Hyperglycemia associated with adverse pregnancy outcomes

Maternal glucose levels below those diagnostic of diabetes were linked to increased birth weight and increased cord-blood serum C-peptide levels, according to results of a recent study.

Researchers from Northwestern University Feinberg School of Medicine, Endocrinology, Chicago, and other national and international sites conducted a study of pregnant women (n=25,505) at 15 centers in nine countries. The women were given 75g oral glucose tolerance tests at 24 to 32 weeks of gestation.

Adjusted odds ratios for adverse pregnancy outcomes associated with an increase in the fasting glucose level of one SD (6.9 mg/dL), the 1-hour fasting glucose level of one SD (30.9 mg/dL) and the 2-hour fasting glucose level of one SD (23.5 mg/dL) were calculated for the participants with blinded data (n=23,316), according to the study.

The odds ratios were 1.38 (95% CI, 1.32-1.44), 1.46 (95% CI, 1.39-1.53) and 1.38 (95% CI, 1.32-1.44) for birth weight .90th percentile. The odds ratios were 1.55 (95% CI, 1.47-1.64), 1.46 (95% CI, 1.38-1.54) and 1.37 (95% CI, 1.30-1.44) for cord-blood serum C-peptide levels .90th percentile.

For primary cesarean delivery, odds ratios were 1.11(95% CI, 1.06-1.15), 1.10 (95% CI, 1.06-1.15) and 1.08 (95% CI, 1.03-1.12), according to the study. For neonatal hypoglycemia, odds ratios were 1.08 (95% CI, 0.98-1.19), 1.13 (95% CI, 1.03-1.26) and 1.10 (95% CI, 1.00-1.12). – by Christen Haigh

N Engl J Med. 2008;358:1991-2002.

It has been recognized for several decades that diabetes is associated with adverse pregnancy outcomes. It is now becoming apparent that there is no clear "cut off" value defining glucose intolerance. As glucose levels increase, the risks to mother and baby increase as well.

– Robert W. Rebar, MD

Endocrine Today Editorial Board member