 2007 and 2019.

The team adjusted for potential confounding factors such as smoking; age at time of delivery; the pregnancy complication preeclampsia; and pre-pregnancy diabetes, depression and hypertension. Then they estimated the risk of developing six major heart conditions: heart failure, narrowed arteries, arrhythmia/cardiac arrest, cardiomyopathy, stroke and high blood pressure within two years of delivery.

The estimated cumulative heart disease risk was significantly higher for people with depression than those without it, researchers found.

Those with depression had not only an 83% higher risk of narrowed arteries but a 60% higher risk of arrhythmia/cardiac arrest (electrical problems of the heart) and a 61% higher risk of cardiomyopathy (a disease of the heart muscle). They also had a 32% higher risk of a new high blood pressure diagnosis.

After excluding those with high blood pressure during pregnancy, researchers found that women with prenatal depression had an 85% higher risk for arrhythmia/cardiac arrest, an 84% higher risk of narrowed arteries, a 42% higher risk of stroke, a 53% higher risk of cardiomyopathy and a 43% higher risk of a new high blood pressure diagnosis.

The heart association notes that heart disease is the leading cause of pregnancy-related death in high-income countries, including the United States. Other pregnancy-related problems, such as chronic inflammation and increased stress-related hormones, may also contribute to heart disease, the study authors said.

The study was funded by the U.S. National Institutes of Health.