(HealthDay)—Women who develop pre-eclampsia earlier in pregnancy may be at increased risk for heart problems soon after giving birth, a new study finds.

"These women should be screened for major cardiovascular risk factors and prevention strategies should be implemented as soon as possible," said study author Dr. GianLuca Colussi. He's an assistant professor of medicine at the University of Udine in Italy.

Pre-eclampsia is a dangerous increase in blood pressure that occurs in the second half of pregnancy.

Researchers assessed heart structure and function in 65 women one month after they gave birth. None had high blood pressure before pregnancy, but developed pre-eclampsia during pregnancy. Thirty-seven percent of them had early onset pre-eclampsia—before the 34th week of pregnancy, the study authors said.

The study also included 16 nonpregnant women with high blood pressure; six healthy pregnant women and 30 healthy nonpregnant women.

Women with pre-eclampsia were more likely than pregnant women without the condition to have thickening of the left heart muscle one month after giving birth. The condition was more severe among women with early onset pre-eclampsia.

The findings show that pregnant women with pre-eclampsia and their doctors need to be aware that there is an increased risk of heart problems after delivery, the researchers said.

"We've shown that women with early onset pre-eclampsia might be at even greater risk," Colussi said in an American Heart Association news release.

More research is needed to determine why women with early onset pre-eclampsia are at increased risk for these heart changes, he said.

The U.S. National Institutes of Health estimates that about 3.4 percent of pregnancies in the United States involve pre-eclampsia.

The study was presented Thursday at a meeting of the heart association and American Society of Hypertension, in San Francisco. Research presented at meetings is usually considered preliminary until published in a peer-reviewed medical journal.

More information: The March of Dimes has more on pre-eclampsia.