What is the primary mechanism of action of mifepristone when used for medical abortion?
It induces uterine contractions.
It acts as a prostaglandin analog.
It blocks progesterone receptors.
It inhibits folic acid synthesis.
The Correct Answer is C
Mifepristone is a synthetic steroid used for medical abortion. It works by antagonizing progesterone receptors, leading to decidual breakdown, cervical softening, and increased uterine sensitivity to prostaglandins. Progesterone is essential for maintaining pregnancy by stabilizing the endometrium and suppressing uterine contractions. Mifepristone is typically followed by misoprostol to induce uterine expulsion. Side effects include bleeding, cramping, nausea, and diarrhea. Contraindications include ectopic pregnancy, chronic adrenal failure, and long-term corticosteroid use.
Rationale for correct answer
3. Mifepristone blocks progesterone receptors, disrupting the hormonal support required to maintain the endometrial lining. This leads to decidual necrosis and detachment of the trophoblast. The question asks for the primary mechanism, which is receptor blockade, not downstream effects. This action initiates the abortion process before prostaglandins are administered.
Rationale for incorrect answers
1. Mifepristone does not directly induce uterine contractions. That role is fulfilled by misoprostol, a prostaglandin E1 analog given after mifepristone. While mifepristone increases uterine sensitivity to prostaglandins, its primary action is hormonal antagonism, not myometrial stimulation.
2. Mifepristone is not a prostaglandin analog. It is a steroidal compound that acts on hormone receptors, not prostaglandin pathways. Misoprostol, given after mifepristone, is the prostaglandin analog responsible for uterine contractions and cervical dilation.
4. Mifepristone does not inhibit folic acid synthesis. That mechanism is associated with drugs like methotrexate, which is used in ectopic pregnancy management. Mifepristone acts on progesterone, not folate metabolism, and has no antifolate properties.
Take home points
- Mifepristone blocks progesterone receptors to initiate medical abortion.
- Misoprostol is used after mifepristone to induce uterine contractions.
- Methotrexate inhibits folic acid synthesis and is used in ectopic pregnancy.
- Progesterone maintains pregnancy by stabilizing the endometrium and suppressing contractions.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is ["A","C","D"]
Explanation
Medical abortion involves pharmacologic termination of pregnancy using agents that induce uterine contractions and cervical dilation. The standard regimen includes mifepristone, a progesterone antagonist, followed by misoprostol, a prostaglandin E1 analog. Misoprostol causes uterine cramping, bleeding, and gastrointestinal effects. Expulsion typically occurs within 24 to 48 hours. Follow-up is essential to confirm complete evacuation and rule out retained products. Pain intensity varies, and analgesics are often required. Hemoglobin should be monitored if bleeding exceeds 500 mL.
Rationale for correct answers
1. Severe cramping and heavy bleeding are expected due to uterine contractions induced by misoprostol and decidual shedding. These mimic labor-like symptoms and are necessary for complete expulsion of the gestational sac. The question stem asks what to expect, and this is a physiologic response to the medication.
3. Follow-up is essential to confirm complete abortion and exclude retained products of conception, which can lead to infection or hemorrhage. Ultrasound or serial β-hCG levels are used. The question tests knowledge of post-abortion care, and this is a standard protocol.
4. Misoprostol commonly causes nausea and diarrhea due to its prostaglandin activity on smooth muscle. These side effects are dose-dependent and transient. The question asks about expected effects, and these are well-documented.
Rationale for incorrect answers
2. Expulsion is rarely immediate and never painless. Misoprostol induces strong uterine contractions and cervical dilation, which cause significant discomfort. Expulsion typically occurs within 24 to 48 hours, not instantly. The claim of painless and immediate expulsion contradicts the pharmacologic mechanism.
5. Pain medication is often required due to cramping and uterine contractions. NSAIDs like ibuprofen are commonly prescribed. The statement that no pain medication is needed is inaccurate and disregards patient comfort and standard practice.
Take home points
- Misoprostol causes cramping, bleeding, and gastrointestinal side effects during medical abortion.
- Follow-up is mandatory to confirm complete uterine evacuation.
- Pain management is essential; NSAIDs are commonly used.
- Medical abortion differs from surgical abortion in timing, symptoms, and monitoring.
Correct Answer is A
Explanation
Vacuum aspiration is a surgical method used for early pregnancy termination. It involves suction evacuation of uterine contents using a manual or electric vacuum source. It is most effective between 5 to 12 weeks gestation. The procedure requires cervical dilation, carries low risk of infection, and has a complication rate below 1%. It is contraindicated in ectopic pregnancy, coagulopathy, and severe pelvic infection. Compared to medical abortion, vacuum aspiration offers immediate completion and tissue confirmation.
Rationale for correct answer
1. Vacuum aspiration is most commonly used in the first trimester, specifically between 5 to 12 weeks gestation. At this stage, the uterine contents are soft and easily evacuated by suction. The question asks for the most common use, which aligns with early gestational termination where vacuum aspiration is standard.
Rationale for incorrect answers
2. In the second trimester, fetal size and ossification increase, making vacuum aspiration less effective. Dilation and evacuation (D&E) becomes the preferred method due to the need for forceps and ultrasound guidance. Vacuum aspiration is not routinely used beyond 12 weeks due to incomplete evacuation risks.
3. During the third trimester, termination is rare and legally restricted. Methods include induction abortion or cesarean delivery, not vacuum aspiration. The fetal size and viability make suction techniques inappropriate and unsafe. Vacuum aspiration is contraindicated due to high risk of uterine rupture and maternal morbidity.
4. Post-term pregnancy refers to gestation beyond 42 weeks, where termination is managed by labor induction or cesarean section. Vacuum aspiration has no role in post-term management. The uterus is large, the fetus is viable, and suction evacuation is neither effective nor safe.
Take home points
- Vacuum aspiration is preferred for abortion between 5 to 12 weeks gestation.
- D&E is used for second trimester termination due to fetal size.
- Third trimester termination requires induction or cesarean delivery.
- Post-term pregnancy is not managed with vacuum aspiration.
Whether you are a student looking to ace your exams or a practicing nurse seeking to enhance your expertise , our nursing education contents will empower you with the confidence and competence to make a difference in the lives of patients and become a respected leader in the healthcare field.
Visit Naxlex, invest in your future and unlock endless possibilities with our unparalleled nursing education contents today
Report Wrong Answer on the Current Question
Do you disagree with the answer? If yes, what is your expected answer? Explain.
Kindly be descriptive with the issue you are facing.