The lack of weight gain in the eighth month of a child’s life can be caused by insufficient nutritional intake, indigestion, chronic digestive diseases and other factors. 1. Inadequate nutritional intake: not gaining weight can be caused by inadequate nutritional intake. If the amount of breast milk is insufficient or the formula feeding method is inappropriate, it can lead to slow or no weight gain and not gaining weight. 2. Indigestion: When a child’s digestive function is disturbed and indigestion occurs, the intake and absorption of nutrients is poor, which can lead to the child’s lack of weight gain. 3. Chronic consumptive diseases: If a child has a chronic consumptive disease such as thyroid disease or tuberculosis, it can consume a large amount of body heat, resulting in the child’s lack of weight gain. Children do not gain weight in the eighth month, there may be other reasons, it is recommended to go to the hospital in time to improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.