Family visit contraceptive pill need to start taking the drug the night before sex, continuous use of the drug until the end of family visits are effective, how long the effect of the drug lasted with the number of days to take, such as in the process of family visits to take 14 days, 14 days to have sex are contraceptive effect. Family visit contraceptive pill is a kind of quick-acting contraceptive pill, not as a regular contraceptive pill, commonly used family visit contraceptive pill 53 and norethindrone family visit tablets, mainly in the 12 hours after taking the drug can change the endometrial morphology and function, inhibit ovulation, so that the cervical mucus becomes sticky, not conducive to sperm penetration. Although taking the drug is not limited by the menstrual cycle, but need to take the drug on time and in the right amount, as long as you do not forget to take the drug, the contraceptive effect is good, if you do not take the drug on time is the case of unintended pregnancy.