Glycohemoglobin (HbAIc): a predictor of birth weight in infants of diabetic mothers.

Hemoglobins AIa-c (fast Hb), minor variants of HbA, are elevated in patients with diabetes mellitus. Recent studies indicate a relationship of fast hemoglobins, especially HbAIc (glycosylated form), to chronic hyperglycemia. Since infant oversize has been attributed to maternal hyperglycemia and fetal hyperinsulinemia, the hemoglobin HbAIc fraction was compared to birth weight (actual and relative to gestational age) and to maternal glucose tolerance. Normal (13), probably normal (8), gestational diabetic (10), and insulin-dependent women (14) were studied in the third trimester; women with advanced diabetic vascular disease were excluded. When corrected for gestational age, relative birth weights correlated in a significant linear regression with HbAIc (n = 45, r = 0.57, P less than 0.001). Third trimester maternal glucose tolerance (Kt) of women, not insulin dependent, correlated in a signigicant manner with both HbAIc (P less than 0.05) and birth weight for gestational age (P less than 0.01).