At which month of pregnancy will a baby be born?

For many young couples, the wife's pregnancy is a very happy thing. However, for new mothers, whether they have experience or not, they may not know some methods of calculating this time during pregnancy. The following editor will introduce to you in detail. Let’s quickly learn about the calculation methods of pregnancy and due 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).

【Main methods for calculating the expected date of delivery】

Calculated based on the last menstrual period: add 9 or subtract 3 from 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 February 1, 1985, month 2+9, date 1+7, and the expected date of delivery = November 8 (1985); the last menstrual period was April 15, 1985, month 4-3, date 15+7, and the expected date of delivery = January 22 (1986)

Calculated based on fetal movement date:

If you can't remember the date of your last menstrual period, you can calculate it 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.

(3) Calculated based on the basal body temperature curve:

The last day of the low temperature segment of the basal body temperature curve is regarded as the ovulation day, and the ovulation day is counted back 264-268 days, or 38 weeks.

(4) Calculation based on B-ultrasound examination:

When doctors perform B-ultrasound, they can measure the biparietal diameter of the fetal head, the crown-rump length and the 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).

(5) 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. The expected date of delivery is 280 days after the last menstrual period.

(6) Roughly estimate based on the height of the uterine fundus:

If you can't remember the date of your last menstrual period, you can roughly estimate the expected date of delivery based on the height of the uterine fundus. At the end of the fourth month of pregnancy, the height of the uterus is between the navel and the upper edge of the pubic bone (10 cm above the pubic symphysis); at the end of the fifth month of pregnancy, the fundus of the uterus is 2 horizontal fingers below the navel (16-17 cm above the pubic bone); at the end of the sixth month of pregnancy, the fundus of the uterus is level with the navel (19-20 cm above the pubic bone); at the end of the seventh month of pregnancy, the fundus of the uterus is three horizontal fingers above the navel (22-23 cm above the pubic bone); at the end of the eighth month of pregnancy, the xiphoid process of the fundus of the uterus is in the middle of the navel (24-25 cm above the pubic bone); at the end of the ninth month of pregnancy, the fundus of the uterus is 2 horizontal fingers below the xiphoid process (28-30 cm above the pubic bone); at the end of the tenth month of pregnancy, the height of the fundus of the uterus returns to the height at the eighth month, but the abdominal circumference is larger than that at the eighth month.

Is the due date accurate?

The due date is not the exact date of delivery. Scientists have calculated that only about 53% of women give birth on their due date. The due date does not mean that the baby will definitely be born on this day. It is just an approximate time. Birth within two weeks before or after the due date is considered normal. The due date can remind you of the time range for the safe birth of the fetus, but don't take the due date too precisely. By the 37th week of pregnancy, you should be prepared for delivery at any time, but don't be too anxious, just let nature take its course. If there are no signs of delivery by the 41st week of pregnancy, you should be hospitalized for observation or induced labor if conditions permit.

Through the above introduction, I think everyone should be clear now, so how long a woman's pregnancy lasts and how to accurately calculate the due date should be mastered by now. If we understand this knowledge in life, we can prepare in advance and deal with it before the birth comes.