Meconium and Amniotic Fluid IgG Fc Binding Protein (FcGBP) Concentrations in Neonates Delivered by Cesarean Section and by Vaginal Birth in the Third Trimester of Pregnancy.

IgG Fc binding protein (FcGBP) is a mucin-like protein that binds strongly to IgG and IgG-antigen complexes in intestinal mucus. FcGBP presence and its altered expression levels in meconium accumulating in the fetal intestine and amniotic fluid flowing in the intestine may provide new knowledge of the mechanisms responsible for the immune adaptation of the fetus to extrauterine life. FcGBP concentrations were measured by ELISA in the first-pass meconium and amniotic fluid samples collected from 120 healthy neonates delivered by either vaginal birth ( = 35) or cesarean section ( = 85) at 36 to 41 weeks gestation. The meconium FcGBP concentrations (405.78 ± 145.22 ng/g) decreased (r = -0.241, = 0.007) over the course of 36 to 41 weeks gestation, but there were no significant changes ( > 0.05) in the amniotic fluid FcGBP (135.70 ± 35.83 ng/mL) in the same period. Both meconium and amniotic fluid FcGBP concentrations were higher ( < 0.05) in neonates delivered by cesarean section. Decreases in the meconium FcGBP concentrations correlated (r = -0.37, = 0.027) with the gestational age in neonates delivered by vaginal birth but not in those delivered by cesarean section ( > 0.05). No association was found between the FcGBP concentrations in meconium and amniotic fluid and the birth weight ( > 0.05). With the development of the mucosal immune system in the fetal intestine over the course of the third trimester of gestation, the meconium FcGBP concentrations decrease. Increased FcGBP concentrations measured in the meconium and amniotic fluid of neonates delivered by cesarean section may possibly indicate altered intestinal mucosal function. Intrauterine growth is not associated with the intestinal mucosal barrier maturation involving FcGBP.