Produce a healthy baby is the hope of every prospective parent, with the improvement of family economic conditions, we are more and more attention to nutrition during pregnancy, after pregnancy deliberately to supplement additional “nutrition”. However, this is a misunderstanding, not the more you eat during pregnancy, the healthier your child will be. This is probably reflected in the increasing number of gestational diabetes and macrosomia in urban areas. Weight gain during pregnancy is directly related to nutrition during pregnancy. Excessive nutrition, excessive weight gain, increased chances of diabetes, the fetus because of excess weight, in labor and delivery relative to the small fetus is not easy to pass through the birth canal, prone to obstructed labor and injuries; and insufficient nutrition during pregnancy, the fetus will also be relatively undernourished manifestations, manifested in low birth weight, these children’s health problems are also more. So in the 9th month of pregnancy, how should the weight increase to be more appropriate? This question cannot be given a standard answer. People with different body types need to be treated differently. Overall, thin people can gain more weight, while fat people weight gain is relatively more strictly controlled. Distinguish between fat and thin, in medicine is to the body mass index (BMI) to express, BMI = weight / height 2 (weight divided by the square of height), which weight is in kilograms, height in meters, BMI normal value of 20 ~ 24 (kg / m2). Therefore to understand how much weight you need to gain during pregnancy, the first thing is to understand your pre-pregnancy BMI. 1, extremely thin body type (BMI less than 18), the weight gain throughout pregnancy is appropriate. 2, body type thin people (BMI between 18 to 20), the whole pregnancy weight gain 13 to 17kg is appropriate. 3, normal body type (BMI between 20 to 23), the whole pregnancy weight gain of 12kg is normal. 4, obese body type (BMI greater than 23), the whole pregnancy weight gain 8 to 11kg, can use some of the body’s energy reserves. 5, If it is a twin or multiple pregnancy, you should consult your doctor. Weight gain is related to the number of fetuses. Weight gain during pregnancy is not uniform. For normal weight people, a weight gain of 1 to 2 kg is more appropriate during the first trimester of pregnancy. Appetite may be affected during early pregnancy due to pregnancy reactions, but ensuring nutrition during this period is very important for fetal development. A study in Denmark found that malnutrition in the early stages of pregnancy resulted in higher chances of diabetes, hypertension and other diseases in the later years of a fetus’s life. Therefore, if the early pregnancy reaction is heavy to affect eating, it is advisable to take less food, vomit and eat again, and eat more food for the child’s brain development is beneficial. Protein, inorganic salts, vitamins and sugar are indispensable components of fetal brain development, so pregnant women should be diversified food, should not be too much taboo. Many pregnant women in the past after the pregnancy reaction stage, the appetite improves on the start of a large number of food, seems to make up for the shortfall in the early stage, this is also wrong, fetal growth and development has its own rules, excess nutrition will only be absorbed by the mother, resulting in obesity. The best way to gain weight is to increase slowly and steadily. In the middle and late stages of pregnancy, it is appropriate for normal-sized people to control their weight gain at about 0.5kg per week. Weight gain is too slow or stagnant growth, may suggest the existence of fetal growth backwardness, easy delivery of low-birth-weight children, these children are prone to a variety of diseases; too much weight gain during pregnancy or too fast, to become a chubby mother, for the mother and the fetus is not a good thing to increase too much weight, may suggest the existence of gestational diabetes, for mothers, too much weight gain, in the postnatal period is prone to Obesity and diabetes, for the fetus, too much weight gain too fast, it is easy to appear in the case of fetal giant (birth weight greater than 4kg) situation, giant child delivery is not easy to pass through the birth canal, the doctor chose cesarean section surgery delivery of the chances of large, in the process of delivery is easy to appear difficult to deliver, birth injuries, postpartum is also prone to hypoglycemia in newborns. Therefore, it is not better to eat as much as you can during pregnancy, but to focus on the quality of your diet rather than the quantity. If necessary, you may need to consult a dietitian to adjust your diet during pregnancy. Obese pregnant women are more likely to develop diabetes, hypertension, hyperemesis gravidarum, and venous thrombosis complications during pregnancy, so if you are planning to get pregnant, it is best to lose weight first. However, if pregnancy has been detected, it is not advisable to lose weight during pregnancy, and weight gain should be properly controlled under the guidance of a nutritionist.