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.

Other side effects include nausea, vomiting, diarrhea, and diaphoresis. Finally, some serious but luckily rare side effects include cardiac arrhythmias, disseminated intravascular coagulation, and amniotic fluid embolism.

Prostaglandins are contraindicated when there’s a pelvic infection or sepsis, as well as the presence of fetal cephalopelvic disproportion, unfavorable fetal position, placenta previa, and any other obstetric emergencies that could require surgical intervention.

They are also contraindicated if there’s a history of cesarean birth or other uterine surgery because of the risk of uterine rupture.

Prostaglandins should also be avoided in those with grand multiparity, meaning they’ve given birth 5 or more times.

Finally, prostaglandins must be used with caution in clients with asthma, glaucoma, or hepatic, renal, respiratory, or cardiovascular disease, since they can exacerbate these conditions.

Now, before administering prostaglandins for cervical ripening, ensure there are no contraindications or preexisting conditions to receiving prostaglandins.

Then, verify that the obstetrician or midwife has provided information to the client about the medication and how it is used. Reinforce information regarding the benefits and risks of cervical ripening as needed.

Next, identify the fetal lie and presentation to ensure there’s a favorable fetal position for induction, assess the status of the cervix, assess uterine activity and obtain a baseline fetal heart rate or FHR.

Registered nurses with additional training and demonstrated competence can safely administer dinoprostone for cervical ripening.