A normal woman of childbearing age has a menstrual cycle once a month, from the beginning of the current menstrual flow to the first day of the next menstrual flow, which is called a menstrual cycle. For contraceptive purposes, each menstrual cycle of a woman can be divided into menstrual period, ovulation period and safety period. Safety period contraception is a contraceptive method that stops sexual intercourse during ovulation. It is a traditional method of contraception and was one of the common contraceptive methods used at home and abroad before the introduction of the pill and IUD. A woman’s ovulation date is usually about 14 days before her next menstrual period. The egg can survive in the fallopian tube for 1 to 2 days after being discharged from the ovary to wait for fertilization; the man’s sperm can maintain fertilization ability in the woman’s reproductive tract for 2 to 3 days, so it is easy to conceive during intercourse in the days before and after the egg is discharged. For insurance purposes, we refer to the 5 days before and 4 days after the day of ovulation, together with the day of ovulation, as the ovulation period. Because intercourse during the ovulation period is prone to conception, it is called the risk period.
Classification
1. Pre-ovulatory safety period is the period from the day of menstrual cleansing to the day before the start of ovulation.
2. The post-ovulatory safety period is the period from the first day after ovulation to the day before the next menstrual period.
3. Comparison of the two types of safe periods The post-ovulatory safe period is safer than the pre-ovulatory safe period. This is because some women are sometimes influenced by environmental changes and mood swings that make ovulation early, so that the pre-ovulatory safety period is shortened without their knowledge, so that the pre-ovulatory safety period is not very safe. The chances of the ovaries ovulating twice in a menstrual cycle are extremely rare, i.e., the period after ovulation to the next menstrual period does not usually occur a second time, so the post-ovulatory safety period is safer.
The key to using a safe period for contraception is to determine a woman’s ovulation date. When the ovaries ovulate, there is usually no special sensation, even though some women may have symptoms such as lower abdominal pain, backache, breast swelling and mood changes, but these phenomena are not specific to ovulation and therefore cannot be used as a basis for ovulation. Menstruation and ovulation are cyclical and there is a close relationship between the two. If you have a good grasp of the changes in the two, you can determine the date of ovulation by indirect methods. There are many ways to determine the date of ovulation, and the methods that women can master on their own include: projecting from the menstrual cycle, measuring basal body temperature, and observing cervical mucus secretion.
Ovulation by menstrual cycle is also known as the calendar method. Both menstruation and ovulation are influenced by endocrine hormones from the pituitary and ovaries, and both cycles are the same in length, with one cycle per month, while ovulation occurs in the middle of two menstrual periods. Women have long and short menstrual cycles, but the interval between the day of ovulation and the start of the next menstrual period is relatively constant, usually around 14 days. Based on this relationship between ovulation and menstruation, ovulation can be projected according to the menstrual cycle. The method of calculation is to count down 14 days or subtract 14 days from the first day of the next menstrual period to the day of ovulation, and the day of ovulation and the 5 days before and 4 days after it are called the theoretical basis of ovulation. For example, if a woman has a 28-day menstrual cycle and the first day of her current period is on December 2, her next period will be on December 30 (December 2 plus 28 days), and then subtract 14 days from December 30, then December 16 will be the day of ovulation. The day of ovulation and the 5 days before and 4 days after it, that is, from December 11 to 20, are the ovulation period. Except for menstruation and ovulation, the rest of the time is considered safe. It is not necessary to use any contraceptive drugs or contraceptives to have intercourse during the safe period. To use this method to calculate ovulation, it is necessary to know the length of the menstrual cycle in order to calculate the start date of the next menstrual period and the ovulation period, so it can only be used for women with normal menstrual cycles. For women with irregular menstrual cycles, it is impossible to predict the date of the next menstrual period. Therefore, it is not possible to predict the day of ovulation and the period of ovulation.
The calendar method of contraception is prone to failure. Because some women may delay or advance ovulation due to health conditions, environmental changes and mood swings, the ovulation date calculated by the menstrual cycle is not correct. According to foreign statistics, the failure rate of the calendar method of contraception is 14.4% to 47%. Therefore, this method is only suitable for people who have normal menstrual cycles, live together for a long time, and can correctly calculate the safe period. This method is not reliable for people with irregular menstrual cycles, couples visiting relatives and women with changed living conditions.
Basal body temperature is the body temperature measured when the body wakes up after a long sleep and before any activity is performed.
The basal body temperature of normal women of childbearing age varies in a cyclic fashion, as does the menstrual cycle. This change in body temperature is associated with ovulation. Under normal circumstances, a woman’s basal body temperature is low before ovulation and increases after ovulation. This is because the corpus luteum formed after ovulation and the secretion of more progesterone stimulate the hypothalamic thermoregulatory center, causing the basal body temperature to rise and continue to fall until the next menstrual period. This change is repeated in the basal body temperature of the next menstrual cycle.
