How to calculate the most accurate pregnancy duration

Many female friends cannot accurately calculate the duration of pregnancy, and new mothers are even more confused. In fact, the doctor can calculate the expected date of delivery very accurately. As long as you know the last menstrual period accurately, you will not make mistakes. So even if you don’t know how long the pregnancy is, it doesn’t matter. The doctor will tell you these common sense. Just take care of the fetus and wait for the baby to come.

The main reason is that it is difficult for every pregnant woman to accurately judge the time of conception. Generally, medical regulations stipulate that the first day of the last menstrual period is used to calculate the expected date of delivery. At the same time, the expected date of delivery is 280 days during the entire pregnancy period. For pregnant women in ten months of pregnancy, it is more accurate between 38 and 42 weeks of pregnancy.

.Calculate the month of the last menstrual period by adding 9 or subtracting 3 to get the month of the expected delivery date; add 7 to the day of the last menstrual period to get the day of the expected delivery date. For example: Ms. Zhang’s last menstrual period was March 13, 2008, and her expected date of delivery is approximately December 20, 2008. Ms. Li's last menstrual period was on May 28, 2008, so her due date is approximately March 5, 2009. The due date can also be calculated backwards from the first day of her last menstrual period to the 280th day.

Calculate based on the date of fetal movement: If you can't remember the date of your last menstrual period, you can calculate based on the date of fetal movement. Fetal movements usually begin between 16 and 22 weeks of pregnancy. The calculation method is: for primiparas, it is the day of fetal movement plus 20 weeks; for multiparas, it is the day of fetal movement plus 22 weeks. (General)

Calculated according to the body temperature curve: take the last day of the low temperature segment of the basal body temperature curve as the ovulation day, and count back 264-268 days from the ovulation day, or add 38 weeks.

Calculation based on B-ultrasound examination: When doctors do B-ultrasound, they can measure the biparietal diameter, crown-rump length and femur length to estimate the gestational age and calculate the expected date of delivery (this method is mostly used by doctors for diagnosis through B-ultrasound examination).

The above is how to calculate the pregnancy cycle. A woman's cycle varies in length, and it is difficult for each pregnant woman to accurately judge the time of conception. The general medical regulations stipulate that it is calculated based on the first day of the last menstrual period. The expected date of delivery is also 280 days during the entire pregnancy period. For pregnant women in ten months of pregnancy, it is more accurate between 38 and 42 weeks of pregnancy, so the methods of estimating the expected date of delivery are also different.