IGF1 and fetal growth restriction: In addition, previous studies in our laboratory have found that prenatal exposure to nicotine, ethanol, or caffeine can activate the maternal HPA axis and bypass the placental GC barrier, resulting in fetal exposure to abnormal maternal GC levels and a changed glucocorticoid-insulin-like growth factor 1 (GC-IGF1) axis that eventually leads to IUGR occurrence, multi-organ development programming alterations, and susceptibility to multiple adult diseases [24,25,26].