What is the safe period?

The safe period is actually a way of contraception using the menstrual cycle. After a woman has her period, she will enter the menstrual period, safe period and ovulation period. Different periods will also change according to changes in menstrual timing. However, the safe period cannot guarantee absolute safety. If women want to prevent pregnancy by calculating the safe period, it is not safe and they still have to take other contraceptive measures.

The safe period is related to each person's longest cycle, shortest cycle, and the start time of menstruation. The safe period is not absolutely safe. Sometimes women ovulate earlier or later, and the judgment of the safe period becomes invalid at this time. Determining the safe period can only reduce the chance of pregnancy and cannot be used as a contraceptive method.

Normal women of childbearing age have menstruation once every 28 days or so. The period from the beginning of one menstruation to the first day of the next menstruation is called a menstrual cycle. For example, from the perspective of contraception, each menstrual cycle of a woman can be divided into the menstrual period, ovulation period and safe period.

Ovulatory contraception is a method of contraception that stops sexual intercourse during the ovulation period. This is a traditional contraceptive method and was one of the commonly used contraceptive methods at home and abroad before the advent of birth control pills and intrauterine devices.

The method of calculating ovulation according to the menstrual cycle is also called the calendar method. Both menstruation and ovulation are affected by endocrine hormones from the pituitary gland and ovaries and show cyclical changes. The length of their cycles is the same, both occurring once a month, and ovulation occurs between two menstrual periods.

Women's menstrual cycles vary in length, but the interval between ovulation and the start of the next menstruation is relatively fixed, usually around 14 days. Based on this relationship between ovulation and menstruation, the ovulation period can be calculated according to the menstrual cycle.

The calculation method is to count from the first day of the next menstrual period, and count down 14 days or subtract 14 days to get the ovulation day. The ovulation day and the 5 days before and 4 days after the ovulation day are called the ovulation period. This is the theoretical basis of the rhythm method of contraception.