Esther Martin, 35, of Harrisburg, Pennsylvania, was born with Shone’s anomaly, the constellation of left-heart defects. By age 10, she had had four repairs, followed by aortic valve replacement as an adult, along with a pacemaker implantation for heart block. So when newlywed Martin and her husband wanted to start a family, the decision was anything but casual. “I’ve always wanted to have kids but wasn’t really sure it would be possible,” she says.

Martin’s uncertainty was amplified when a regularly scheduled follow-up only a few months before her wedding revealed a leaky mitral valve. The unexpected twist sent the couple to the altar months earlier than planned.

Within a few weeks of her wedding, Martin was undergoing mitral valve replacement by Duke Cameron, director of cardiac surgery. Mere weeks post-surgery, she was talking baby with pediatric cardiologist Jane Crosson, co-director of the adult congenital heart disease program at Johns Hopkins.

Martin is among the growing number of women born with cardiac defects who attempt pregnancy and successfully carry to term—a testament to parallel successes in pediatric and adult cardiology, cardiac surgery, diagnostic imaging and maternal-fetal medicine.

Because congenital heart defects are spectrum disorders and no two pregnancies are alike, the need for a tailored approach is that much more vital in women with heart defects. “Most can have successful pregnancies provided they have careful preconception counseling and assessment, their condition is well-controlled, they are in good overall health and they are followed carefully,” Crosson says.

To ensure that the heart is coping with the substantially higher cardiac output of pregnancy, exercise stress testing is essential, Crosson says, yet Martin’s pacemaker would have rendered such testing less useful. Instead, she had periodic echocardiograms.

Women with congenital heart disease have a small but real risk of giving birth to a baby with a heart defect—about 5 to 7 percent, compared with 1 percent for the general population. In September 2014, Martin gave birth to a healthy boy.