Pregnant women begin to gain weight significantly around the fourth month of pregnancy, but there are individual differences. Weight gain during pregnancy comes mainly from the fetus, the uterus and its contents, the breasts, increased blood volume, intertissue fluid, and maternal fat and protein stores. After four months of pregnancy, the early pregnancy reaction basically disappeared, the fetus in the uterus began to develop rapidly, and the weight of the fetus increased, resulting in pregnant women need to consume more nutrients and energy to supply the development of the fetus, which makes the pregnant woman’s body weight grow gradually, so the pregnancy in about four months of body weight began to increase. After pregnancy, the average weight gain during the whole pregnancy is 12.5kg, lean, fat or overweight pregnant women, it is recommended to go to a regular hospital by a professional physician for your nutritional guidance during pregnancy, reasonable weight gain.