The basal body temperature measured every day is recorded on a temperature record sheet, and is linked to a curve, which shows that the body temperature is low in the first half of menstruation and rises in the second half of menstruation, this low temperature curve is called a biphasic temperature curve, which indicates ovulation of the ovaries, and ovulation usually occurs before the rise in body temperature or during the rise from low to high. Some people believe that the lowest point before the rise in temperature is the day of ovulation, but most do not exist, and only about 20% of women show this. The basal body temperature rises within 3 days, which is the fertile period, and from the 4th day until the next menstrual period, which is the “post-ovulatory safety period”.
Basal body temperature measurement only indicates that ovulation has occurred, but does not predict when ovulation will occur, so it can only determine the safe post-ovulatory period, not the safe pre-ovulatory period. If it is combined with the calendar method and the cervical mucus observation method, this problem can be solved.
In most cases, basal body temperature measurement is very reliable for determining the post-ovulatory safe period, but sometimes it is encountered that the temperature curve is irregular and therefore the exact time of ovulation cannot be determined, in which case safe contraception cannot be used.
In order to exclude these external and internal influences, the body temperature at 6-7 am before waking up is often taken as the basal body temperature. The basal body temperature is the lowest body temperature of the body during the day and night.
Although the method of measuring basal body temperature is simple, it is strict and requires long-term adherence. Before measuring, prepare a thermometer and a record sheet for basal body temperature (if there is no such sheet, a small square of paper can also be used instead), from the beginning of the menstrual period, in the early morning hours every day before waking up, without talking and without any activity, put the thermometer in the mouth for 5 minutes, and then record the measured temperature on the temperature record sheet.
To improve the correctness of basal body temperature measurement, the mercury column on the thermometer should be shaken off to below 35°C each night before going to bed and placed on the bedside table or by the pillow so that it is readily available for use and activity is minimized. If you get up to take the thermometer, it will raise the basal body temperature and make the temperature value of the day meaningless. For women who work mid-shift or night shift, place the basal body temperature measurement at the time of first awakening 4 to 6 hours after each bedtime.
Basal body temperature usually needs to be measured for more than 3 consecutive menstrual cycles to be indicative. If your menstrual cycle is regular, you will basically know your ovulation date after taking your basal body temperature for several menstrual cycles. To reduce the trouble, you can choose to start testing your body temperature 3 to 4 days before the ovulation date, and then just continue testing for another 3 to 4 days after the temperature rises, which means that you only need to measure the basal body temperature during the ovulation period for contraceptive purposes.
Correctly recording the basal body temperature on the temperature record sheet reflects the function of the ovaries. If it is not recorded correctly, it loses its meaning. Below is a graph of basal body temperature in a normal woman of childbearing age during a menstrual cycle. As seen in the graph, the first half of the body temperature is low and the second half of the body temperature is elevated, showing a typical biphasic body temperature curve. This temperature curve indicates that the ovaries are ovulating, and the junction of the high and low temperature curves is the ovulation date of the ovaries. The vertical axis of the graph indicates the degree of body temperature, with each small cell being 0.1°C. The horizontal axis coordinates indicate the date and the day of the menstrual cycle, with each small cell being 1 day. Starting from the first day of menstruation, the temperature measured each day is plotted with dots in the corresponding grid of the temperature recording sheet until the day before the next menstruation, and finally the dots are connected in order to form a basal temperature curve for one menstrual cycle. The black part of the graph indicates the menstrual period. In case of cold, fever, diarrhea, insomnia, alcohol consumption, use of electric blankets, etc., the basal body temperature is often easily affected and should be explained at the bottom of the table.
Measurement of basal body temperature Usage Measurement of basal body temperature in women of normal reproductive age has important medical uses. It is a simple, practical, easy to learn and relatively reliable method of self-monitoring ovarian function. It is a simple, practical, easy-to-learn and reliable method of self-monitoring ovarian function. Based on changes in basal body temperature, a woman’s ovarian function can be indirectly known, and the presence or absence of ovulation, the date of ovulation and luteal function can be predicted. Basal body temperature measurement is generally used for several purposes.
(1) To observe ovarian function. In normal women of childbearing age, the basal body temperature curve is biphasic, i.e. low in the first half of the menstrual cycle and high in the second half, which indicates normal ovulatory function of the ovaries. If the basal body temperature curve is monophasic (without the phenomenon of low first half and high second half), it means that the ovaries are not ovulating.
(2) Diagnosis of early pregnancy. Measurement of basal body temperature is one of the easiest and quickest ways to diagnose pregnancy. A woman with a regular menstrual cycle who suddenly stops menstruating and whose basal body temperature rises and then does not fall for more than 18 days can usually be diagnosed as pregnant. This is because after ovulation, the follicles form the corpus luteum, which secretes progesterone, which raises the body temperature, and if the egg is fertilized and pregnant, the corpus luteum continues to secrete progesterone, so the body temperature remains at a high level.
