Pregnancy is calculated on the basis of a 7-day week and a 28-day month. The gestation period is counted from the first day of the last menstrual period and is calculated on the basis of a 7-day week and a gestation month of 28 days, totaling approximately 280 days (40 weeks) for the entire pregnancy. It is generally divided into 3 clinical periods, with early pregnancy up to the 14th week of gestation, mid-pregnancy from the 14th to the 27th+6th week, and late pregnancy from the 28th week and onwards. During pregnancy, it is important to follow the doctor’s instructions strictly and take obstetric checkups on time. The week of pregnancy can be checked according to the ultrasound examination of early pregnancy, such as the size of the gestational sac, the size of the fetal buds and the length of the fetal head and buttocks, etc., so that the expected date of delivery can be more accurately projected. During pregnancy, you should also have a balanced diet under the guidance of your doctor to ensure the physiological needs of the mother and fetus, as well as proper physical exercise to maintain the appropriate growth of your body and facilitate natural delivery.