The cycle from the first day after menstruation to the day before ovulation is generally 8 days, which is the last 8 days. From the first day after ovulation to the day before the next menstrual cramp, it is usually 7 days, which is the first 7 days. In the case of normal menstruation, the principle of safe period contraception is: the closer to the first day of menstruation, the safer it is, and the farther it is, the more dangerous it is, because the possibility of ovulation increases.
Normal women of childbearing age have 1 menstrual cycle every month, which is called 1 menstrual cycle from the beginning of this menstrual cramp to the next menstrual cramp. For example, from the perspective of contraception, every menstrual cycle of women can be divided into menstrual period, ovulation period and safety period.
Extended data
To use safe period contraception, we must first determine the ovulation period accurately. The ovulation period and the safe period before and after ovulation can be calculated by calendar method. However, it is only suitable for women with normal menstruation, and sometimes ovulation is advanced or postponed due to environmental changes, emotional changes and other reasons, which is not accurate enough.
The method of measuring basal body temperature can determine the ovulation date and the safe period after ovulation, but it cannot determine the safe period before ovulation in advance. This method is both troublesome and strict. If you don't measure your body temperature as required, you can't accurately determine the date of ovulation.
Cervical mucus observation method can determine ovulation period, safe period before ovulation and safe period after ovulation with high accuracy, but users must be trained and fully mastered before using it. If these three methods are used together, we can make full use of our strengths and avoid weaknesses and achieve greater results.
References:
Baidu encyclopedia-the first seven and the last eight