The goal of weight management during pregnancy: to control weight within a reasonable range, avoid overweight or underweight, and help reduce the occurrence of pregnancy-related illnesses. The dangers of abnormal weight during pregnancy for mother and child: 1. Excess weight before pregnancy can increase congestive heart failure, non-insulin-dependent diabetes mellitus, and reduce quality-adjusted life. Increased incidence of macrosomia; 2. Excess weight during pregnancy increases the incidence of gestational hypertension, increases the rate of obstructed labor and cesarean delivery, intrauterine distress and neonatal asphyxia, late fetal death, and increased risk of neonatal death; 3. Low weight during pregnancy leads to low birth weight babies, fetal growth restriction, and increased preterm births. 4, abnormal weight during pregnancy can affect the long-term health of the offspring: maternal weight gain is insufficient, the offspring may occur in the long term hypertension, dyslipidemia, cardiovascular disease, insulin resistance, etc.; maternal weight gain is too much, the offspring may occur in the long term obesity, metabolic syndrome, cardiovascular disease, etc. Therefore, the scientific management of weight during pregnancy is of great significance to the health of mother and child. Three major interventions are recommended for weight management during pregnancy: 1. dietary nutrition to meet the physiological needs of pregnant women and fetuses and ensure nutritional balance during pregnancy; 2. energy consumption generated by moderate exercise can regulate weight gain during pregnancy; 3. establishing a good lifestyle and correcting bad habits. Use BMI to set the weight gain target during pregnancy Pre-pregnancy BMI: ∠18.5 KG/m2 Underweight, 12.5-18 KG growth is recommended during pregnancy. Pre-pregnancy BMI: 18.5-24.9 KG/m2 Normal weight, 11.5-16 KG growth is recommended during pregnancy. Pre-pregnancy BMI: 25.0-29.9 KG/m2 Obese weight, recommended to increase 5-9KG during pregnancy.