Contraceptive pills are mostly made of estrogen and progesterone, and there are many types of contraceptives, including short-acting contraceptives, long-acting contraceptives and emergency contraceptives, and the first time you take contraceptives, you need to take them accurately, on time, and in the right amount according to the different kinds of pills. Classification of contraceptives 1, long-acting contraceptives: including compound norethindrone tablets, compound megestrol tablets, including levonorgestrel ethinyl estradiol tablets, etrogestrel, etc., the drug can be contraceptive for 1 month; 2, short-acting contraceptives: is a compound drug formulated by estrogen and progestin, contraceptive efficiency of more than 99%, but need to pay attention to the drug during the drug can not be intermittent; 3, emergency contraceptives: commonly used levonorgestrel tablets, Mifepristone, Mifepristone, Mifepristone, Mifepristone, Mifepristone and other contraceptives. Norethindrone tablets, mifepristone tablets, only one unprotected sex is effective, must be taken within 72 hours after sex, because more than 72 hours to eat emergency contraceptive pill may be a contraceptive failure, and eat emergency contraceptive pills, often in the withdrawal of bleeding 3-7 days after stopping the drug. Precautions If you are a patient with blood clots, uterine fibroids, high blood pressure, breast hyperplasia, it is not recommended to take contraceptive pills; after taking contraceptive pills there is a possibility of contraceptive failure, you need to pay attention to the next time the menstrual cycle is delayed, to detect whether the pregnancy. After taking birth control pills, some people will experience early pregnancy-like reactions, such as dizziness, headache, fatigue, drowsiness, loss of appetite, nausea, vomiting, as well as gastrointestinal reactions, menstrual disorders and so on.