Weight control for pregnant mothers is one of the most important factors in ensuring the health of both mother and baby. Normal weight gain during pregnancy is a sign of balanced nutrition for the mother, healthy growth of the fetus and a reflection of a normal course of pregnancy. Therefore, weight measurement during each pregnancy checkup is a mandatory item. When the pregnancy weight abnormalities, need to cause pregnant mothers pay close attention. Abnormal one, increase excessive 1, aggravate the burden on the cardiovascular system, easy to induce gestational diabetes and gestational hypertension and other pregnancy complications. 2, obesity during pregnancy has adverse effects on both mothers and newborns, increasing the incidence of obstructed labor, prolonged labor, postpartum hemorrhage and the incidence of neonatal asphyxia. 3, obese pregnant mothers with thick abdominal wall fat, prenatal examination is more difficult, easy to lead to the omission of genetic conditions during pregnancy, such as abnormal fetal position, amniotic fluid, too much, too little, huge fetus and so on. 4, excessive obesity also affects smooth labor and delivery, increasing the rate of cesarean section. It is also prone to postoperative complications such as bleeding, incision infection and delayed healing. 5, excessive weight gain pregnant mothers deliver babies Apgar score is generally lower, and easy to complicate hypoglycemia, meconium aspiration syndrome. Abnormal two, weight gain is too small 1, may be due to unbalanced or insufficient nutritional intake caused by maternal malnutrition, pregnancy anemia, low protein, endocrine disorders, immune system disorders. 2. Insufficient nutrition of pregnant mothers, physical weakness, and insufficient force of labor, resulting in difficult or surgical delivery, slow post-partum recovery, or affecting the secretion of breast milk. Due to insufficient nutritional intake of the pregnant mother, the fetus baby can not get enough nutrition from the mother’s body, resulting in restricted fetal development, low weight, miscarriage or premature birth. Fetal babies have poor insulation ability after birth, and their whistling and metabolic functions are weaker, which makes them particularly vulnerable to infections and diseases, and the mortality rate will be much higher than that of newborn babies with normal weight.