Physiological changes during pregnancy

Pregnancy is divided into three stages: early, middle and late. Early pregnancy is before the 12th week of pregnancy, mid-term pregnancy is from the 13th week to the 27th week, and late pregnancy is the 28th week and beyond. After pregnancy, a series of significant physiological changes occur in various systems throughout the body to meet the increasing physiological burden and continue throughout the pregnancy. These changes gradually return to the physiological state before pregnancy 2-6 weeks after delivery.