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

Abstract 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.