Incidence of congenital heart defects in fetuses of diabetic mothers: a retrospective study of 326 cases.

The aim of this study was to quantify the risk of congenital heart disease in diabetic mothers referred for fetal echocardiography. Of 326 diabetic pregnancies seen over a 5-year period, ten (3.1%) resulted in a fetus with congenital heart disease. Nine (90%) of the ten cardiac lesions were identified prenatally, but one fetus had a ventricular septal defect that was overlooked antenatally. Postnatal follow-up was obtained in 312 cases (95.7%). Prenatal echocardiographic examinations were performed at 18-38 weeks of gestation (median 25 weeks) and the median gestational age at diagnosis of congenital heart disease was 22 weeks (range 19-30 weeks). Following the detection of a severe cardiac anomaly, the pregnancy was terminated in three cases. Of the seven continuing pregnancies, two resulted in spontaneous intrauterine death and two babies died within the first 6 months of life. The three survivors are clinically well, but one has required postnatal catheter intervention. Our results confirm that diabetic women are at increased risk of having a baby with congenital heart disease and detailed fetal echocardiography should therefore be offered to all diabetic women during pregnancy.