Fetal echocardiographic screening of diabetic pregnancies for congenital heart disease.

This study sought to assess pregnant diabetic women for the presence of fetal cardiac anomalies and to determine whether better diabetic control was associated with a reduced risk to the fetus. Between 1988 and 1995, pregnant type I and II diabetic women routinely underwent fetal echocardiography. Hemoglobin A1c values were used as an indicator of maternal diabetic control and any relation between congenital heart disease in the fetus and maternal hemoglobin A1c levels was sought. Cardiac defects were identified in 7 of 328 pregnancies assessed, for an incidence of congenital heart disease of 2.1% (95% confidence interval: 0.6-3.6%). A review of the postnatal cardiac database did not reveal any undetected major malformations. The mean hemoglobin A1c level was 7.6% +/- 2.0% obtained at a mean gestational age of 12 +/- 7 weeks. Hemoglobin A1c levels of mothers carrying a fetus with congenital heart disease did not significantly differ from those with a normal fetus: 8.1% +/- 3.4% versus 7.6% +/- 1.9% (p = 0.48). Mothers with an affected fetus demonstrated a wide range of HbA1c levels (4.1 to 13.7%). Thus, the incidence of significant fetal cardiac abnormalities is low and not significantly related to maternal diabetic control.