Prostaglandins in pregnancy

Prostaglandins in pregnancy

Prostaglandins E and F series are used to increase uterine contractility. They promote a series of coordinated contractions in the uterus. In early to middle pregnancy oxytocin cannot cause significant uterine contractility due to lack of sensitivity of myometrial membrane to oxytocin at this stage. In contrast, the uterus is sensitive to prostaglandins at this time.

The prostaglandin analogues dinoprostone (PGE2analogue), carboprost

(PGF analogue), and misoprostol(PGE1 analogue) belong to this group of drugs. Their mechanism of action is poorly understood. They probably act together with oxytocin in order to augment release of Ca2+, thereby increasing uterine contraction. Adverse effects of prostaglandin analogues are nausea, vomiting, diarrhea, and dose-dependent fever. More serious adverse effects include lung oedema and myocard infarction due to coronary spasms during prostaglandin E2 therapy. Misoprostol (25 μg every 4 h) is a safe and effective manner of inducing labour and delivery for women with an immature cervix.

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I. In addition to causing uterine contractions, prostaglandines cause ripening of the cervix. II. Prostaglandines also cause vasodilation.