Serum insulin, insulin-like growth factor-I, and insulin-like growth factor binding protein-1 in women who develop preeclampsia

OBJECTIVE: To determine whether second-trimester serum concentrations of insulin, insulin-like growth factor-I (IGF-I), and insulin-like growth factor binding protein-1 (IGFBP-1) were altered in women before they developed clinical signs of preeclampsia. METHODS: A nested case-control study used serum obtained during second-trimester pregnancies from 12 women who developed preeclampsia matched with 24 controls who remained normotensive. Nine preeclamptic subjects and 18 controls were necessary to have 80% power to discern a 20% difference between groups with regard to the analytes under consideration. RESULTS: There were no significant differences between cases and controls with respect to many demographic factors. Women who developed preeclampsia had insulin concentrations that were not significantly different from controls, but serum concentrations of IGF-I were significantly higher and IGFBP-1 were significantly lower than those of the controls. The IGF-I/IGFBP-1 ratio helped to identify those at risk for developing preeclampsia. CONCLUSIONS: Serum concentrations of IGF-I and IGFBP-1 were abnormal long before women manifested clinical evidence of preeclampsia in this study. These alterations might be related to abnormalities in trophoblastic invasion and prove useful as potential markers for the identification of women who are at high risk of developing preeclampsia.