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': 'Oral contraceptive pills cause all except : \nSelect and explain. \nA. Dysmenorrhea, B. Mastalgia, C. Nausea, D. Chloasma', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is a i.e. Dysmenorrhea OCP's have antiovulatory effect and by viue of this propey, relieve dysmenorrhoea (rather than causing it), Premenstrual tension and Mittleschmerz syndrome.", 'role': 'assistant'}]