Fetal and maternal plasma insulin-like growth factors and binding proteins in pregnancies with appropriate or retarded fetal growth.
A prospective observational study of 104 women was performed to study whether the insulin-like growth factor (IGF) system in pregnancy before labour is associated with reduced fetal growth. Fetal blood was obtained by cordocentesis for prenatal diagnosis or at elective caesarean delivery and a maternal sample was also obtained, IGF-1 and IGF-2 and their binding proteins -1 and -3 were measured by RIA. The 35 case were smaller than -2S.D.s by ultrasound abdominal circumference and birthweight and were subdivided into fetal growth retardation (FGR, n = 20) and small for gestational age (SGA, n = 15) by Doppler velocimetry and neonatal outcome. Controls (n = 69) were normally grown. Control maternal IGF-1 (r = 0.65, P < 0.0001) and IGFBP-3 (r = 0.46, P = 0.001) increased with advancing gestational age. In FGR cases, maternal IGF-1 was low (P = 0.0001) and IGFBP-1 was high (P = 0.03) and maternal IGF-2 was low in SGA (P = 0.005). In the SGA fetus, IGF-2 was low (P = 0.0009) and IGFBP-3 (P = 0.02) was high. In FGR, IGFBP-1 (P < 0.0001) and IGFBP-3 (P = 0.002) were both elevated. These data do not support the hypothesis that fetal IGF-1 deficiency is a common cause of FGR. Elevated binding proteins may lead to a relative deficiency of free IGF but changes in binding proteins may be secondary to metabolic changes. In FGR, maternal IGF-1 was low with high binding proteins, so this system may be important in controlling placental transfer.
Holmes
R
R
Fetal Medicine Research Unit, St. Michael's Hospital, Bristol, UK.
Montemagno
R
R
Jones
J
J
Preece
M
M
Rodeck
C
C
Soothill
P
P
D005314:Embryonic and Fetal Development / Q000502:physiology; D005260:Female; D005312:Fetal Blood / Q000378:metabolism*; D005317:Fetal Growth Retardation / Q000097:blood* / Q000000981:diagnostic imaging; D006801:Humans; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000097:blood*; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D007335:Insulin-Like Growth Factor II / Q000378:metabolism*; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D011863:Radioimmunoassay; D016216:Ultrasonography, Prenatal
D018970:Insulin-Like Growth Factor Binding Protein 1; D018972:Insulin-Like Growth Factor Binding Protein 3; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II