An abdominal swelling is an enlargement of the abdomen, which may be due to a variety of causes. Abdominal swelling is a natural result of obesity and enlargement of the uterus during pregnancy. Some causes of abdominal swelling are harmless. Wind in the stomach or intestine may cause uncomfortable, bloating distension. Distension as a result of temporary water retention may occur in some women just before menstruation. Other causes may be more serious. For instance, ascites (fluid accumulation in the abdominal cavity) may be a symptom of cancer or disease of the heart, kidneys, or liver; swelling may also be due to intestinal obstruction or an ovarian cyst.

Investigation 

Diagnosis of the underlying cause may involve X-rays (see abdominal X-ray), ultrasound scanning, laparotomy (surgical exploration of the abdomen) or laparoscopy (examination of the inside of the abdomen using a rigid or flexible viewing tube). In ascites, some of the fluid in the abdomen may be drained for detailed examination.