Increase of the prostaglandin precursor, arachidonic acid, in amniotic fluid during spontaneous labour

Concentrations of free arachidonic acid have been measured by gas liquid chromatography in amniotic fluid obtained during spontaneous labour at term. Levels of arachidonic acid ranged from 0.14 to 2.9 microgram/ml and increased significantly (P less than 0.01) with advancing cervical dilatation. Concentrations of arachidonic acid showed no significant relation to concentrations of either prostaglandin F or 13,14-dihydro-15-keto-prostaglandin F. These findings are discussed with respect to the role of arachidonic acid in the control of prostaglandin biosynthesis during human parturition.