Jaundice in newborns is caused primarily by a buildup of bilirubin in the blood, a condition known as hyperbilirubinemia. Bilirubin is a yellow substance produced when red blood cells are broken down. Normally, the liver processes bilirubin and helps remove it from the body through stool. However, in newborns, the liver is often immature and less effective at processing and eliminating bilirubin, leading to its accumulation and causing the yellow discoloration of the skin and eyes known as jaundice
. Several factors contribute to jaundice in newborns:
- Immature liver function: Newborns, especially preterm babies, have underdeveloped livers that cannot process bilirubin efficiently
- High red blood cell turnover: Newborns have a higher number of red blood cells that break down more rapidly, producing more bilirubin than adults
- Prematurity: Babies born before 38 weeks gestation are at higher risk because their liver is less mature and they may feed less, reducing bilirubin elimination
- Breastfeeding: Breastfed babies, particularly those with feeding difficulties or low intake, are more prone to jaundice. This includes breastfeeding jaundice (due to insufficient feeding) and breast milk jaundice (due to substances in the milk that slow bilirubin processing)
- Blood type incompatibility: If the mother's blood type differs from the baby's (e.g., ABO or Rh incompatibility), antibodies can cause rapid breakdown of the baby's red blood cells, increasing bilirubin levels
- Bruising during birth: Significant bruising or bleeding under the scalp (cephalohematoma) can increase bilirubin from the breakdown of red blood cells in the bruised area
- Genetic or enzyme deficiencies: Conditions like glucose-6-phosphate dehydrogenase (G6PD) deficiency or hereditary spherocytosis can make red blood cells more fragile and prone to breakdown
- Other health conditions: Infections, hypothyroidism, bile duct problems, or inherited disorders affecting bilirubin metabolism can also cause pathological jaundice
In most cases, newborn jaundice is physiological and resolves as the baby's liver matures and bilirubin production decreases within 1-2 weeks. However, if jaundice appears very early or is severe, it may indicate an underlying pathological cause requiring medical evaluation and treatment
. In summary, jaundice in newborns is caused by excess bilirubin due to immature liver function, increased red blood cell breakdown, feeding issues, blood type incompatibilities, bruising, or certain medical conditions
