1. The circumference of the abdomen, usually measured at the umbilicus, or also called belly button: The calculation of the abdominal girth is used to assess the growth of a baby, which is found to be an important indicator of normal baby proportions.
2. The measurement of the distance around the abdomen at a specific point, usually at the level of the belly button or navel: Measuring abdominal girth is used to diagnose and to monitor:

• Obesity, or the build up of fluid in the abdomen, often caused by liver failure or heart failure.
• Buildup of intestinal gas, usually caused by the blockage or an obstruction in the intestines.