Longitudinal data for intrauterine levels of fetal IGF-I and IGF-II.
OBJECTIVE
An increasing body of evidence supports a major role for the insulin-like growth factors (IGFs) in the control of human fetal growth. Individual data at various times of pregnancy suggest that IGF-I and IGF-II levels remain stable up to the 33rd week of pregnancy. Thereafter, both increase to reach values 2-3 times higher at term. In order to provide an accurate reflection of fetal IGFs in utero, we sampled fetal blood from the umbilical cord by cordocentesis.


METHODS
We measured IGF-I and IGF-II in 12 fetuses longitudinally for up to 5 times between the 21st week of gestation and delivery.


RESULTS
All patients showed a progressive increase in IGF-I and IGF-II levels. Data determined during different time intervals (before 29th, 29th to 32nd, after 32nd week) were compared and the main increase was found after the 32nd week. The median for IGF-I before the 29th week was 33.5 ng/ml (range 19-40.5) and increased to 41 ng/ml (32-59) between the 29th to 32nd and further to 54.1 ng/ml (range 17-70) thereafter. During the same time interval, the median for IGF-II increased from 217 ng/ml (86-326) to 349 ng/ml (227-467). In 7 patients, cord blood after delivery was available. For IGF-II a further increase was consistently found after birth (from 282 ng/ml (175-511) to 393 ng/ml (297-513)), whereas only 2 fetuses showed an increase in IGF-I.


CONCLUSIONS
We conclude that in human fetuses, IGF-I and IGF-II levels increase longitudinally throughout pregnancy. Therefore, they may become important markers of healthy fetal development.
Gohlke
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BC
Department of Paediatrics, University of Bonn, Adenauerallee 119, DE-53113 Bonn, Germany. Gohlke-Bonn@t-online.de
Fahnenstich
H
H
Dame
C
C
Albers
N
N
D017218:Cordocentesis; D005314:Embryonic and Fetal Development; D005260:Female; D005312:Fetal Blood / Q000378:metabolism*; D005865:Gestational Age; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D007335:Insulin-Like Growth Factor II / Q000378:metabolism*; D008137:Longitudinal Studies
D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II