It is not normal to have no weight gain in the 5th month of pregnancy, but it is normal to have no significant weight gain in the first 3 months of pregnancy, or even to have a light weight. After the third month of pregnancy, the pregnancy reaction disappears, the appetite increases, and the fetus grows significantly, then the weight should be increased, and the weight should be increased by about 20-30 pounds during the whole pregnancy. If the weight has not increased by the 5th month, you should pay attention to strengthening nutrition and increasing the diet in an appropriate amount to promote the growth and development of the fetus, in order to achieve the nutrients needed for the growth of the fetus.