Insulin-like growth factors (IGF) 1 and 2 in human foetal plasma and relationship to gestational age and foetal size during midpregnancy.
IGF-1 and IGF-2 were measured by specific radioimmunoassay after acid-ethanol extraction of plasma obtained by foetoscopy from 20 normal foetuses aged 15-23 weeks. IGF-1 and IGF-2 levels were 36 +/- 11 and 162 +/- 55 ng/ml, respectively. In comparison, levels in cord blood were 84 +/- 58 and 264 +/- 176 ng/ml, respectively, and in adult plasma were 410 +/- 106 and 818 +/- 272 ng/ml. Both IGF-1 and IGF-2 were in the normal foetal range in a further three foetuses with anencephaly and two foetuses with spina bifida. No sex difference was observed. IGF-1 was positively correlated with foetal body weight (P less than 0.001), placenta weight (P less than 0.02) and with body length measured crown-rump (P less than 0.01) or crown-heel (P less than 0.02). No correlation between IGF-2 and body weight, length, placenta weight or gestational age was found. Both IGF-1 and IGF-2 are present in the human foetal circulation earlier in gestation than has previously been demonstrated, the levels being low throughout this period of gestation in comparison with adult plasma.
D000028:Abortion, Induced; D000328:Adult; D000757:Anencephaly / Q000097:blood; D003430:Cross-Sectional Studies; D005314:Embryonic and Fetal Development; D005260:Female; D005312:Fetal Blood / Q000032:analysis*; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007334:Insulin-Like Growth Factor I / Q000097:blood*; D007335:Insulin-Like Growth Factor II / Q000097:blood*; D008297:Male; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011863:Radioimmunoassay; D013002:Somatomedins / Q000097:blood*; D016136:Spina Bifida Occulta / Q000097:blood
D013002:Somatomedins; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II