Galanin concentrations in maternal circulation, amniotic fluid and umbilical cord blood during term labor: relationship with maternal body mass and neonatal birth weight.

BACKGROUND: Galanin is a hypothalamic regulatory peptide involved in the regulation of appetite. It is synthesized by the nervous system, anterior pituitary gland, adrenal medulla, pancreas, intestine and placenta. Placental secretion of galanin has until now only been investigated in animals. Additionally, galanin concentration has not been assessed in umbilical cord blood and amniotic fluid.

PATIENTS AND METHODS: Galanin concentrations were measured in maternal circulation before term delivery, in cord blood and in amniotic fluid of 45 healthy pregnant women (gestational age 38 - 40 gestational weeks). The control group consisted of 26 normally menstruating healthy women.

RESULTS: Plasma galanin concentrations were found to be similar in pregnant healthy women before term delivery (20.8 +/- 1.9 pg/ml) and non-pregnant women (19.0 +/- 1.7 pg/ml). Galanin concentration in umbilical cord blood (26.5 +/- 2.2 pg/ml) was significantly higher (p < 0.05) than in maternal circulation. Galanin concentration in amniotic fluid (20.4 +/- 1.0 pg/ml) was similar to that observed in maternal plasma, but significantly (p < 0.01) lower than in umbilical cord blood. A significant correlation was found between maternal body mass index and plasma galanin concentration (tau = 0.246; p < 0.05) and between birth weight and cord blood galanin concentration (tau = 0.345; p = 0.01). There was no significant correlation between placental mass and cord blood galanin concentration (tau = 0.124; p = 0.26).

CONCLUSIONS: Plasma galanin concentration in pregnant women before term delivery is similar to that in non-pregnant women. The fetus rather than the placenta is the source of the high galanin concentration in umbilical cord blood. The role of galanin in the regulation of newborn weight is uncertain.