Evaluation of folate concentration in amniotic fluid and maternal and umbilical cord blood during labor

Folate is required for fetal, placental and maternal tissue growth during pregnancy. A decline in maternal circulating folate concentrations and an increase in total homocysteine (a non-specific indicator of folate deficiency) have been observed with the progression of pregnancy. However, the role of folate in the third trimester of pregnancy is not clear and folate status in late pregnancy has not so far been widely analyzed. The main aim of this retrospective cross-sectional study was to determine the folate concentrations in amniotic fluid and in maternal and umbilical cord blood serum derived during delivery.

This study was conducted on 175 pregnant Polish women (white/Caucasian) aged between 17 and 42 years. Only pregnancies without birth defects were included in this study. Amniotic fluid, maternal serum, and umbilical cord blood samples were collected during vaginal delivery or cesarean section. Folate concentration was determined using a microbiological assay.

Strong correlations were observed between the concentrations of folate in amniotic fluid and maternal serum (rho = 0.67, p < 0.001) and amniotic fluid and cord blood serum (rho = 0.49, p < 0.001) and between maternal serum and cord blood serum (rho = 0.67, p < 0.001). Folate concentrations in amniotic fluid were significantly associated with maternal age (rho = 0.19, p < 0.05). Pre-pregnancy body mass index and maternal weight/neonatal birth weight ratio were independent predictors of folate concentrations in maternal serum (β = 0.33, p < 0.05; β = -0.19, p < 0.05) and amniotic fluid (β = 0.28, p < 0.05; β = -0.19, p < 0.05) in late pregnancy.

Folate concentrations in amniotic fluid are associated with maternal and neonatal folate status peripartum in healthy women.