The due date is not the exact date of delivery The due date, or the date when the pregnant woman is expected to give birth. Since it is difficult for every pregnant woman to accurately determine the time of conception, the medical rule is that the due date is calculated from the first day of the last menstrual period, and its entire pregnancy lasts for a total of 280 days and 10 gestational months (each gestational month is 28 days). The prenatal date is not a precise date of delivery, and the meaning of the prenatal date is not to indicate that the baby will definitely be born on the day of the prenatal date, only about 5% of women who are in natural labor happen to give birth on the prenatal date, and about 85% give birth within two weeks before and after the prenatal date, which is a normal range. Therefore, the due date is only a convenient reminder for mothers to know in advance when the baby will be born and to prepare for it. The due date is only an important reference for the birth of the baby, and it is important to check the symptoms of labor. Teach yourself to calculate the expected date of birth 1, according to the last menstruation calculation The month of the last menstruation date plus 9 or minus 3, for the number of months of the expected date of birth; the number of days plus 7, for the expected date of birth. Of course, the premise of this calculation method is that the female menstrual cycle is stable at 28 days, but the actual situation is different for each female cycle, and therefore need to be adjusted appropriately. 2.According to the date of fetal movement If you can’t remember the date of your last menstrual period, you can calculate it according to the date of fetal movement. Generally, the fetal movement starts at 18-20 weeks after pregnancy. The calculation method is: for first-time mothers, it is the day of fetal movement plus 20 weeks; for menstruating mothers, it is the day of fetal movement plus 22 weeks. 3.Calculation according to the basal body temperature curve The last day of the low temperature section of the basal body temperature curve is taken as the day of ovulation, and it is projected backward from the day of ovulation to 264-268 days, or plus 38 weeks. 4.According to the ultrasound examination, the gestational age can be estimated by measuring the inter-parietal diameter of the fetal head, head and hip length and femur length during the ultrasound, and the expected date of delivery can be projected (this method is mostly used as a diagnostic application of ultrasound examination by doctors). 5.Projected from the time of the beginning of pregnancy vomiting, the reaction to pregnancy vomiting usually occurs at the end of the 6th week of pregnancy, which is 42 days after the last menstruation, so the expected date of delivery is projected backward to 280 days.