A pregnant woman’s stomach suddenly becomes huge may be caused by obesity, but also may be caused by a huge child, as well as vitiligo and other diseases. 1. Obesity: If a pregnant woman eats too much high-calorie food during pregnancy, it will lead to the accumulation of calories in the body that can not be consumed, thus leading to obesity, and the pregnant woman will have a suddenly large stomach. 2. Huge children: Huge children are mainly due to a variety of factors such as the parents are tall, pregnant women eat more or diabetes. The main symptoms of patients are heavy abdomen, rapid weight gain, abdominal pain and so on, which will lead to the phenomenon of pregnant women suddenly become bigger. 3. Hyperemesis gravidarum: Hyperemesis gravidarum is mainly caused by the abnormal development of fertilized eggs, and the patient will have symptoms such as abnormal enlargement of the uterus, softness, and abdominal pain. The fetus will also lead to a small amount of vaginal bleeding, nausea and other symptoms, as well as vomiting and other symptoms. When a pregnant woman experiences a stomach that suddenly becomes huge, it may be caused by obesity and does not require treatment. If it is caused by a huge child or a disease, the patient needs to consult a doctor in time and follow the doctor’s instructions for treatment.