C-peptide and insulin levels at 24-30 weeks' gestation: An increased risk of adverse pregnancy outcomes?

Objective: The hypothesis was that fasting C-peptide and insulin values, during an oral glucose tolerance test (OGTT), might allow an estimation of the increased risk for gestational hypertension (GH) and fetal macrosomia. Study design: Two-hundred and six consecutive patients were submitted to an OGTT. Thirty-five developed gestational hypertension and 29 delivered large-for-gestational-age (LGA) newborns. Plasma glucose levels (mg/dl) and insulin levels (μU/ml) were measured fasting and after 60, 120 and 180min C-peptide fasting levels (ng/ml) were also measured. Results: Twenty-five patients were excluded, 181 were enrolled. According to the OGTT, 143 patients were classified as normal, 26 were found affected by gestational diabetes (GD) mellitus, and 12 had impaired gestational glucose tolerance (IGGT). Hypertensive women exhibited higher 60 and 120min insulin values than the normotensive group (128.3±69.9μU/ml versus 86.2±58.3μU/ml, P<0.05; 104.9±66.4μU/ml versus 78.7±56.5μU/ml, P<0.05).C-peptide cut-off at 2.9ng/ml resulted predictive for patients delivering large-for-gestational-age newborns (OR=3.42, 95% CI=1.59-7.39). Conclusions: C-peptide and insulin may be used as indicators of risk for the development of complications in late pregnancy. Copyright © 2002 Elsevier Science Ireland Ltd.