Q&A: Bulging belly button

Simon Strachan (paediatrician) answers:

This “sticky out” belly button is called an umbilical hernia. The umbilicus is the belly button and a hernia refers to the piece that sticks out. This appears in the area through which the umbilical cord passed at birth. The cord passes through the strong tendon that runs down the centre of the abdomen and the muscles of the tummy attach to this strong tendon. You can see this when you see someone who has well formed tummy muscles producing the “six pack”. The gap between the
six pack that runs vertically is caused by this tendon called the linea alba. When the cord drops off it leaves a little hole under the skin in the linea alba.

Sometimes this hole takes a long time to close and depending on the size of the hole the hernia can take as long as four years to close completely. As a child’s tummy muscles develop and the linea alba gets more pronounced, the hole closes. The tummy muscles get stronger once a child learns to sit, roll, stand and walk and this causes the linea alba to tighten and the hole closes.

The bit that sticks out is usually due to increased pressure that transmits through the hole from inside the abdomen. So when the child is calm and not crying the hernia will be fl at but will be pushed right out when the child is crying or moaning. The hernia hardly ever causes any problems and definitely does not cause colic, does not cause cramping and does not cause trapping of air.

One common practice is to place a coin over the hernia and wrap a bandage around the tummy to prevent the hernia from forming or sticking out. This does not make any difference to the hernia at all – it does not push it back in – and is not something that I would suggest.

On rare occasions, the hernia can cause a problem. This happens if a piece of bowel gets stuck through the hole. If this occurs you will notice that the child will be screaming in pain and vomiting, and that the hernia is very hard, red in colour and does not disappear when you push on it. If this occurs take your child to the doctor immediately.