Until recently, pregnancy was discouraged in women who have undergone the so-called "Fontan operation" to correct complex birth defects of the heart. However, case reports and one clinical study suggest that women can become pregnant and deliver healthy infants.

To investigate further, Dr. Willem Drenthen, a cardiologist at the University of Groningen, and his team identified 38 women ages 21 to 58 who had undergone the heart surgery for various congenital heart defects.

Between 1986 and 2003, seven women tried to conceive, and six became pregnant a total of 10 times, which resulted in four live births. There were two premature deliveries, and two infants were small for gestational age.

All four births were accompanied by significant complications, including deterioration in heart function, a dangerous heart arrhythmia called atrial fibrillation, pregnancy-related high blood pressure, premature membrane rupture, premature birth, fetal growth retardation and neonatal deaths. However, the mothers' complications resolved fairly quickly afterwards.

Overall, infertility appears to be frequent in these women; many of the women stopped menstruating, the investigators learned.

The authors reviewed the literature for studies regarding pregnancy after the Fontan operation, which is named after the developer of the procedure. Overall, obstetric complications were common, they report, with 15 of 39 completed pregnancies ending with premature birth.

Drenthen's group concludes that the pregnancy is not likely to cause severe complications among women whose Fontan palliation resulted in adequate repair.

However, based on the high miscarriage rates, other complications during pregnancy, neonatal deaths, and lack of data regarding long-term outcomes, they write, "these problems are important reasons to regard pregnancy as not advisable."

SOURCE: Heart September 2006.