The effects of labor on maternal and fetal levels of insulin-like growth factor binding protein-1

OBJECTIVE: Our purpose was to determine the effects of labor and fetal hypoxia on the levels of insulin-like growth factor binding protein-1 in the maternal and fetal circulation. STUDY DESIGN: Serum levels of insulin-like growth factor binding protein-1 were determined in maternal and umbilical blood at delivery in two groups. The first group included 43 vaginal deliveries and 23 elective cesarean sections. The second group consisted of 44 women; in 24 the liquor was meconium stained and in 20 it was clear. RESULTS: Levels of insulin-like growth factor binding protein-1 in the neonate were lower in deliveries occurring before onset of labor (p < 0.001), Mann-Whitney U test) and higher in cases with severe meconium staining (p = 0.01). There were no differences in maternal levels of insulin-like growth factor binding protein-1 between subjects in labor and not in labor or those with or without meconium staining. CONCLUSION: The process of labor leads to an increase in fetal levels of insulin-like growth factor binding protein-1. This increase may well be associated with the relative fetal stress that occurs during labor. This suggestion is supported by the finding of the highest levels in labors in which there was thick staining of the liquor.