title: Fetal serum levels of insulin, growth hormone and insulin-like growth factor-I in concordant and discordant twin gestations.
abstract: OBJECTIVE
  To examine the role of insulin, growth hormone and insulin-like growth factor (IGF)-I in concordant and discordant twin pairs.
  
  
  METHODS
  Umbilical cord serum samples were obtained from 20 twin pairs with weight discordancy (intertwin birth weight difference > 20%) and from 20 concordant twins (intertwin birth weight difference < 20%), both groups of similar gestational age, gravidity, and parity. The serum samples were analyzed for the levels of IGF-I, growth hormone and insulin in both maternal and fetal compartments.
  
  
  RESULTS
  Among the group of discordant twins, the normally grown twin, in all cases, had significantly higher cord serum IGF-I levels than their growth-restricted co-twin (108 +/- 73 ng/ml vs. 39 +/- 24 ng/ml; p < 0.01). There were no significant intertwin differences in the cord blood IGF-I levels in the concordant twin pairs (87 +/- 44 vs. 88 +/- 48 ng/ml; p = 0.986). Insulin and growth hormone levels did not correlate with intertwin birth weight differences.
  
  
  CONCLUSIONS
  These data demonstrate that IGF-I is important in the regulation of both normal and restricted fetal growth in utero, and its action appears to be, at least in part, through an endocrine action. The precise role of growth hormone and insulin in fetal growth restriction remains uncertain.
authors.affiliation: Department of Obstetrics and Gynecology and Reproductive Sciences, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA.
authors.forename: A
authors.initials: A
authors.lastname: Wiznitzer
authors.forename: E A
authors.initials: EA
authors.lastname: Reece
authors.forename: B
authors.initials: B
authors.lastname: Furman
authors.forename: C
authors.initials: C
authors.lastname: Homko
authors.forename: R
authors.initials: R
authors.lastname: Gakma
authors.forename: M
authors.initials: M
authors.lastname: Mazor
authors.forename: J
authors.initials: J
authors.lastname: Levy
mesh_terms: D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D005317:Fetal Growth Retardation / Q000097:blood; D020567:Fetal Weight; D019382:Human Growth Hormone / Q000097:blood*; D006801:Humans; D007328:Insulin / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000032:analysis* / Q000502:physiology; D011247:Pregnancy; D014427:Twins
chemical_list: D007328:Insulin; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I