Total glycosylated hemoglobin in mothers of large-for-gestational-age infants: a postpartum test for undetected maternal diabetes?

Total glycosylated hemoglobin has been evaluated postpartum using a colorimetric (thiobarbituric acid: TBA) method in 50 mothers of large-for-gestational-age (LGA) infants (greater than 90th percentile by weight). 30 women without potential risk factors for chemical diabetes who gave birth to appropriate-for-gestational-age (AGA) infants formed the control group. When compared to the control mothers, mean total glycosylated hemoglobin (TBA color) levels were significantly higher in the mothers of LGA infants (p less than 0.01). 4 of the latter had an abnormal oral glucose tolerance test (GTT) done within 5 days postpartum and significantly elevated glycosylated hemoglobin compared to mothers of LGA infants with normal GTT (p less than 0.001). Furthermore, a significant linear correlation was found for mothers of LGA infants between TBA color levels and each of the following: fasting serum glucose (p less than 0.001), 1-hour serum glucose (p less than 0.001), 2-hour serum glucose (p less than 0.001), and infant birth weight (p less than 0.05). Analysis of TBA color levels early postpartum might be an alternative method for detecting unsuspected chemical diabetes in pregnancy.