Which prostaglandin helps in cervical ripening?

Appeared in: RUHS, Jaipur, M.Sc Nursing Entrance Exam-2019

Explanation

Prostaglandin E2 (PGE2), known as Dinoprostone, is a principal agent used to prepare the cervix for labor.
Its primary mechanism involves softening the cervix by breaking down collagen and increasing its water content, which leads to effacement and dilation.
PGE2 is commercially available in formulations like vaginal gels (Prepidil) and inserts (Cervidil), which are specifically approved for cervical ripening.

Option A: Although Prostaglandin E1 (Misoprostol) is also widely and effectively used for cervical ripening, it is often an 'off-label' use. PGE2 (Dinoprostone) is the agent specifically formulated and marketed for this indication.
Option C: Prostaglandin F2α (PGF2α) primarily acts on the myometrium (uterine muscle) to cause strong contractions, rather than on the cervix for ripening.
Option D: Prostaglandin I2 (PGI2 or Prostacyclin) is not used in labor induction or cervical ripening. Its main effects are vasodilation and inhibition of platelet aggregation.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Pharmacology of Cervical Ripening as background academic context rather than a clinical decision trigger.
Cervical ripening is a crucial first step in the induction of labor, especially when the cervix is unfavorable (low Bishop score). A successful ripening process significantly increases the likelihood of a successful vaginal delivery and reduces the rate of failed induction leading to cesarean section.
Nurses must closely monitor uterine activity and fetal heart rate after administering prostaglandins, as a key side effect is uterine tachysystole (excessively frequent contractions), which can compromise fetal oxygenation.
What if the patient has a previous cesarean section? The use of prostaglandins, especially Misoprostol (PGE1), is often contraindicated due to an increased risk of uterine rupture. In such cases, mechanical methods like a Foley catheter are preferred for cervical ripening.

How to Approach the Question

First, identify the core question: which prostaglandin is used for 'cervical ripening'.
Recall the different types of prostaglandins and their primary roles in obstetrics.
Differentiate between agents used for cervical ripening (acting on the cervix) and agents used for uterine contraction (acting on the myometrium).
PGE2 (Dinoprostone) and PGE1 (Misoprostol) are the main agents for ripening. PGF2α (Carboprost) is mainly for postpartum hemorrhage. PGI2 is not used in this context.
Between PGE1 and PGE2, recognize that PGE2 (Dinoprostone) is the classic agent specifically developed and approved for cervical ripening, making it the best answer.

Concept Tested & Keywords

QpNb41gCtZKi9y08W4aZR7

E6 Pharmacology Katzung 16e p. 527-529

E6 Obstetrics Williams p. 80-94

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