Is pregnancy in diabetic women associated with folate deficiency?

To determine whether folate metabolism in pregnant diabetic women is significantly different from that in pregnant nondiabetic women, thus predisposing them to having offspring with major congenital anomalies.

A total of 31 pregnant diabetic women and 54 pregnant nondiabetic control subjects were studied at their first prenatal visits. Dietary folate intake, serum folate, red blood cell folate, urinary folate, and homocysteine were measured and compared after controlling for folate supplementation. Among diabetic women the relationships among parameters of folate metabolism and glycemic control were also assessed.

There were no significant differences between the pregnant diabetic and non-diabetic women for any measures of folate metabolism after accounting for folate supplementation. In addition, among diabetic women, there were no associations among parameters of folate metabolism and glycemic control.

Abnormal folate metabolism does not appear to occur in pregnant diabetic women. It is unlikely that deranged folate metabolism explains the higher incidence of major anomalies in infants of diabetic mothers. These results do not diminish the importance of periconception folate supplementation or preclude other possible scenarios that could restrict folate use by the embryo, leading to congenital anomalies.