High Maternal Levels of Hemoglobin A_1c Associated with Delayed Fetal Lung Maturation in Insulin-Dependent Diabetic Pregnancies

Abstract

Phosphatidylglycerol (PG) in 227 amniotic fluid specimens obtained by amniocentesis during the third trimester and hemoglobin A_1C (Hb A_1C) in 889 maternal blood specimens obtained between 6 and 39 gestational weeks were measured for 115 singleton insulin-dependent diabetic pregnancies without major fetal malformations or stillbirths. The fetuses of diabetics whose mean Hb A_1C during pregnancy was 8.5% or more remained PG-negative more often than those in the pregnancies with the mean Hb A_1C below 8.5% at 37 (4/7 vs. 8/68, x² = 10.2, p<0.01) and 38 (2/7 vs. 2/84, x² = 5.2, p <0.05) completed weeks of gestation. The fetuses of the patients with a mean Hb A_1C 8.0% or more were more often PG-negative at 37 gestational weeks (7/15) than those in the pregnancies with a mean Hb A_1Cbelow 8.0% (5/60, x² = 10.4, p <0.005). Because Hb A_1C reflects long-term blood glucose levels, the results suggest that maternal hyperglycemia, or other metabolic disturbances associated with hyperglycemia, is the cause of delayed fetal lung maturation among insulin-dependent diabetics.

Key Words:

• Diabetic pregnancy
• fetal lung maturation
• glycosylated hemoglobin
• amniotic fluid phosphatidylglycerol