Clinically, there is no such thing as the first seven days and the last eight days. The first seven days and the last eight days are usually referred to as the safe period, which refers to the period seven days before and eight days after a woman’s period. Because the chance of ovulation is small, women who have intercourse during this period are less likely to get pregnant. This method is more suitable for women who have regular periods and only has a lower chance of conception compared to other periods, but there is still a certain chance of conception. It is recommended that the people who need contraception according to whether there is a plan to prepare for pregnancy, condoms, the pill as the preferred method of contraception, in addition, can also be selected according to the specific circumstances of ligation and other methods of contraception: 1, condoms: you can choose to use condoms for contraception, usually the success rate of contraception is about 85%. With the advantages of easy to use, no side effects, and help prevent the spread of AIDS, gonorrhea and other sexually transmitted diseases. It is recommended that before and after the use of careful observation of the condom rupture phenomenon, in order to avoid contraceptive failure; 2, the pill: mainly including emergency contraceptives, short-acting contraceptives and long-term contraceptives. If sex occurs without contraceptive measures, or condom rupture, women can choose to take oral emergency contraceptive pills in a timely manner to remedy, but it is not recommended to take long-term, so as not to cause certain adverse effects on the body. Contraception can be performed by taking some of the short-acting or long-acting contraceptive pills, usually without special hazards; 3. Ligation: for partners who have no long-term plans to prepare for pregnancy, for both men and women, that is, by cutting off the vas deferens or fallopian tubes and blocking the output of sperm or eggs. It has no effect on the ability of the male testes to produce sex hormones, or on erectile and ejaculatory function and pleasure after surgery. It is recommended to follow medical advice for post-operative care to avoid complications such as bleeding and infection; 4. Other: contraceptive injections, as well as female birth control rings, subcutaneous implants, intrauterine devices and other ways to contraception, but there may be certain side effects on the female body, and generally not recommended. Some women may be affected by their work and rest patterns, living habits, environmental changes, reproductive system diseases and other aspects that may lead to errors in ovulation and early or late ovulation. Therefore, it is not recommended to calculate the safety period according to the method of seven before and eight after.