Kittens, like humans and dogs, have an umbilical cord that provides the body with nutrition when the kitten is in the womb. After delivery, the umbilical cord is laced off and the umbilicus is formed.
In some kittens, the abdominal wall has not been completely closed during the fetal period in the umbilical cord area and a so-called hernia port (opening in the abdominal wall) is formed where contents from the abdominal cavity can come out.
Umbilical hernia means that tissue from inside the abdominal cavity penetrates through the opening of the navel in the abdominal wall, which causes a bulge that is felt under the skin. The hernia contains only fat, but intestines or other abdominal organs can sometimes be found in the hernia. Umbilical hernias can range from a few millimeters to several centimeters. The diagnosis is made by feeling over the navel area.
Most umbilical hernias cause no problems for the cat and can be left without action. Larger hernias are corrected by surgery.
In the case of the larger umbilical hernias, one should be aware that the intestines can penetrate through the hernia port. If this happens, the blood supply can be restricted and the cat gets very sore and may need emergency surgery. The hernia swells and becomes hard and tender.
Umbilical hernia is significantly less common in cats than in dogs.