Since every woman’s menstrual period and menstrual cycle is different, the number of days of safe period for clean menstruation varies from person to person. The so-called safe period, usually refers to the first day of menstruation seven days before and eight days after the first day of menstruation, due to this time there is usually no follicle growth and development of discharge, so it is called the safe period, generally coitus pregnancy chances are very small. If a woman’s menstrual cycle is 28 days, the menstrual period of 3 days, then after the menstrual period is clean, there are five days belong to the safe period, during this period of coitus do not take contraceptive measures, usually will not be pregnant, but does not mean that a hundred percent will not be pregnant, because the safe period is not a hundred percent safe, in the men and women coitus in the process of the stimulation of the sex life, but also may lead to the female abnormal ovulation and caused by the accidental pregnancy. If a woman’s menstrual cycle is 30 days, and the menstrual period is five days, then only two days after the menstrual period is clean belong to the safe period, because the safe period may also lead to women’s unwanted pregnancies, so now does not advocate through the calculation of the safe period for contraception, but should take appropriate contraceptive measures, you can take short-acting contraceptive pills, but also in the uterus to place the birth control device, you can let the male with condoms for contraception. For women who do not want to have children, safe period contraception is not necessarily safe, so it is recommended to use safe contraceptive methods.