GROWTH-FACTORS AND INTRAUTERINE GROWTH-RETARDATION .1. SERUM GROWTH-HORMONE, INSULIN-LIKE GROWTH-FACTOR (IGF)-I, IGF-II, AND IGF BINDING-PROTEIN 3 LEVELS IN NORMALLY GROWN AND GROWTH-RETARDED HUMAN FETUSES DURING THE 2ND HALF OF GESTATION

The aim of this study was to relate human fetal growth retardation to specific hormone alterations. Serum levels of GH, IGF-I, IGF-II, and I GF binding protein (BP) 3 were measured during the second half of gest ation after cordocentesis in 230 fetuses who were classified into norm ally grown (n = 166) and growth-retarded (it = 64) groups according to ante- and neonatal measurements. The normally grown group showed a pr ogressive decline in serum GH levels toward term (r = -0.42, p = 0.000 1), whereas serum IGF-I was increased (r = 0.55, p = 0.0001), as were serum IGF-II (r = 0.21, p = 0.008) and IGFBP3 levels (r = 0.19, p = 0. 02), although less markedly. For all hormone levels, wide individual d ifferences were found at any given age of gestation. The incidental pr esence of fetal malformations in either the normally grown group (n = 101 cases) or the growth-retarded group (it = 50 cases) had no apparen t effect on these hormone levels as compared with members of the group s showing no fetal malformations (it = 73 cases). Comparison of the no rmally grown group with the growth-retarded group showed that serum GF -I levels were significantly lower in the growth-retarded group (p = 0 .001). No differences were found between the groups in serum GH, IGF-I I, and IGFBP3 levels, although if data for the third trimester were ta ken alone, serum IGF-II levels were found to be lower in the growth-re tarded group (p = 0.05). In conclusion, during the second half of gest ation, fetal serum IGF-I levels may be influenced by nutritional facto rs controlling fetal growth. However, the wide individual differences in measurements make it a very poor biologic marker of intrauterine gr owth retardation.