Glycosylated haemoglobin in cord blood following normal and diabetic pregnancies.

Cord and maternal blood samples were obtained at delivery in 25 normal and 14 diabetic pregnancies (13 insulin-dependent, one gestational). Total glycosylated haemoglobin, measured by the colorimetric thiobarbiturate method (mmol hydroxymethylfurfural/mol haemoglobin), was lower in cord than maternal blood (mean 18.7 +/- 1.7 versus 26.5 +/- 2.1, mean +/- SD, p less than 0.001). Glycosylated haemoglobin was higher following diabetic pregnancies, both in cord (diabetic 19.9 +/- 1.6 versus normal 17.9 +/- 1.4, p less than 0.001) and maternal samples (diabetic 27.7 +/- 1.5 versus normal 25.6 +/- 2.1, p less than 0.005). Cord and maternal glycosylated haemoglobin correlated in the normal (r = 0.60, p less than 0.01) but not in the diabetic group (r = 0.02, NS). Birth weight ratio was higher in infants of diabetic than of normal mothers (1.10 +/- 0.16 versus 0.99 +/- 0.13, p less than 0.05) but failed to correlate with cord or maternal glycosylated haemoglobin or, in the diabetic group, with mean blood glucose.