Women who have had an operation in infancy to correct a congenital heart defect can have a successful pregnancy, but it carries a risk of subsequent heart problems, a Canadian group has found.

A fetal deformity called transposition of the great arteries, in which the aorta is connected to the right ventricle of the heart and the pulmonary artery to the left ventricle - instead of vice versa - can be corrected with a surgical procedure called the Mustard operation.

However, dysfunction of the right ventricle “remains a continuing problem” in these cases, Dr. Antoine Guedes from the Montreal Heart Institute in Quebec and colleagues explain in the Journal of the American College of Cardiology. “Concerns exist about the potentially deleterious effects of pregnancy on this ventricle.”

The team reviewed the records of 16 women who had undergone the Mustard procedure and had completed 28 pregnancies.

They found that six of the women suffered a reduction in functional level during seven pregnancies, and in two cases it did not return to pre-pregnancy levels after delivery.

The data also showed that five women suffered enlargement of the right ventricle during seven pregnancies, with no return to pre-pregnancy dimensions at their last examination.

Based on their findings, the investigators say it “seems reasonable” not to discourage women who have had a Mustard operation from having children if they have a good exercise capacity, and normal or near normal right ventricle function.

“These women must, however, be made aware of the possibility of right ventricle dysfunction occurring with pregnancy and that this deterioration may occur at their first pregnancy,” they emphasize, “and that it might not be reversible after delivery

SOURCE: Journal of the American College of Cardiology, July 21, 2004.