How to calculate ovulation accurately when menstrual cycle is irregular

Under normal circumstances, a woman's ovulation period is about fourteen days before the next menstruation. There are different algorithms for regular menstrual cycles and irregular menstrual cycles. As for how to calculate the ovulation period for irregular menstrual cycles, women can determine the ovulation period by measuring their basal body temperature.

1. Calendar method:

For women with irregular menstruation, the calculation can be based on the menstrual cycle of the past 6-12 months: the shortest cycle (number of days) - 21 days, and the period before is the previous safe period. The longest cycle (number of days) - 10 days, and the period after that is the post-safe period.

2. Observe cervical mucus

The cervical mucus is often dense in a small quantity, or even with no mucus at all after the menstruation is over. This is called the "dry period" and makes pregnancy difficult. In the middle of the menstrual cycle, with endocrine changes, mucus increases and becomes thinner, and vaginal secretions increase, which is called the "wet period". Near the ovulation period, the mucus is clear, smooth and elastic, like egg white, with high stringiness and not easy to break. The ovulation day is 48 hours before and after the last day of the appearance of this mucus. Therefore, when the vagina feels moist, it is the "fertile period". Therefore, for contraception, you need to wait until it is dry again for three full days and then have sexual intercourse after the fourth night.

3. Measure basal body temperature

Women usually ovulate when their basal body temperature rises from low to high before it rises. The three days when the basal body temperature is at an elevated level is the "fertile stage", and the three days after that is the safe period. This method can only indicate that ovulation has occurred, but cannot predict when ovulation will occur.

Measure and record your body temperature after waking up from 6 hours of adequate sleep and before engaging in any activities: Under normal circumstances, the body temperature rises by 0.3℃-0.5℃ after ovulation; if there is no ovulation, the body temperature does not rise and remains low throughout the entire cycle. It is necessary to test repeatedly and connect the points and lines in a chart for analysis. If your lifestyle is irregular, such as night shifts, business trips, insomnia, mood changes, illness, etc., this method cannot be used to determine whether ovulation has occurred.

4. The safe period is not necessarily safe

The calendar method (i.e. calculation based on the menstrual cycle) is often unreliable. The time of female ovulation is affected by factors such as the external environment, climate, her own mood, and health status, which may result in delayed or early ovulation, and extra ovulation may also occur. "The rhythm method is not completely safe." The failure rate of contraception during the safe period is about 20%. Relatively speaking, the contraceptive effect of having sex during the safe period after ovulation is more reliable when calculated using the basal body temperature method and cervical mucus method.