Weight gain on the first day of your aunt is considered to be related to changes in hormone levels and increased appetite. 1. Hormone level changes: due to menstruation, the body fluctuates greatly in estrogen and progesterone levels, so the female body will appear water and sodium retention, the body’s cells, tissues, water increases in the lower extremities, or even cause generalized edema, which will cause a slight increase in body weight, generally at the end of the menstrual period, edema can be alleviated on their own. 2. Increased appetite: menstruation women’s appetite tends to increase, so the intake of food increases, and because of menstruation women to rest, exercise is reduced, so it will also lead to a slight increase in body weight. For women who gain weight on the first day of the aunt, generally do not need to be too nervous, if there are menstrual abnormalities, abdominal pain and other discomforts, it is recommended that they go to the gynecology department of the regular hospital as early as possible to clarify the cause of the disease under the guidance of the doctor and active treatment.