Pregnancy is generally clinically known as gestation, and 22 weeks of gestation is roughly five and a half months, which is a mid-term pregnancy. Typically, a month is not 30 or 31 days in a typical month. Most hospitals in order to facilitate the calculation, 7 days a week, 4 weeks is counted as 1 month, the normal female gestation period is 40 weeks, exactly 10 months, that is, often referred to as October pregnancy, if the pregnant woman has been 22 weeks gestation, should be converted to five and a half months of pregnancy. Gestational period is calculated from the first day of the last menstrual period, clinically divided into three periods, the 14th-22nd week is called the middle pregnancy, is an important period of fetal growth and maturation of the development of various organs, the main manifestation of the uterus to enlarge and fetal movement, can be monitored through the Doppler instrument fetal heart rate, regular ultrasound to monitor the growth and development of the fetus.