Premature

In 1935, the American Academy of Pediatrics proposed that all live birth babies weighing 2500 g or less were premature. In the later clinical application process, it was recognized that there can be a large difference between the gestational age and the actual weight of the fetus when the fetal growth is restricted. Therefore, in 1961, the World Health Organization set the standard for gestational age of premature birth, which will reduce the number of weeks of pregnancy. Those born at 37 weeks are considered premature, but no lower limit is set. The term for the definition of preterm birth at home and abroad is not uniform. At present, the definition of preterm birth in China is calculated from the first day of the last menstrual period, and the child is born from 28 weeks to 37 weeks. People divide premature birth into 3 categories according to gestational age: 1. Extreme premature birth occurs at 20-28 weeks of pregnancy, accounting for 5%. 2. 32 weeks of pregnancy are early preterm labor, accounting for 10%. 3. Premature birth at 32-36 weeks of pregnancy is mild premature birth, accounting for 85%. Some scholars have further divided 32-36 weeks into two subgroups, calling 32-34 weeks as medium-term preterm labor, and 34-36. Weeks of preterm birth are called mild preterm births.