How to calculate the due date if the menstrual period is irregular

We all know that women have a due date before giving birth, and most women's due dates are related to their menstrual periods. If women's menstrual periods are not accurate, their due dates will definitely be affected. In addition, women's due dates are generally calculated based on the duration of pregnancy, and secondly, they are also related to the growth, development and weight of the fetus in the body. So how to calculate the due date if the menstrual period is not accurate?

How to calculate the due date most accurately

How to calculate the due date most accurately? The due date only predicts the time of delivery of the mother, not the exact date of delivery. The accuracy of the due date is only about 50%. There are many ways to calculate the due date, and some women and their families want to know if any of them are more accurate. So how can we calculate the due date most accurately? Generally, the due date is calculated based on the entire pregnancy period of 280 days. The specific method is: expected delivery month = month of the first day of the last menstrual period + 9 or -3, expected delivery days = days of the first day of the last menstrual period + 7. In this way, the calculated time is the expected date of delivery.

In fact, there are many methods to calculate the due date, including the reverse menstrual calculation method, the pregnancy calendar calculation method, the basal body temperature curve method, calculating from fetal movement, calculating based on morning sickness, etc. Among them, the basal body temperature curve method is a relatively accurate one.

In the basal body temperature curve, the last day of the low temperature period is the ovulation day. Add 38 weeks (266 days) to it, or add 9 to the month and subtract 7 from the day to get the expected date of delivery. The ovulation day can generally also be considered as the fertilization day, so this method is extremely accurate. If you can measure your body temperature continuously on a regular basis, you can find out whether you are pregnant as quickly as possible. As long as the high temperature lasts for more than 16 days, it may be a sign of pregnancy. If it lasts for 18 days, there is a 90% chance, 19 days is 95%, and more than 20 days, it is likely to be a sign of pregnancy.

It is worth noting that abortion, contraception or taking progesterone can also cause the body temperature to rise. At this time, you cannot judge whether you are pregnant based solely on the basal body temperature curve. There are many ways to calculate the due date, but none of them are absolutely accurate, because irregular menstruation, different fetal maturity times, the physical condition of the pregnant woman and other external factors can affect the advancement or postponement of the child's birth date. The so-called due date is only an approximate date of the child's birth. If a newborn is born 1 to 2 weeks earlier or later than the expected date of delivery, it is still considered a normal delivery. ...

Is B-ultrasound accurate in predicting the date of delivery?

There are many methods to calculate the due date, such as the reverse menstrual calculation method, the pregnancy calendar calculation method, the basal body temperature curve method, calculating from fetal movement, calculating based on morning sickness, etc. With the advancement of science and technology, some high-tech instruments are also used to calculate the due date. B-ultrasound is a common one. When a woman goes to the hospital for a B-ultrasound examination, the doctor can accurately calculate the due date based on the B-ultrasound examination. Generally speaking, doctors can estimate the gestational age and calculate the expected date of delivery by measuring the biparietal diameter, crown-rump length and femur length during B-ultrasound. But is this method of calculating the due date using high-tech instruments necessarily accurate?

The doctor said that the B-ultrasound calculation is based on the fetal development observed by the B-ultrasound, which can also be said to be a real-time situation, so the dynamic B-ultrasound detection is more accurate than the calculation based on the last menstrual period. However, B-ultrasound calculation of the expected date of delivery is not absolutely accurate. Generally, B-ultrasound can only roughly determine the number of days of pregnancy. In medical examinations, B-ultrasound can have an error of about one week.

All expectant mothers need to know is that the due date is only the date the mother expects to give birth, not the exact date of delivery. Scientists have investigated and found that only about 53% of women give birth on their due date. Therefore, the accuracy of the due date is only about 50%. No matter which of the due date calculation methods mentioned above, it is impossible to calculate the delivery period with 100% accuracy. Doctors say that delivery within two weeks before or after the due date is normal. As long as the delivery is within this normal range, expectant mothers do not need to be too nervous.