How to calculate the safe period and ovulation period? Correct methods for judging female ovulation

Many female friends around them often use methods such as safe periods and extracorporeal ejaculation as contraceptive methods. The contraceptive results of these two methods are not very satisfactory. Due to the uncertainty of each woman's menstrual cycle and ovulation period, it is even more difficult to determine the true "safe period".

How to calculate the safety period scientifically

The method of calculating ovulation period based on menstrual cycle is also known as the calendar method. Menstruation and ovulation are both influenced by endocrine hormones in the pituitary gland and ovaries and exhibit periodic changes. The length of their cycles is consistent, with one cycle per month, and ovulation occurs between the two periods. Women's menstrual cycles vary in length, but the interval between ovulation and the start of their next menstrual cycle is relatively fixed, usually around 14 days. According to the relationship between ovulation and menstruation, the ovulation period can be calculated based on the menstrual cycle. The calculation method is to start from the first day of the next menstrual cycle, and the last 14 days or minus 14 days is the ovulation day. The ovulation day and its first 5 days and last 4 days together are called the ovulation period. This is the theoretical basis for the safe period contraception method.

For example, if a woman's menstrual cycle is 28 days and the first day of the current menstrual cycle is December 2nd, then the next menstrual cycle is December 30th (December 2nd plus 28 days). If 14 days are subtracted from December 30th, December 16th is the ovulation day. The ovulation period is from December 11th to 20th, which is the day of ovulation and the first 5 days and last 4 days. Except for the menstrual period and ovulation period, the rest of the time is a safe period, also known as the "seven up and eight down" period. During safe sex, there is no need to use any contraceptive drugs or tools.

To calculate the ovulation period using this method, it is first necessary to know the length of the menstrual cycle in order to calculate the start date of the next menstrual cycle and the ovulation period. Therefore, it can only be applied to women with a normal menstrual cycle. For women with irregular menstrual cycles, it is impossible to calculate the date of their next menstrual cycle. Therefore, it is also impossible to calculate the ovulation date and ovulation period.

Using the calendar method for contraception is prone to failure. Because some women can sometimes delay or advance ovulation due to health conditions, environmental changes, and emotional fluctuations, the estimated ovulation period based on the menstrual cycle is not accurate enough. According to foreign statistics, the failure rate of using the calendar method for contraception is 14.4% to 47%. Therefore, this method is only suitable for people with normal menstrual cycles, long-term living together, and the ability to correctly calculate the safe period. It is unreliable to use this method for individuals with irregular menstrual cycles, couples during family visits, and women with altered living environments.

How to determine the safety period

1、 Cervical mucus

Due to the fact that mature follicles in women can produce more estrogen, when reaching a certain level, that is, during ovulation, the cervical glands can secrete more mucus, which is about 3-30 times the usual amount. At this time, the mucus is thin, transparent, sticky, and water like, easily pulled into a filamentous shape. It can reach a length of 15-20 centimeters. If under a microscope, cervical mucus can be seen as crystals in the shape of fern leaves. At the same time, women can feel the cervix themselves, indicating that the outer opening of the cervix is outward during ovulation. The originally cartilaginous and hard cervical texture becomes soft, and a large amount of clear, smooth, and elastic mucus flows into the vagina, contracting the vagina to allow the mucus to discharge out of the vagina on its own.

It can be seen that these mucus droplets are smooth and transparent, and can be pulled into a filamentous shape by pinching them with your thumb and index finger, reaching over 10 centimeters. Be careful not to confuse the semen left after sexual intercourse with this mucus. The closer you approach ovulation, the more slippery, clear, and watery the mucus becomes. If an increase in vaginal secretions, i.e. an increase in cervical mucus, is detected, immediate measures such as avoiding sexual intercourse or using condoms should be taken, and changes in mucus should be noted. Persist until the cervical mucus becomes small, thick, and dry, for about 5-7 days. It is best to record the date of the increase or change in mucus on a monthly basis to explore its patterns.

2、 Measure basal body temperature

The body temperature of women can vary with the menstrual cycle, with lower body temperature during the menstrual and follicular periods, while higher body temperature during the luteal phase. During the first half of menstruation, it is usually above 36.8 ℃, which is caused by the secretion of progesterone in the body. Predicting ovulation requires drawing a baseline body temperature curve. You can use some small grid paper to mark the temperature scale at an equal distance on the vertical axis of the grid, starting from 36 ℃, using 0.1 ℃ as the grid, and reaching 37.5 ℃ for a total of 15 grids. On the horizontal axis of the grid, label each grid with the first, second, and third days of the menstrual cycle, with the menstrual period marked by X. Starting from the first day of menstruation, after waking up every morning, place the thermometer under the oral tongue before waking up, take it out for five minutes, and mark the reading on the horizontal and vertical coordinates on a grid paper, represented by a black dot. Some people also urinate in the urinal every morning after waking up, and then measure their urine temperature. Similarly, record the urine temperature reading on a grid paper, both of these methods can be used. Note that after each temperature measurement, the thermometer should be dropped below 36 ℃ for future use.

Then, connect the daily temperature black dots recorded on the grid paper into a curve. Generally, for normal women, their body temperature curve does not change much at the beginning, and it is not until the middle stage that their body temperature significantly increases. According to Jacques et al. from abroad, 95% of women experience hypothermia within 66 hours before ovulation, with 70.4% occurring 48 hours before ovulation, and the average ovulation time occurring 33 hours after hypothermia. Therefore, once a low temperature point occurs, it is necessary to avoid sexual intercourse or other contraceptive methods. It is generally believed that the accuracy rate is 80%.

3、 Measure saliva resistance

In recent years, it has been found that changes in female hormones before and after ovulation can cause changes in electrolytes in saliva. Therefore, the resistance value can undergo periodic changes. So some people use this principle to measure resistance to predict ovulation. The method is to spit out some saliva into a container after waking up every morning before exercising, measure it with an ohmmeter or multimeter, maintain a certain distance between two measuring rods, measure the resistance, and record the obtained values day by day, drawing a curve like measuring body temperature. After one cycle, it can be found that after the fifth day of the menstrual cycle, the resistance value can reach its first peak, and after three consecutive days of low value, a second peak can appear: ovulation often occurs during the 6-9 days after the first peak. Therefore, attention should be paid to abstinence or the use of condoms on the 4-10 days after the resistance value reaches its first peak. According to the same principle, some people abroad measure the resistance of the posterior fornix of the vagina and find that the lowest day of vaginal resistance per month is a signal that ovulation is about to occur. The combination of the two methods is more accurate.