The week of gestation is calculated from the first day of the last menstrual period and is usually 2 weeks before ovulation or fertilization and 3 weeks before implantation. Generally at the end of early pregnancy (end of 12th week), the fetus can move its limbs, at the end of middle pregnancy (end of 27th week), the fetus can move its limbs well and its eyes are half-open, and at the end of late pregnancy (end of 40th week), the fetus is mature enough to be born and can survive well.
1. Early gestation: at the end of 4 weeks, the embryonic disk and the body tip can be recognized; at the end of 8 weeks, the embryo takes on a human shape and the heart is formed; at the end of 12 weeks, the fetus’s limbs can be moved.
2. Middle gestation: at the end of the 16th week, the fetus can distinguish the sex, and the beginning of respiratory movements, some pregnant women can feel the fetal movement; at the end of the 20th week, swallowing and urination functions begin to appear; at the end of the 24th week, all internal organs have developed, and the skin is wrinkled; at the end of the 28th week, limbs are moving well, and the eyes are half-open.
3. Late pregnancy: at the end of the 32nd week, the weight of the fetus can reach 1700g, the skin is still wrinkled with dark red color, the ability to survive is still good, after birth, pay attention to the care of the baby can survive; at the end of the 36th week, the weight of the baby can reach 2500g, the body is rounded, the facial folds disappear; at the end of the 40th week, the fetus develops maturely, the skin is pink, and there are many subcutaneous fats, and the baby can survive well after birth.
Pregnant women should have regular checkups and seek timely medical attention if they find abnormal development of the fetus, so as to avoid hindering the development of the fetus.