Women who were born with certain congenital heart defects, even if they have been repaired, have an increased risk of complications during pregnancy for both themselves and the baby. But with proper monitoring by both a cardiologist and a high-risk pregnancy specialist, many women who were once told they shouldn't have children do all right.

"Most women, with close management, can be successfully pregnant," says cardiologist Dr. Kevin Whitehead of University Hospital. "In general, the conditions that are highest risk are something that need to be evaluated before pregnancy, but it's not common to have to recommend not being pregnant."

The first part of pregnancy is not much different for women with a history of congenital heart problems. But by the third trimester, the body undergoes big changes and stresses, even in women with no such history. Most women who are pregnant find their heart rhythms change, they retain fluid and they feel short of breath. The volume of blood the heart must pump nearly doubles. And the risk for problems, some very dangerous, increases.

In fact, say Whitehead and colleague Dr. Mark Brann, medical director of the Adult Congenital Heart Clinic at the University of Utah, some of the women born with heart problems develop severe high blood pressure in the lungs, which can be associated with 50 percent mortality for the mother and 80 percent for the baby, for example. For other complications, risk may be only moderate but bears watching.

About 1 in 125 babies is born with a heart abnormality. Many of them have heart repairs, and as they age they figure they're just fine. They may not know that complications can rear years later during pregnancy, threatening mom, baby or both. That's why heart specialists recommend that those women see a heart specialist, preferably before becoming pregnant.

Alyssa (who asked that her last name not be used) was born 29 years ago with a transposition of the great vessels, meaning that her pulmonary arteries and her aorta were essentially switched. Her deoxygenated blood was returning from her body to her heart, then going back into her body again. She had a small hole in the lower part of her heart, so that blood with oxygen mixed with the deoxygenated blood, providing her blood with some oxygen, but not enough. When she was six months old, surgeons operated.

It wasn't until shortly after she married that her cardiologist told her any pregnancy might be high-risk for complications. He divided his patients into three groups: "Go ahead, you're fine." "If you want to have children, we'll have to watch you closely." And "No way." Alyssa fell into the middle group.