From the perspective of contraception, every menstrual cycle of women can be divided into menstrual period, ovulation period and safety period. Generally speaking,
Women of normal childbearing age only ovulate one egg per month. Eggs can survive for 1 ~ 2 days after expulsion, and sperm can survive for 2 ~ 3 days in female reproductive tract.
Fertilization ability is mostly within 24 hours after ovulation, and sperm loses its ability to combine with eggs after 2 ~ 3 days.
So you have sex 2 ~ 3 days before ovulation, and you may get pregnant 1 ~ 2 days after ovulation. This period is called easy pregnancy or dangerous period.
Women's ovulation date is generally around 14 days before the next menstruation. To be on the safe side, we will ovulate for the first 5 days and the last 4 days.
* * * 10 day including ovulation day is called ovulation period. Rest time other than menstrual period is called safety period.
The safety period is divided into pre-ovulation safety period and post-ovulation safety period. The period from the day when menstruation is clean to the day before ovulation is the safe period before ovulation.
The safe period after ovulation is from the first day after ovulation to the day before the next menstrual cramp. The safe period after ovulation is safer than that before ovulation.
This is because some women are sometimes affected by environmental changes and emotional fluctuations and ovulate in advance, so that the safety period before ovulation will be shortened unconsciously.
This will make the safe period before ovulation less safe. It is very rare for an ovary to ovulate twice in a menstrual cycle.
That is, the second ovulation will not occur from ovulation to the next menstruation, so the safe period after ovulation is safer.
The key to using safe period contraception is to determine the date of ovulation for women. When the ovary ovulates, there is generally no special feeling.
Although some women may have symptoms such as lower abdominal pain, backache, breast swelling and mood changes, these phenomena are not unique symptoms during ovulation.
Therefore, it cannot be used as a basis for ovulation. Menstruation and ovulation change periodically, and there is a close relationship between them. If we master their changing rules,
You can determine the date of ovulation indirectly. There are many ways to determine the date of ovulation, and the methods that women can master by themselves are:
According to menstrual cycle, the basal body temperature was calculated and measured, and the secretion of cervical mucus was observed.
What problems should be paid attention to in safe period contraception?
To use safe period contraception, we must first determine the ovulation period accurately. At present, the three methods used to determine ovulation period have their own advantages and disadvantages:
The ovulation period and the safe period before and after ovulation can be calculated by calendar method. But it only applies to women with normal menstruation.
Sometimes ovulation is advanced or postponed due to environmental changes and emotional changes, which is not accurate enough; The method of measuring basal body temperature can determine the date of ovulation and the safe period after ovulation.
The safe period before ovulation cannot be determined in advance. This method is both troublesome and strict. If you don't measure your body temperature according to the regulations, 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 combined, we can make full use of our strengths and avoid weaknesses and achieve greater results.
At least one of the couples can master the method of determining the ovulation period. If they can't master this method, they can't use safe period contraception.
Safe period contraception means stopping sexual intercourse during ovulation, which requires the close cooperation of the man, otherwise it cannot be used.
Of course, vaginal contraceptives can also be used during ovulation.
Why is contraception unsafe in safe period?
Safe period contraception is a physiological contraceptive method. Sexual life is carried out under normal circumstances, and you can get satisfied sexiness.
Compared with other drugs, instruments, surgery and other methods, it has the advantages of being natural, economical, practical and harmless, and is more easily accepted by people.
However, if it cannot be strictly mastered or improperly used, it will easily lead to failure.
The success of contraception in safe period depends on the understanding of ovulation period. Without this knowledge, security is out of the question.
Someone has done a survey in China, and it is 1/5 that lacks a correct understanding of safe-period contraception, and most people are still ignorant.
I don't know how to calculate ovulation period, which is one of the reasons for the low success rate of contraception in safe period.
In addition, women's ovulation time is influenced by external environment, climate, personal mood, health status and other factors.
Ovulation may be delayed or advanced, and additional ovulation may occur. Therefore, the safety period cannot be accurately calculated.
Therefore, contraception during the safe period is not safe.
Experts believe that the failure of contraception in safe period is largely due to ignorance of ovulation law. Call for popularizing knowledge of ovulation law.
Strengthen education. In the 1970s, two Australian doctors, John Billings and Evelyn Billings, based on the characteristics of periodic physiological changes in the female reproductive system,
The observation method of cervical mucus was initiated to determine the ovulation period and guide contraception. This method is called "Billings Natural Contraception Method" and has been recommended by the World Health Organization.
Although Billings method is accurate in measuring ovulation period, it is scientific and requires users to have certain cultural knowledge.
It needs the correct guidance of professional and technical personnel, and users must be trained and fully mastered before using it, so it is difficult to master it.
Because rhythm contraception is a kind of physiological contraception, it is only applicable to the laws of menstrual cycle, life and long-term cohabitation.
Couples who can cooperate and understand each other are not suitable for irregular menstrual cycle, visiting relatives and frequent changes in living environment.
For newlyweds, it is difficult to control the time of sexual life when they are newly married and very much in love, and it is also worthwhile to change their honeymoon trip and living environment.
Emotional excitement, ovulation period is difficult to master, and contraceptive failure is also "reasonable", so the wedding date is not suitable for this contraceptive method.