Women’s ovaries will ovulate regularly, when they do not ovulate, they will not be pregnant, so it is called safe period. In fact, there is no absolute safe period in the whole menstrual cycle, because the ovulation time of the ovary will change. There is a contraceptive method called easy to know the pregnancy method, also called natural contraceptive method, which can be understood as “safe period contraception”.
Studies have shown that, The pregnancy period of a woman is from 5 days before ovulation to 24 hours after ovulation. The probability of conception after unprotected sex during this period of time is: 4% 5 days before ovulation, 25% ~ 28% 2 days before ovulation, It is 8% ~ 10% 24 hours after ovulation. These probabilities are related to the survival time of sperm in female genital tract (no more than 5 days), It is related to the survival time of eggs after ovulation (less than 24 hours). Therefore, the principle of this method is to determine the date of conception during the menstrual cycle by combining the length of the menstrual cycle with the physiological manifestations of the ovulation period, such as changes in cervical secretions and basal body temperature, and then avoid sex or use barrier contraception during this period.
Applicable population: Women who do not want to use other contraceptive methods for health or personal reasons.
Advantages: There are no side effects of drugs or other contraceptive methods, and the health will not be affected.
Disadvantages: It is more troublesome to observe vaginal secretions or test basic body temperature every day, calculate the date, and find one’s own easy pregnancy day through continuous attempts.
How to judge whether what is a safe period?
According to the length of the menstrual cycle: for women with a menstrual cycle of 26-32 days, the pregnancy period is the 8th-19th day of the menstrual cycle (the day when menstruation comes is the 1st day of the menstrual cycle).
According to cervical secretions: in the upcoming ovulation, ovulation period and shortly after ovulation, cervical secretions are large, clear, moist and have good wire drawing degree. The ovulation day can be predicted by observing vaginal secretions.
According to symptom body temperature: observing cervical secretions every day, the amount is large, clear, moist and wire drawing degree is good, which is an important sign of the beginning of pregnancy. However, after ovulation, the basal body temperature will rise by 0.3 ~ 0.5 degrees. Therefore, the rise in body temperature marks the end of pregnancy. By measuring the basal body temperature and observing secretions, the ovulation day can be retrospectively determined and the pregnancy day can be predicted.
Basal body temperature is also called resting body temperature. It is the body temperature measured completely without external interference. Usually after waking up every morning, Don’t get up, it is best to measure oral body temperature at the same time period, from the first day of menstruation to the end of the next menstruation, this is a complete basic body temperature measurement cycle. The premise of using this method is to ensure adequate sleep. If you often work night shift, or catch a cold and fever during body temperature measurement, the measurement is also inaccurate.
What is the contraceptive effect and matters needing attention in what?
According to the length of menstrual cycle, the annual contraceptive failure rate of people who can use this method completely and correctly is about 5%, and that of ordinary users is 12%.
According to cervical secretions, the annual contraceptive failure rate of people who can use this method completely and correctly is about 3%, and that of ordinary users is 23%.
According to symptom body temperature, the annual contraceptive failure rate of people who can use this method completely and correctly is about 2%, and the contraceptive failure rate of general users is 13% ~ 20%.
Relative contraindications:
1. Recent menarche, childbirth or discontinuation of certain hormone contraceptives;
2. Approaching menopause;
3. Currently in lactation period;
4. Women whose menstrual cycle is less than 26 days or more than 32 days; If there are two or more menstrual cycles in 12 months that are shorter than 26 days or longer than 32 days, it is not suitable to use the method calculated according to the length of the menstrual cycle.
5. Women who cannot correctly understand the signs of pregnancy continue to suffer from reproductive tract infection, which affects the judgment of secretions.
Note:
1. The failure rate of contraception in general use is higher than that of other contraceptive measures.
2. The menstrual cycle length calculation method is only applicable to women with menstrual regularity and 26-32 days. When using, sexual life or barrier contraception should be avoided on the 8th-19th (12th) of the menstrual cycle.
3. Women with too short, too long or irregular menstrual cycle can use cervical secretion observation method and symptom body temperature method: when using the method of observing cervical secretion changes, sexual life or barrier contraception need to be avoided for 14-17 days in each menstrual cycle; Using symptom body temperature method, 12-17 days in each menstrual cycle need to avoid sex or use barrier contraception.