INS and gestational diabetes: Given that circulating free (35) as well as total (36) IGF-I appears to influence insulin sensitivity, we hypothesized that the strong associations observed with GDM, high blood pressures, and insulin sensitivity are underpinned by PAPP-A regulating IGF bioavailability in pregnancy, which in turn regulates insulin sensitivity and ultimately contributes to protection against, or the development of, certain adverse conditions of pregnancy.