Which hormone is administered for stimulation of uterine contraction?

WCL Staff Nurse - 2019

Obstetrics & Gynecology

Easy

Appeared in: WCL Staff Nurse - 2019

Explanation

Oxytocin is a hormone that directly stimulates the smooth muscle of the myometrium (uterine wall), causing it to contract.
It is the primary medication administered clinically for the induction (starting) and augmentation (strengthening) of labor.
The sensitivity of the uterus to oxytocin increases dramatically near term due to an increase in oxytocin receptors, making it effective for initiating labor.

Option A: Estrogen does not directly cause uterine contractions for labor. Its primary role is to prepare the uterus for labor by increasing the number of oxytocin receptors, making the muscle more sensitive to oxytocin's effects.
Option B: Fetal cortisol is part of the complex physiological cascade that signals fetal maturity and helps initiate labor naturally. It is not a hormone that is administered to a mother to induce contractions.
Option D: Progesterone has the opposite effect; it is a uterine relaxant (a tocolytic). It inhibits uterine contractions throughout pregnancy to prevent premature expulsion of the fetus.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Pharmacological stimulation of uterine contractions as background academic context rather than a clinical decision trigger.
Safe administration of oxytocin is a critical nursing skill. It is a high-alert medication due to the risk of uterine hyperstimulation (tachysystole), which can lead to fetal distress and uterine rupture.
Nurses must continuously monitor the fetal heart rate and contraction pattern, titrating the oxytocin dose according to protocol to achieve adequate labor without causing harm.
What if? If a patient on an oxytocin infusion develops uterine tachysystole (e.g., 6 contractions in 10 minutes) with fetal heart rate decelerations, the nurse's first action is to stop the infusion immediately. Subsequent actions include repositioning the mother, administering oxygen, and notifying the provider.

How to Approach the Question

This is a factual recall question testing knowledge of endocrine pharmacology in obstetrics.
First, identify the core of the question: which hormone is administered to stimulate uterine contractions.
Review the function of each hormone option in the context of pregnancy and labor.
Recall that Oxytocin is the primary uterotonic agent used clinically for labor induction.
Eliminate Progesterone, as it is a uterine relaxant (opposite effect).
Eliminate Estrogen and Fetal Cortisol, as they are involved in the natural preparation for labor but are not the drugs administered to directly cause contractions.

Concept Tested & Keywords

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E6 Physiology Guyton 4SAE Part 3 p. 65-67

E6 Pharmacology Nurses Shanbhag 3e p. 240-242

E6 Obstetrics Williams p. 13-28