What Causes Umbilical Hernia?
Apr 22, 2022
Source: Cainiu Health
Dr. Zhang Weiling
Introduction
Some umbilical hernias occur because, after the umbilical cord is cut at birth, it gradually detaches over time. The umbilical scar region remains relatively weak due to the prior passage of the umbilical cord through the abdominal wall during fetal development—a site 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 defect.
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. Several factors contribute to its development. Typically, after the umbilical cord is cut at birth and subsequently detaches over time, a scar forms at the umbilical site. During fetal development, the umbilical cord passes through the abdominal wall, an area inherently weaker due to incomplete midline fusion of the bilateral rectus abdominis muscles. This results in a residual gap. When intra-abdominal pressure increases, abdominal contents may protrude outward through this defect, leading to umbilical hernia.
Secondly, infants undergo rapid physical growth and development after birth. During feeding, they may swallow air, leading to choking or coughing. Crying further exacerbates abdominal distension and elevates intra-abdominal pressure. Because newborns have underdeveloped abdominal musculature and poor contraction of the umbilical ring, increased pressure can cause the small intestine—along with the peritoneum and overlying abdominal skin—to protrude outward, resulting in umbilical hernia.
Prompt medical evaluation and management are essential following diagnosis of umbilical hernia. While many cases improve spontaneously as the child grows, some may worsen; therefore, regular monitoring and appropriate intervention are crucial.
