Girls with a big belly may be physiological obesity, pregnancy, may also be pathological such as uterine fibroids, pelvic tumors, etc., need to be analyzed specifically. 1. Physiological: girls lack of exercise, long-term sedentary can lead to the accumulation of abdominal fat, manifested as a small belly, can be accompanied by weight gain and other manifestations, there may be no other discomfort. Female pregnancy can also appear small belly. 2. Pathological: common gynecological diseases such as uterine fibroids, pelvic tumors, when the size of the fibroids continue to increase, there can be an increase in the performance of the belly, but also with abdominal pain, vaginal bleeding, leukorrhea and other manifestations of abdominal ultrasound and other tests can assist in the definitive diagnosis. The cause of a girl’s belly may be physiological or pathological, it is recommended to consult a doctor in a timely manner, except for organic lesions, in order to prevent delays in the condition.