Maternal postprandial blood glucose levels influence infant birth weight in diabetic pregnancy.

Relationships between maternal glycaemia and neonatal birth weight were studied prospectively in 14 tightly controlled pregnant women with pre-existing type 1 diabetes mellitus. Maternal glycaemia throughout pregnancy was determined from daily self blood glucose (BG) monitoring with memory meters and fortnightly fructosamine (Fr) and glycated haemoglobin (HbA1) measurements. Mean non-fasting BG and mean HbA1 throughout pregnancy correlated strongly (Spearman rank) with birth weight (0.64 and 0.73 respectively), as did mean second trimester non fasting BG (0.54), HbA1 (0.7) and Fr (0.64) and mean third trimester HbA1 (0.65), whereas mean fasting BG showed no significant correlations with birth weight at any age of pregnancy. The disparity between the strong correlation of non fasting BG with birth weight and the poor correlation of fasting BG suggests that postprandial as opposed to basal glycaemia significantly influences foetal growth and neonatal size.