Relationship of insulin-like growth factor-I, insulin-like growth factor binding protein-3, insulin, growth hormone in cord blood and maternal factors with birth height and birthweight.
BACKGROUND
To determine whether the following factors are related to birthweight or birth height, we measured insulin-like growth factor (IGF)-I, insulin-like growth factor binding protein (IGFBP)-3, insulin and growth hormone (GH) levels in cord blood and also observed the relationship between birthweight, birth height and maternal factors.


METHODS
One hundred and ninety-four cord bloods were collected, 106 from males and 88 from females. Three newborns were small for gestational age (SGA), 168 were appropriate (AGA) and 23 were large (LGA); 21 newborns were preterm and 172 were term.


RESULTS
Levels of IGF-I and IGFBP-3, measured by enzyme-linked immunosorbent assay, were significantly lower in preterm babies (35.3 +/- 15.1 and 1025.6 +/- 562.8 ng/mL, respectively) than in term babies (61.6 +/- 39.5 and 1252.6 +/- 403.2 ng/mL, respectively; P < 0.01), but neither insulin nor GH levels, measured by radioimmunoassay, showed any significant difference between the two groups (P > 0.05). Among term babies, IGF-I and IGFBP-3 levels were significantly higher in the LGA group (96.1 +/- 34.1 and 1544.7 +/- 418.1 ng/mL, respectively) than in the AGA group (56.4 +/- 37.6 and 1212.8 +/- 383.4 ng/mL, respectively; P < 0.01). Levels of IGF-I and IGFBP-3 showed significant correlation with birthweight and length, respectively (P < 0.01), although GH and insulin levels did not (P > 0.05). There was a significant correlation between IGF-I and IGFBP-3 levels (P < 0.01, r = 0.64), but IGF-I and IGFBP-3 levels showed no relationship with GH or insulin levels. Birthweight correlated significantly with prepartum maternal weight, maternal weight gain and maternal height (P < 0.05), but birth length correlated significantly only with maternal height (P < 0.05).


CONCLUSIONS
Our results suggest that fetal growth depends on fetal levels of IGF-I and IGFBP-3 and maternal factors, not on insulin or GH. Levels of IGF-I and IGFBP-3 may not be regulated by insulin alone, but by the complex interactions between several factors, such as insulin, GH and maternal factors.
Yang
S W
SW
Department of Pediatrics, Seoul National University College of Medicine, Korea. growth@plaza.snu.ac.kr
Yu
J S
JS
D001724:Birth Weight / Q000502:physiology; D001827:Body Height / Q000502:physiology; D005314:Embryonic and Fetal Development / Q000502:physiology*; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D019382:Human Growth Hormone / Q000097:blood; D006801:Humans; D007328:Insulin / Q000097:blood; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D008297:Male
D007328:Insulin; D018972:Insulin-Like Growth Factor Binding Protein 3; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I