As pregnancy progresses and the fetus gradually develops, the gestational week is a good indication of how well the fetus is developing. There are various methods used to calculate the gestational week in clinical practice, the most common method of accounting operation is based on the last menstrual period. The first day of the patient’s last menstrual period is the starting date for the calculation of the gestational week, and the number of weeks of pregnancy is calculated every 7 days, based on the date of menopause. It is important to emphasize that the number of weeks to be counted may vary depending on the menstrual cycle of each individual. If a pregnant woman has a long menstrual cycle, then the due date should be delayed by a corresponding number of days, and if she has a short cycle, then the due date should be calculated earlier. It can also be inferred from the ultrasound results of the first pregnancy detected in the early stages of pregnancy. The gestational week can be inferred from the gestational sac, gestational bud and fetal heartbeat. For pregnant women whose last menstrual period is unclear and who have not had an antenatal checkup early in pregnancy, the gestational week can be roughly assessed based on the ultrasound examination or calculated based on the uterine height and abdominal circumference. However, the latter two methods of calculation are less accurate. In summary, the gestational week can be calculated based on the last menstrual period, ultrasound examination and uterine height and abdominal circumference.