In clinical practice, the pregnancy cycle is considered to be 1 month at 4 weeks, and 22 weeks of pregnancy is 5 months and 2 weeks, which is the middle of pregnancy. A woman’s pregnancy is measured in weeks, not in days of the natural month of 30-31 days. The normal full term of pregnancy is 280 days and the due date is after 40 weeks. The gestational age is calculated from the first day of the last menstrual period, during which time the follicles have begun to develop, and this is used to calculate the actual number of weeks of pregnancy, which is 2 weeks longer than the ovulation period and 3 weeks longer than the time of fertilization. If you are in doubt about the pregnancy cycle, you can go to the hospital for an ultrasound to accurately calculate the number of days of the pregnancy cycle, which is based on the growth characteristics of the fetus and is generally more accurate, especially for women with irregular menstrual cycles, the ultrasound pregnancy week is a relatively good reference. In addition, pregnant women should pay attention to regular maternity checkups during pregnancy to monitor the maturity of the placenta, the amount of amniotic fluid, the fetal position and the development of the fetus, and to seek medical attention in case of special conditions such as irregular vaginal bleeding and abdominal pain.