Which role for adrenomedullin in human parturition?

Adrenomedullin is a vasorelaxant peptide which possesses also inhibitory ef fects on the contractile response of rat uterine muscle to galanin. In orde r to investigate whether fete-placental adrenomedullin production is altere d before and after labour in humans, we studied 80 pregnant women grouped a ccording to gestational age and presence of labour. Maternal and fetal plas ma adrenomedullin levels did not differ between groups, while amniotic flui d concentrations were higher in preterm labour. In 8 women at term followed longitudinally, plasma adrenomedullin concentration incresed with the onse t of labour and decreased as cervical dilatation progressed being 173.2 pg/ ml at the beginning of the active stage of labour and 57.3 pg/ml at the tim e of delivery. These results suggest that a decrease in adrenomedullin prod uction is not involved in the onset of labour in human, but rather that it may play a role other than myometrial relaxation in human parturition.