Maternal insulin-like growth factors and insulin-like growth factor-binding proteins for macrosomia prediction in diabetic and nondiabetic pregnancy: A prospective study.

Objective: Attributable to the insulin-like growth factor (IGF) axis involvement in fetal growth regulation, possible contribution of the maternal IGF axis to antenatal fetal macrosomia diagnosis is a subject of particular interest in diabetic pregnancy.

Methods: A total of 130 women were prospectively enrolled in a longitudinal single-center cohort study. The four study groups were: type 1 diabetes (n = 40), type 2 diabetes (n = 35), gestational diabetes (n = 40), and control (n = 15). IGF-1 and IGF-2 and insulin-like growth factor-binding protein (IGFBP) 1, 3, 6, and 7 serum levels were analyzed in 11- to 14-week and 30- to 34-week samples with a specific immunoassay.

Results: In mothers of large-for-gestational-age neonates (90th percentile), higher (median test) first-trimester IGF-1 (P = 0.007) and lower IGFBP-1 (P = 0.035) were observed. The IGF-1/IGFBP-1 ratio was positively associated with neonatal weight (r = 0.434, P < 0.001). Receiver operating characteristic analysis revealed an association between large for gestational age and the first-trimester IGF-1 (area under the curve [AUC] = 0.747, P < 0.001), IGFBP-1 (AUC = 0.334, P = 0.011), and IGF-1/IGFBP-1 ratio (AUC = 0.750, P < 0.001). IGF-1/IGFBP-1 ratio had better performance for prediction of birth weight over 4000 g (AUC = 0.822, P < 0.001).

Conclusion: The authors detected different first-trimester IGF-1 and IGF-1/IGFBP-1 thresholds applicable for either supposition or rejection of macrosomia diagnosis. Further investigation is needed to determine how the maternal IGF axis can contribute to fetal macrosomia prediction.