Which drug blocks progesterone to terminate an intrauterine pregnancy when used with misoprostol?

Which drug blocks progesterone to terminate an intrauterine pregnancy when used with misoprostol?

• A. Misoprostol
• B. Mifepristone
• C. Methotrexate
• D. Estrogen

Answer: (B)

Blocking progesterone to terminate an intrauterine pregnancy works by using a progesterone receptor antagonist. Mifepristone binds to those receptors and blocks progesterone’s action, leading to breakdown of the endometrium and decidual tissue. When combined with misoprostol, a prostaglandin that induces cervical ripening and strong uterine contractions, this sequence efficiently causes the pregnancy to be expelled. Misoprostol alone can induce abortion but is more effective when progesterone action is blocked; methotrexate is used in other contexts (often with misoprostol for certain ectopic pregnancies or selected medical abortions) and does not block progesterone, while estrogen is not used for terminating pregnancy.

Blocking progesterone to terminate an intrauterine pregnancy works by using a progesterone receptor antagonist. Mifepristone binds to those receptors and blocks progesterone’s action, leading to breakdown of the endometrium and decidual tissue. When combined with misoprostol, a prostaglandin that induces cervical ripening and strong uterine contractions, this sequence efficiently causes the pregnancy to be expelled. Misoprostol alone can induce abortion but is more effective when progesterone action is blocked; methotrexate is used in other contexts (often with misoprostol for certain ectopic pregnancies or selected medical abortions) and does not block progesterone, while estrogen is not used for terminating pregnancy.