Prostaglandins: Nursing pharmacology

Prostaglandins are a group of molecules released by most cells in the body that can have effects on different tissues and organs, including the uterus, where they cause cervical ripening and uterine muscle contraction.

Prostaglandins include dinoprostone, also referred to as PGE2, and misoprostol, also referred to as PGE1. Dinoprostone is a naturally occurring prostaglandin E2 that comes in the form of a gel for endocervical administration, or vaginal insert administered intravaginally.

Dinoprostone is typically used to facilitate labor by inducing cervical ripening, to induce abortion in the second trimester, or to evacuate the uterus when there’s a spontaneous abortion or intrauterine fetal death, as well as to manage a benign hydatiform mole.

Misoprostol, on the other hand, is a synthetic prostaglandin E1 analog that can be administered intravaginally and sometimes orally for cervical ripening.

It is also used to control postpartum hemorrhage, for treatment of incomplete or missed abortion, and to induce abortion when administerd with mifeprostone, a progestrone agonist.

Once administered, prostaglandins stimulate secretion of collagenase in the cervix, which degrade collagen.

This increases the relative amount of water, which softens the cervix which facilitates cervical ripening. It also triggers an increase of intracellular calcium, which causes the smooth muscle cells in the uterus to contract with increased strength, frequency and duration.

The main side effects of prostaglandins are related to uterine hyperstimulation, where there’s too much contraction.

This could cause painful contractions, and lead to uterine rupture and hemorrhage. It could even restrict placental blood flow, resulting in abnormal fetal heart rate patterns.