Maternal and fetal insulin-like growth factors and their binding proteins in the second and third trimesters of human pregnancy

The insulin-like growth factors (IGFs) are mitogenic polypeptides whichcirculate bound to a series of at least six binding proteins (IGFBPs). Anincreasing body of evidence supports a major role for the IGF in thecontrol of human fetal growth although normal values in the human fetalcirculation have not been established. In order to provide an accuratereflection of fetal IGFs and IGFBPs in utero, we have sampled fetal blooddirect from the umbilical cord at 18-38 weeks of gestation using thetechnique of cordocentesis. We have measured IGF-I, IGF-II and IGFBP 1-3 in91 fetuses in order to establish concentrations for these parameters in thesecond and third trimesters of human pregnancy.