Serum IGF-I and IGFBP-3 levels in pregnant adolescents in an economically depressed community

RESUMO

The growth hormone (GH) insulin-like growth factor-I (IGF-I) axis is believed to play a role in growth during postnatal and fetal life and is regulated by nutrition. However, very few studies have examined the effects of malnutrition on the regulation of the GH/IGF-I axis in human pregnancy during adolescence. In this study we compared the serum IGF-I and IGFBP-3 levels in a group (n=62) of pregnant adolescents in their second trimester of pregnancy and living in a poor area in the city of Bogotá, with those of a group (n=36) of non-pregnant adolescents from the same area. As reference, a group (n=20) of non-pregnant adolescents from a middle-class district in the same city was utilized. It was observed that the non-pregnant adolescents from the poor area were all below the 3rd percentile and showed significantly (p<0.05) reduced height and weight in comparison with subjects from middle-class area, suggesting growth retardation in this group of subjects. Serum IGF-I and IGFBP-3 levels were significantly (p<0.0001) reduced, in comparison with subjects from the middle-class area, although there was no evidence of delay of puberty based on Tanner stage of sexual development and only subjects at Tanner 5 were included in this study. When the serum concentrations of IGF-I and IGFB-3 in the population of pregnant adolescents were investigated, no differences were found with those observed in the non-pregnant adolescents from the poor district, which means that pregnancy was not accompanied by the elevation in IGF-I levels observed in normal pregnancies. In conclusion, the low circulating IGF-I levels observed in pregnant adolescents could mirror abnormalities on the normal physiology of the GH/IGF-I axis, whose effects on fetal growth are not completely understood