July 22, 2010

Program aids pregnant women who also have congenital heart disease

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May Ling Mah, M.D., specializes in the care of pregnant women with congenital heart disease. (Photo by Joe Howell)

Program aids pregnant women who also have congenital heart disease

Due to medical and surgical advances over the last 50 years, more than 85 percent of people born with congenital heart disease (CHD) can expect to reach an adult age.

With this good news comes the need for specialized care of these adults.

Today about 1 million adults are living with CHD, which encompasses a broad range of defects from a simple hole in the heart to the more complex arterial switch and single ventricle lesions.

Adults with CHD require specialized care from cardiologists with training and expertise in CHD, and the Vanderbilt Heart Adult Congenital Program, led by Larry Markham, M.D., and Ben Byrd, M.D., is poised to be a leader in providing such care. They recently welcomed a new member to their team, May Ling Mah, M.D., who has a special interest in the care of pregnant women with CHD.

Mah came to Vanderbilt in January from a clinical fellowship at Toronto General Hospital. While there, she helped conduct a research study on 600 women with CHD who had babies.
The research team will publish the results this fall.

“On the whole, the women did all right. There were three maternal deaths. There were higher rates of fetal complications, since women with heart disease have smaller babies and earlier deliveries than women without CHD,” Mah said. “If we can manage them from a cardiovascular and obstetrics standpoint, a lot of these women can successfully have children.”

Not so long ago, women with CHD were advised not to have children because it was considered too much of a risk to the mother's health, not to mention the increased risk of passing on the heart defect to the baby.

“For many women, having a baby is one of the most important things they will do in their lives,” said Mah, who gave birth to her first child in March. “On the whole we have made huge strides to pull this off. They will never be low risk, but we can reduce their risk.”

Holly Pierce, ANP-BC, a nurse practitioner, at the Vanderbilt Heart & Vascular Institute, was born with multiple heart defects, including a narrowing of her aorta and a hole in her heart. When Pierce, 35, and her husband began to think about starting a family, she consulted Markham, who ran a battery of tests to make sure her heart was in good shape.

“I was never told that I could not have a baby. Of course, I was concerned if this was going to be passed on to my child, and my husband and I were concerned about my health,” said Pierce, who was seen by Markham throughout her pregnancy.

Her pregnancy was uneventful, and her son is a healthy 18-month-old with no signs of heart trouble.

“If a woman with CHD is otherwise healthy and is able to work and manage an active lifestyle, then I think that predicts that she can do well through pregnancy,” Mah said.

“There are small groups of women who don't do well, such as those with poor functional capacity before pregnancy, with poor muscle function of the heart, and those with pulmonary hypertension. Those three groups of women give me pause when they come in and say they want to be pregnant. Not that those things can't be overcome, but those women have to know the risks versus benefits,” Mah said.

At about 14 week's gestation, a woman's blood volume starts to go up, eventually increasing by 50 percent. The heart rate goes up on average by about 10 beats per minute as well. The heart has to pump more, which takes its toll on a woman with a compromised heart function.

Small studies comparing women with aortic stenosis who were pregnant to women with the same heart disease who were not pregnant indicate a 30 percent to 40 percent increase in the need to have an aortic procedure in the years following pregnancy.

“Pregnancy clearly has a long-term impact on these women, and we're not exactly sure why that is,” Mah said, adding that she plans to continue her research in this area.

Mah has a joint appointment with Pediatric Cardiology and Adult Cardiology. She completed an internship and residency in Internal Medicine and Pediatrics at the University of North Carolina and a fellowship in Pediatric Cardiology at the University of Michigan.

All told, she's had eight years of training and, like her colleagues, is uniquely qualified to follow her patients from childhood through adulthood.

“Vanderbilt is poised to do that because we have collaboration between Pediatric and Adult Cardiology,” she said.