Umbilical hernia is an inheritable condition in dogs. Insufficient research has been completed in cats to know whether inheritance is a factor.
Just as in people, the umbilicus, or navel, serves as the attachment location for blood and waste products to be exchanged from the mother to her offspring while still in the womb.
The body is programmed to close the defect in the abdominal wall when the umbilical cord is no longer needed, but in some individuals that closure doesn’t occur.
What happens next is an interesting case of the body “giving up.” Instead of attempting to continue to heal the opening over time, fibrous tissue forms and ensures that the fistula will remain patent.
Umbilical hernias come in all sizes. I saw one in a little Schnauzer once that was as big as a silver dollar. As is common, when one genetic defect occurs others may accompany it, and this little dog also had a blood disorder.
Ironically, the smallest openings are the most dangerous. Should tissues from the abdomen enter the opening tightly enough to lose their circulation, the structures become strangulated and the tissues die. That becomes a surgical emergency.
Thirty years ago these defects were treated much more aggressively than they are today. Our soft tissue surgery professor taught us that hernias were composed of abnormal tissue,which is subject to surgical failure and, as such, should always be closed with stainless steel suture. That way the suture would always be in the body and the opening could never relapse. Absorbable sutures have progressed dramatically in three decades. Now we remove the abnormal tissues generously and place suture material that will be removed by the body after it is no longer needed.
Umbilical hernias are almost always diagnosed in very young animals and surgical repair is usually delayed until the pet is sexually altered. One anesthesia, two surgical procedures, less strain on the patient.
If your puppy or kitten has an umbilical hernia it will be monitored closely by your pet’s doctor, but you should check it every day as well, and report any pain to your veterinarian immediately.
Furthermore, pets with umbilical hernias should never be bred, because the likelihood of passing on the genetic defect is very high.