(3) To guide contraception. Basal body temperature can be measured to know a woman’s ovulation date, so that a safe period of contraception can be used.
(4) To guide fertility. Contrary to contraception, if you want to have children, you should choose to have intercourse during ovulation. Because basal body temperature measurement can determine a woman’s ovulation date, it can be used to guide fertility. In particular, certain women who are not easily pregnant can increase their chances of conception by scheduling intercourse during ovulation. The safety period contraception attention problems safety period contraception is a physiological contraceptive methods, sex is in a normal state, can get satisfactory sexy. But if you can not strictly master or use improperly, it can easily lead to failure.
The first thing to do is to accurately determine the ovulation period. The three methods currently used to determine ovulation have their own advantages and disadvantages: the calendar method can be used to project the ovulation period and the pre-ovulation and post-ovulation safety periods. However, it is only applicable to women with normal menstruation. Sometimes ovulation is advanced or delayed due to environmental changes and emotional changes, so it is not accurate enough; the basal body temperature measurement method can determine the date of ovulation and the post-ovulatory safety period, but not the pre-ovulatory safety period in advance, which is more troublesome and requires strict requirements. The cervical mucus observation method can determine ovulation and the safe period before and after ovulation with a high degree of correctness, but the user must be trained and fully mastered before using it. If these three methods are used in combination, they can be more effective and avoid the shortcomings.
The reliability of safe period contraception Safe period contraception is a physiological contraceptive method that is more acceptable to people because it has the advantages of being natural, economical, practical and harmless compared to other methods such as drugs, devices and surgery. Many people believe that the safety-period method of contraception prevents most unintended pregnancies. But now a new study has forced them to seriously change their minds that the safe period is actually not safe.
Safety-period contraception is a period of time during which a woman is not fertile, based on her ovulation period and the time that sperm and eggs survive in the female reproductive tract, so sexual intercourse is chosen to take place during this time, thus achieving contraceptive purposes. Usually ovulation occurs within 2 days before and after the 14th day of menstruation, so the safe period is about 10 days after menstruation and after the 20th day of menstruation until the next menstrual period, the closer to the menstrual period, the greater the possibility of contraception.
However, according to relevant information, this method is not safe, mainly for the following reasons.
1, the success of the safe period contraception, depending on the knowledge of ovulation, if the lack of knowledge in this area, safety is not to speak of. Some people in China have done a survey, on the safe period of contraception have a correct understanding of less than 1/5 of the surveyed population, most people are still ignorant, do not know how ovulation should be calculated, which is also one of the reasons for the low success rate of the safe period of contraception.
2, female ovulation time, by the external environment, climate, my emotions, and health status and other factors, ovulation can occur delayed or early, and there may be additional ovulation. Therefore, the safety period can not be calculated accurately, so that the safety period contraception is not safe.
The safety period is divided into the pre-ovulatory safety period and the post-ovulatory safety period. The period from the day of menstruation to the day before ovulation begins is the pre-ovulatory safety period. From the first day after the end of ovulation to the day before the next menstrual period is the post-ovulatory safety period. The post-ovulatory safety period is safer than the pre-ovulatory safety period.
This is because some women are sometimes affected by environmental changes and mood swings, which can lead to early ovulation, so that the pre-ovulatory safety period is shortened without their knowledge, making the pre-ovulatory safety period less safe. The chances of the ovaries ovulating twice in a menstrual cycle are extremely rare, that is, after ovulation until the next menstrual period, the second ovulation does not usually occur, so the post-ovulatory safety period is safer.
The most crucial thing is to determine the date of ovulation in women. When the ovaries ovulate, there is usually no special sensation, even though some women may have symptoms such as lower abdominal pain, lumbago, breast swelling and mood changes, but these phenomena are not specific to ovulation and therefore cannot be used as a basis for ovulation. Menstruation and ovulation are cyclical and there is a close relationship between the two. If you grasp the pattern of changes in the two, you can determine the date of ovulation by indirect methods.
The failure rate of safe period contraception is a physiological contraceptive method, sex is in a normal state, you can get a satisfactory sexy. However, if it cannot be strictly mastered or used improperly, it can easily lead to failure. According to the statistics of foreign experts, the failure rate of contraception using the safety period is as high as 14.4% to 47%. This method is only suitable for people who have normal menstrual cycles, live together for a long time, and can correctly grasp the projected safety period to use.
The reason for the high failure rate of safety-period contraception is related to the following two factors.
1, because the time of ovulation in women, by the external environment, climate, my emotional and health state and physical and other factors, so there will be ovulation delayed or early, and there may be additional ovulation, that is, twice in a month, which is one of the reasons for the high failure rate.
2. Since hormones in the body can also stimulate ovulation, when two people are having intercourse, if they are particularly excited, it will increase the secretion of hormones, which is likely to lead to ovulation. This is therefore one of the major reasons for the high failure rate.