According to the medical method of calculating the due date, doctors often project the due date based on the last menstrual period, which is the first day of the last menstrual period. Women who usually have regular menstruation usually start calculating from the first day of the last menstrual period, especially for the projection of the due date. The entire pregnancy period is 40 weeks, or 10 months. If a woman has a regular menstrual cycle of 28 days, the expected date of delivery will be calculated according to the solar calendar by adding 9 or subtracting 3 to the month and adding 7 to the number of days. if a woman usually has irregular menstruation and unstable cycles, the gestational age should be verified by early ultrasound examination, i.e. the size of the embryo sac by ultrasound examination and the comprehensive analysis of the gestational week by the time of gestational reaction or the time of the first fetal movement. However, the time of delivery varies from one pregnant woman to another due to her physical condition and fetal development, but usually delivery after 37 weeks of pregnancy is considered full-term. In addition, pregnant women should eat a balanced nutritious diet after pregnancy, avoid colds, weight bearing, exposure to harmful substances, etc. If you have bleeding, abdominal pain or other discomfort, you should consult a doctor in time.