However, a much smaller number actually had hernias: only 23% of children, 8% of adults, and 15% of pregnant women.When the orifice is small (< 1 or 2 cm), 90% close within 3 years (some sources state 85% of all umbilical hernias, regardless of size), and if these hernias are asymptomatic, reducible, and dont enlarge, no surgery is needed (and in other cases it must be considered). Treatment
Children
In some communities mothers routinely push the small bulge back in and tape a coin over the palpable hernia hole until closure occurs. This practice is not medically recommended as there is a small risk of trapping a loop of bowel under part of the coin resulting in a small area of ischemic bowel. This "fix" does not help and germs may accumulate under the tape, causing infection. The use of bandages or other articles to continuously reduce the hernia is not evidence-based.An umbilical hernia can be fixed in two different ways. The surgeon can opt to stitch the walls of the abdomen or he/she can place mesh over the opening and stitch it to the abdominal walls. The latter is of a stronger hold and is commonly used for larger defects in the abdominal wall. Most surgeons will not repair the hernia until 5–6 years after the baby is born. Most umbilical hernias in infants and children close spontaneously and rarely have complications of gastrointestinal-content incarcerations.How far the projection of the swelling extends from the surface of the abdomen (the belly) varies from child to child.
Causes
The causes of umbilical hernia are congenital and acquired malformation, but an apparent third cause is really a cause of a different type, a paraumbilical hernia. Congenital
Congenital umbilical hernia is a congenital malformation of the navel (umbilicus). Among adults, it is three times more common in women than in men; among children, the ratio is roughly equal. It is also found to be more common in children of African descent. Acquired
An acquired umbilical hernia directly results from increased intra-abdominal pressure caused by obesity, heavy lifting, a long history of coughing, or multiple pregnancies. Another type of acquired umbilical hernias are incisional hernias, which are hernia developing in a scar following abdominal surgery, e.g. after insertion of laparoscopy trocars through the umbilicus. Paraumbilical
Importantly, an umbilical hernia must be distinguished from a paraumbilical hernia, which occurs in adults and involves a defect in the midline near to  the umbilicus, and from omphalocele. Diagnosis
Navels with the umbilical tip protruding past the umbilical skin ("outies") are often mistaken for umbilical hernias, which are a completely different shape. Treatment for cosmetic purposes is not necessary, unless there are health concerns such as pain, discomfort or incarceration of the hernia content. Incarceration refers to the inability to reduce the hernia back into the abdominal cavity. Prolonged incarceration can lead to tissue ischemia (strangulation) and shock when untreated. Umbilical hernias are common. With a study involving Africans, 92% of children had protrusions, 49% of adults, and 90% of pregnant women.