This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Normal Menstruation, Abnormal Menstruation, Menopausal Physiology and forsight of conception, Subject name: Gynaecology & Obstetrics
[{'content': 'In a woman on DMPA injections for the past 1 year, the menstrual abnormality most commonly seen is: \nSelect and explain. \nA. Menorrhagia, B. Metrorrhagia, C. Polymenorrhoea, D. Amenorhoea', 'role': 'user'}, {'content': 'Answer: D \nExplanation: With continuous progesterone present in the body due to the injections, there is regular inhibition of estrogenic proliferation of the endometrium and hence the prolonged usage can result in total absence of endometrial proliferation and consequent amenorrhea. Intermenstrual bleeding or spotting may also occur.', 'role': 'assistant'}]