The abdominal wall consists of connective tissue, abdominal muscles and abdominal skin. It is not evenly formed everywhere and has weak points. One of these weak points is the navel. The abdominal wall is constantly exposed to enormous pressure - it holds our internal abdominal organs. When we cough, sneeze or lift, the pressure increases significantly. Pregnancy also puts pressure on the abdominal wall. An umbilical hernia forms when the connective tissue around the navel cannot withstand the pressure.

An umbilical hernia viewed from the side © Prof. Dr. med. Thomas W. Kraus
A gap is created in the abdominal wall, the so-called hernial orifice, through which the peritoneum bulges outwards. Doctors refer to the protrusion as a hernia sac. Sometimes parts of the intestine also protrude into the hernia sac. In rare cases, the hernia constricts the intestinal loops - they are no longer supplied with blood. An incarcerated umbilical hernia is an emergency, especially if parts of the intestine have prolapsed. There is a risk of parts of the intestine dying off. It therefore requires immediate surgery.
Statistically speaking,babies are far ahead when it comes to umbilical hernias - around one in ten suffer from them in this country. Premature babies with a birth weight of less than 1,500 grams are particularly at risk - two thirds of them are born with a congenital umbilical hernia. In adults, women are at a higher risk than men - they are around four times more likely to suffer from an umbilical hernia. Women between the ages of 50 and 60 are particularly at risk.
The navel is a natural weak point in the abdominal wall. During pregnancy, this is where the umbilical cord attaches, which supplies the embryo with all the essentials. After birth, the point at which the umbilical cord passes through slowly closes - the belly button is formed. However, the navel always remains a weak point as it only consists of thin layers of muscle and connective tissue.

Umbilical hernia viewed from above © Prof. Dr. med. Thomas W. Kraus
The navel also interrupts a stabilizing connective tissue suture that connects the tendon layers of the abdominal muscles. The so-called linea alba spares the navel area. This "white line" will be familiar to expectant mothers - this vertical suture is clearly visible during pregnancy. If the tissue around the navel cannot withstand the increased pressure in the abdominal cavity, a hernia occurs. The peritoneum now pushes through the resulting opening and forms a bulging skin pocket. If the hernia sac is large enough, intestinal loops can also squeeze into it.

Hernia sac of an umbilical hernia with prolapsed tissue © Prof. Dr. med. Thomas W. Kraus
The reasons for an umbilical hernia in babies are different. If the umbilical hernia is congenital, the causes can be traced back to embryonic development in the womb. After the 32nd day of pregnancy, a natural umbilical hernia develops in the embryo. At this stage of development, the intestinal loops grow faster than the abdominal cavity - parts of the intestine deviate into the umbilical cord due to lack of space. Normally, this umbilical hernia disappears on its own by the ninth week of pregnancy. Sometimes this is not the case and the baby is born with an umbilical hernia. Sometimes an umbilical hernia only develops in the first few weeks of life, before the tissue around the navel has completely closed. The still weak umbilical tissue cannot always withstand the pressure when coughing, crying or pushing.
- lifting heavy loads
- being significantly overweight
- pregnancy
- Genetic weakness of the connective tissue
- certain diseases (e.g. ascites, chronic lung disease or diabetes)
An umbilical hernia manifests itself in the baby as a soft bulge on the navel, which the doctor can push back into the abdomen. The size of the protrusion varies depending on the opening created - anything from the size of a cherry to the size of a tennis ball is possible. Smaller umbilical hernias only become apparent when crying or pushing. Normally, an umbilical hernia does not cause any discomfort.
Only when the abdomen is under increased strain (when lifting or coughing) does pain sometimes occur. This is not the case if intestinal loops are trapped in the umbilical hernia. Severe pain occurs very quickly. Babies cry continuously and the navel becomes dark in color. Immediate action is required in the case of an incarcerated umbilical hernia. Even if an umbilical hernia in babies is usually harmless and does not cause any discomfort, it is essential that it is clarified by a pediatrician or surgeon, usually avisceral surgeon or hernia surgeon.
Those affected complain of severe pain, nausea and vomiting in the event of an incarceration @ staras /AdobeStock
An umbilical hernia in a baby rarely requires treatment. In 90 percent of all cases, the umbilical hernia resolves on its own by the end of the second year of life. If this is not the case, an operation is necessary. However, there is no rush as long as the umbilical hernia remains inconspicuous. Surgical treatment is usually carried out before the child starts school.
As an umbilical hernia in adults does not usually regress, an umbilical hernia operation as part of hernia surgery is the only treatment option. The surgeon removes the resulting hernia sac and closes the hernial orifice by suturing the individual layers of tissue together.

Suture after umbilical hernia surgery with good cosmetic results © Prof. Dr. med. Thomas W. Kraus
If the hernial orifice is very large, the surgeon also inserts a reinforcing plastic mesh to prevent the umbilical hernia from recurring. In most cases, umbilical hernia surgery can also be performed using a minimally invasive keyhole technique. However, as only a single small incision is required directly on the navel for the operation, MIS procedures have not become widely accepted.