An umbilical hernia is the most common type of hernia found in puppies and is not a medical condition or cause for immediate concern. A hernia is a protrusion or bulge of a part of the body tissue, fat, or an organ through an abnormal opening of the surrounding tissue. There are numerous types of hernias, each type named after its affected area. A hernia which can be pushed back into the abdomen is called reducible. Hernias which are not reducible are called incarcerated. If the blood supply to an incarcerated hernia is pinched off, the hernia becomes strangulated. A strangulated hernia is an emergency situation and must be brought to the attention of your veterinarian. The most common types of hernias in Shih Tzu puppies are: An umbilical hernia is the most common type of hernia found in puppies. In case of umbilical hernias, a portion of fat or internal organs protrudes through an incompletely closed umbilical ring. Umbilical hernias may be present at birth, or may be acquired. The most common means of acquiring an umbilical hernia is a result of the umbilical cord being severed too close to the abdominal wall. In most cases umbilical hernias are small and reduce as the puppy grows. Generally, by the time the pup is six months old, the umbilical hernia will shrink and disappear on its own.