Taking birth control pills during menstruation is not good, for emergency contraceptive pills during menstruation generally do not need to eat, short-acting contraceptive pills need to start eating on the fifth day of menstruation, this time it is possible that menstruation is not yet clean. Long-acting contraceptive pills are also taken for the first time on the fifth day of menstruation. 1. Emergency contraceptive pills: belonging to the post mortem contraception, usually taken within seventy-two hours after sex. Sexual intercourse is prohibited during menstruation, so there is no need to take emergency contraceptive pills. 2. Short-acting contraceptive pills: start taking them on the fifth day of menstruation, no matter whether the period is clean or not, start taking them for twenty-one days or twenty-two days in a row, and after stopping the pills, you will have your period in three to seven days, and you will start taking the second course on the fifth day of menstruation. 3. Long-acting contraceptive pills: the first time you take the first tablet on the fifth day of menstruation, the second tablet on the twenty-fifth day of menstruation, remember this time, and then take a tablet every month according to this time. Warm tips, for any contraceptive pill, need to be taken under the guidance of a doctor, because the contraceptive pill are hormonal drugs, to avoid taking the endocrine disorders, such as discomfort, please consult the hospital in a timely manner.