Insulin-like growth factor-binding protein-1 in umbilical artery and vein of term fetuses with signs suggestive of distress during labor.
Insulin-like growth factor-binding protein-1 (IGFBP-1) is believed to be an inhibitory factor for fetal growth. The regulation of IGFBP-1 secretion in the fetus is uncertain, although insulin and oxygen tension (PO2) and saturation are thought to play a role. We studied IGFBP-1 levels in umbilical cord artery (UA) and vein (UV) of 98 singleton fetuses at term with clinical signs of distress during labor, i.e. meconium-stained liquor or/and an abnormal fetal heart rate tracing. Blood gas values and serum C-peptide and IGFBP-1 concentrations were measured in both UA and UV. Twenty-five fetuses had an UA pH<7.20. The concentrations of IGFBP-1 were similar in UA and UV and were highly correlated (r=0.98). IGFBP-1 levels were inversely correlated with birth weight, with increased concentrations in small-for-gestational age fetuses (< or =10th weight percentile). IGFBP-1 levels were negatively correlated with C-peptide concentrations, and remained so after correction for birth weight (r=-0.37 for both UA and UV; P<0.001); more specifically, IGFBP-1 levels were increased in the lowest C-peptide quartile (<0.23 nmol/l) compared with the other quartiles. In addition, IGFBP-1 levels were inversely correlated with PO(2) values (r=-0.39 in UA and r=-0.34 in UV; P<0.001); quartiles of UA and UV PO2 showed a gradual increase in IGFBP-1 concentrations with lower PO2 values. A regression model with C-peptide and PO2 values as independent variables predicted IGFBP-1 concentrations (R2 of model was 0.25 and 0.22 for UA and UV respectively; P<0.001). Other blood gas values (pH, PCO2, HCO3- and base deficit) did not correlate with IGFBP-1 levels. The data of this study indicate that serum IGFBP-1 levels in term fetuses are determined by both insulin and PO2 levels, and suggest that acute hypoxemia stimulates IGFBP-1 secretion in the fetus.
Verhaeghe
J
J
Department of Obstetrics and Gynaecology, and Laboratorium voor Experimentele Geneeskunde en Endocrinologie, Katholieke Universiteit Leuven, Leuven, Belgium. johan.verhaeghe@uz.kuleuven.ac.be
Billen
J
J
Giudice
L C
LC
D000704:Analysis of Variance; D001724:Birth Weight; D002096:C-Peptide / Q000378:metabolism; D005260:Female; D005316:Fetal Distress / Q000097:blood*; D006801:Humans; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000097:blood*; D007744:Obstetric Labor Complications / Q000097:blood*; D010100:Oxygen / Q000097:blood; D010313:Partial Pressure; D011247:Pregnancy; D014469:Umbilical Arteries / Q000378:metabolism*; D014471:Umbilical Veins / Q000378:metabolism*
D002096:C-Peptide; D018970:Insulin-Like Growth Factor Binding Protein 1; D010100:Oxygen