Prostaglandins in dysfunctional labour; evidence for altered production of prostaglandin F2 alpha.

Dysfunctional labour was studied in relation to prostaglandin concentrations in amniotic fluid and production by fetal membranes. Initial clinical validation of the model established the presence of hypokinetic labour with no evidence of obstruction to the fetal progress. Prostaglandin F2 alpha (PGF2 alpha) and 13, 14 dihydro-15-keto-prostaglandin-F2 alpha concentrations in the amniotic fluid were low despite relatively normal concentrations of prostaglandin E2. Membranes removed from patients with the condition released very low concentrations of PGF2 alpha from the amniotic side with no alteration on the choriodecidual side of the membrane. Studies of free and phospholipid-associated arachidonic acid indicated normal release of arachidonic acid in dysfunctional labour. No changes in amniotic fluid-related inhibitors and stimulators of prostaglandin synthetase were detected. It is suggested that PGF2 alpha production is impaired in dysfunctional labour and that this prostaglandin is primarily involved in the progress of labour.