This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Gynaecology & Obstetrics
[{'content': 'Emergency contraception prevents pregnancy by all of the following mechanisms, except: \nSelect and explain. \nA. Delaying/inhibiting ovulation, B. Inhibiting fertilization, C. Preventing implantation of the fertilized egg, D. Interrupting an early pregnancy', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Emergency Contraceptives are also called as INTERCEPTIVES.\nIt refers to a type of contraception that is used as an emergency to prevent pregnancy after an unprotected intercourse.\nMechanism of action\nThe mechanism of action is not known with certainty, but it is believed with justification that this treatment combines delay of ovulation (Option ‘a’) with a local effect on endometrium (Option “c”) and prevention of fertilization (Option “b”).\nAs far as option ‘d’ is concerned,\n“How much a post fertilization effect (option d) contributes to efficacy is not known, but it is not believed to be the primary mechanism”.\n“Contrary to popular belief, it is not an abortifacient i.e. will not act after implantation has occured”.\nMechanism of action of emergency contraception versus medical method of MTP.', 'role': 'assistant'}]