[A study on the relationship between insulin-like growth factor, insulin-like growth factor-binding protein-3 and fetal growth retardation].

OBJECTIVE: To explore the effect of insulin-like growth factor-I (IGF-I), insulin-like growth factor-II (IGF-II) and insulin-like growth factor-binding protein-3 (IGFBP-3) on the fetal growth. METHODS: Samples of maternal blood and matched umbilical cord blood were collected at time of delivery from twenty pairs of mothers and newborns with normal birth weight (control group) twenty pairs with fetal growth restriction (FGR group) and ten pairs with macrosomia (macrosomia group). Serum IGF-I, IGF-II and IGFBP-3 were measured by radioimmunoassay (RIA) and immunoradiometric analysis (IRMA). RESULTS: (1) Levels of maternal serum IGF-I, IGF-II and IGFBP-3 in GFR group were (130.5 +/- 26.0) microgram/L, (2.40 +/- 0.42) microgram/L, (5 579 +/- 848) microgram/L respectively; IGF-I, IGF-II and IGFBP-3 levels of fetal serum in this group were (6.6 +/- 1.7) microgram/L, (1.54 +/- 0.31) microgram/L, (869 +/- 183) microgram/L respectively. (2) In macrosomia group the levels of maternal serum IGF-I, IGF-II and IGFBP-3 were (309.7 +/- 44.6) microgram/L, (2.43 +/- 0.25) microgram/L, (5 562 +/- 742) microgram/L respectively. In fetal serum that were (69.6 +/- 23.9) microgram/L, (2.19 +/- 0.29) microgram/L, (1 682 +/- 130) microgram/L respectively. (3) In control group the levels of maternal serum IGF-I, IGF-II and IGFBP-3 were (307.9 +/- 70.7) microgram/L, (2.41 +/- 0.36) microgram/L, (5 586 +/- 678) microgram/L respectively;That were (68.9 +/- 32.9) microgram/L, (1.95 +/- 0.26) microgram/L, (1 624 +/- 296) microgram/L in fetal serum respectively. (4) In three group the levels of maternal IGF-I, IGF-II and IGFBP-3 were significantly higher than that of fetal levels (P < 0.01). The fetal IGF-I, IGF-II and IGFBP-3 levels in FGR group were significantly lower than those in control group (P < 0.01). (5) The levels of fetal IGF-I, IGF-II, IGFBP-3 were positively correlated with birth weight (r = 0.61, r = 0.51 and 0.63, P < 0.01) and placental weight (r = 0.47, r = 0.56 and 0.48, P < 0.01). The levels of fetal IGF-I, IGF-II and IGFBP-3 were no different between macrosomia group and control group. CONCLUSIONS: This study suggest that (1) IGF-I, IGF-II and IGFBP-3 cannot pass through the placenta. (2) The betal IGF-I, IGF-II and IGFBP-3 may have the close relationship with the fetal growth. The decrease of IGF-I, IGF-II and IGFBP-3 may be one of the causes of FGR.