How to calculate the date of pregnancy?

For any woman, conceiving a child is a major event in life. Many people even plan when to get pregnant, when to give birth, etc. perfectly for this important event. However, there are some women who don’t even know they are pregnant because of their careless personality, let alone calculate their pregnancy date. So how do you calculate your pregnancy date?

Since it is difficult for every pregnant woman to accurately determine the time of conception, medical regulations stipulate that the expected date of delivery is calculated from the first day of the last menstrual period. The entire pregnancy period is 280 days, or 10 gestation months (each gestation month is 28 days). Pregnant women gave birth between 38 and 42 weeks of gestation, all of which were full-term deliveries. Since the length of each woman's menstrual cycle is different, it is normal for the estimated due date to differ from the actual due date by 1-2 weeks.

The main calculation methods are as follows: Calculated based on the last menstrual period: Add 9 or subtract 3 to the month of the last menstrual period 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: The last menstrual period was March 13, 1999, and the expected date of delivery is approximately December 20, 1999. The last menstrual period was May 28, 1999, and the expected date of delivery is approximately February 5, 2000. The pregnant woman can also calculate backwards from the first day of the last menstrual period to the 280th day, which is the expected date of delivery.

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 18 and 20 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. Calculated according to the basal 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 the doctor does B-ultrasound, he 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 B-ultrasound diagnosis).

Calculate from the time when morning sickness starts: Morning sickness usually occurs at the 6th week of pregnancy, which is 42 days after the last menstrual period. Calculating backward from this to 280 days is the expected date of delivery.

After learning the above, we know several methods to calculate the date of pregnancy. Therefore, female friends who are planning to become pregnant or are already pregnant can calculate their pregnancy date carefully according to the methods introduced above. Only by calculating the date accurately can we prepare the necessary items according to the time and wait for the arrival of our new life.