Which drug is used to induce abortion by blocking progesterone receptors?

Which drug is used to induce abortion by blocking progesterone receptors?

• A. Leuprolide
• B. Zidovudine
• C. Misoprostol
• D. Mifepristone

Answer: (D)

Blocking progesterone signaling is how some medical abortions are achieved. Progesterone helps maintain the uterine lining and pregnancy; when its action is blocked, the decidua breaks down and the pregnancy tissue can detach. The drug that directly blocks progesterone receptors is mifepristone. It binds with high affinity to these receptors, preventing progesterone from acting, which initiates decidual breakdown. Because the pregnancy tissue then needs stimulation to be expelled, mifepristone is usually given with misoprostol, a prostaglandin that induces strong uterine contractions and cervical ripening to complete the abortion. This regimen is commonly used in the first trimester (often up to about 10 weeks gestation). Leuprolide suppresses gonadotropin release rather than blocking progesterone receptors; zidovudine is an antiviral; misoprostol alone can induce abortion by contractions but does not block progesterone receptors, so the agent that acts specifically as a progesterone receptor blocker is the correct choice.

Blocking progesterone signaling is how some medical abortions are achieved. Progesterone helps maintain the uterine lining and pregnancy; when its action is blocked, the decidua breaks down and the pregnancy tissue can detach. The drug that directly blocks progesterone receptors is mifepristone. It binds with high affinity to these receptors, preventing progesterone from acting, which initiates decidual breakdown. Because the pregnancy tissue then needs stimulation to be expelled, mifepristone is usually given with misoprostol, a prostaglandin that induces strong uterine contractions and cervical ripening to complete the abortion. This regimen is commonly used in the first trimester (often up to about 10 weeks gestation). Leuprolide suppresses gonadotropin release rather than blocking progesterone receptors; zidovudine is an antiviral; misoprostol alone can induce abortion by contractions but does not block progesterone receptors, so the agent that acts specifically as a progesterone receptor blocker is the correct choice.