Human decidua and uterine contractility

Physiological saline solution injected into the uterus by the extraamniotic route was found to damage the decidua and rupture its lysosomes. The mechanism by which this procedure provokes abortion may be through the release of lysosomal phospholipase A2 (EC 3.1.1.4), an enzyme thought to regulate the formation of polyunsaturated fatty acids utilized for prostaglandin synthesis. A similar sequence of events may be involved in the initiation of spontaneous labour, since decidual cells obtained at elective Caesarean section at term exhibited degenerative changes and signs of release of a lysosomal marker enzyme. The cause of this release is unknown.