What Causes Umbilical Hernia?
Jul 07, 2022
Source: Cainiu Health
Dr. Xie Zixing
Introduction
Some umbilical hernias occur because, after the umbilical cord is cut at birth, it gradually detaches over time. The umbilical scar area remains relatively weak due to the prior passage of the umbilical cord through the abdominal wall during fetal development—a region inherently prone to weakness. At this stage, the left and right rectus abdominis muscles have not yet fully fused along the midline, leaving a potential gap. When intra-abdominal pressure increases, abdominal contents may protrude outward through this gap.
Umbilical hernia is an external abdominal hernia in which intra-abdominal contents protrude through a weak area at the umbilicus. In infants with umbilical hernia, a bulge—often hemispherical or sac-like—appears at the navel. There are several underlying causes.
Typically, after the umbilical cord is cut and subsequently detaches over time, a scar forms at the umbilical site. During fetal development, the umbilical cord passes through the abdominal wall—a region inherently weaker due to incomplete midline fusion of the bilateral rectus abdominis muscles. This leaves a natural gap. When intra-abdominal pressure increases, intra-abdominal contents may protrude outward through this defect, resulting in umbilical hernia.
Secondly, infants undergo rapid physical growth after birth. During feeding, infants often swallow air, which may lead to choking or coughing. Crying further exacerbates abdominal distension and elevates intra-abdominal pressure. In newborns, underdeveloped abdominal musculature and inadequate contraction of the umbilical ring render the abdominal wall less resistant to such pressure. Consequently, loops of small intestine—along with peritoneum and overlying skin—may be pushed outward, causing umbilical hernia.
Prompt treatment is essential upon diagnosis of umbilical hernia. While many cases show marked improvement as the child grows older, some may worsen; therefore, regular monitoring and appropriate intervention are crucial.
