Mechanism for increased production of prostaglandins in labour.

It is proposed that uterine hypoxia, beginning initially with the uterine contractions in late pregnancy, leads to the increased formation of free fatty acids. The liberated fatty acids are then used to form prostaglandins and they can also act on mitochondria to release calcium. The released calcium can directly activate contractile proteins and/or can further stimulate phospholipase A (active at neutral pH) and thereby reinforce the progressive production of prostaglandins.