The menstrual cycle is 25 days, the safe period is about 6 days before menstruation and 7 days after menstruation, ovulation is counted from the first day of the next menstrual period, counting down to 14 days for the day of ovulation, the first 5 days and the last 4 days of the day of ovulation together is called the ovulation period.
Safe period is about 6 days before menstruation and 7 days after menstruation, in the safe period for coitus can be effective contraception, although relatively safe, but the contraceptive effect is not 100%, it is best to choose a condom and other methods, so that the success rate of contraception will be higher, before and after coitus need to do a good job of cleaning, to avoid infection.
The day of ovulation is about 14 days before the next menstrual period, 5 days before the day of ovulation plus 4 days after the day of ovulation, a total of 10 days for the ovulation period. Projecting from time alone will have a large error, because life, emotions, sex, health conditions, drug use, external environment and other factors may lead to early or delayed ovulation.
Clinically, ultrasound, basal body temperature measurement, ovulation test paper test and other methods are generally used to determine whether you are in the ovulation period. For specific cases, it is recommended to consult a professional doctor.