The cause of jaundice is excess bilirubin, a waste product produced when red blood cells are broken down.
Jaundice is particularly common in premature babies - boys more often than girls. It usually appears within the baby's first week of life.
In an otherwise healthy baby born at full term, infant jaundice is rarely a cause for alarm; it tends to go away on its own. However, if treatment is necessary, infants tend to respond to non-invasive therapy.
In rare cases, untreated infant jaundice may lead to brain damage and even death.
Causes of infant jaundice
Infant jaundice is caused by an excess of bilirubin. Bilirubin is a waste product, produced when red blood cells are broken down. It is normally broken down in the liver and removed from the body in the stool.
Before a baby is born, it has a different form of hemoglobin. Once they are born, they very rapidly break down the old hemoglobin. This generates higher than normal levels of bilirubin that must be filtered out of the bloodstream by the liver and sent to the intestine for excretion.
However, an underdeveloped liver cannot filter out the bilirubin as fast as it is being produced, resulting in hyperbilirubinemia (an excess of bilirubin).
Infant jaundice with breast-feeding is common. It occurs in newborns that are breast-fed in two separate forms:
- Breast-feeding jaundice - occurs in the first week of life, if the baby does not feed well, or if the mother's milk is slow to come in.
- Breast milk jaundice - this is due to how substances in the breast milk interfere with the breakdown process of bilirubin. It occurs after 7 days of life, peaking at 2-3 weeks.
Some cases of severe infant jaundice are linked to an underlying disorder; these include:
- liver disease
- sickle cell anemia
- bleeding underneath the scalp (cephalohematoma) - caused by a difficult delivery
- sepsis - a blood infection
- an abnormality of the baby's red blood cells
- blocked bile duct or bowel
- rhesus or ABO incompatibility - when the mother and baby have different blood types, the mother's antibodies attack the baby's red blood cells
- higher numbers of red blood cells - more common in smaller babies and twins
- enzyme deficiency
- bacterial or viral infections
- hypothyroidism - underactive thyroid gland
- hepatitis - an inflammation of the liver
- hypoxia - low oxygen levels
- some infections - including syphilis and rubella
Risk factors for infant jaundice
Common risk factors for infant jaundice are:
- Premature birth - premature babies have severely underdeveloped livers and fewer bowel movements, this means there is a slower filtering and infrequent excretion of bilirubin.
- Breast-feeding - babies who do not get enough nutrients or calories from breast milk or become dehydrated are more likely to develop jaundice.
- Rhesus or ABO incompatibility - when a mother and baby have different blood types, the mother's antibodies go through the placenta and attack the red blood cells of the fetus, causing accelerated break down.
- Bruising during birth - this can make red blood cells break down faster, resulting in higher levels of bilirubin.
Symptoms of infant jaundice
The most pervasive sign of infant jaundice is yellow skin and sclerae (the whites of the eyes). This typically starts at the head, and spreads to the chest, stomach, arms, and legs.
Symptoms of infant jaundice can also include:
- pale stools - breast-fed babies should have greenish-yellow stools, while those of bottle fed babies should be a greenish-mustard color
- poor sucking or feeding
- dark urine - a newborn's urine should be colorless
Symptoms of severe infant jaundice include:
- yellow abdomen or limbs
- inability to gain weight
- poor feeding
How is infant jaundice diagnosed?
Doctors recommend that babies be tested for jaundice before being discharged from the hospital and again 3-5 days after birth, when bilirubin levels are highest.
Doctors will most likely diagnose jaundice based on appearance alone. However, the severity of jaundice will be determined by measuring levels of bilirubin in the blood. Bilirubin levels can be checked via a serum bilirubin (SBR) blood test or a transcutaneous bilirubinometer device, which measures how much of a certain light shines through the skin.
If the infant's jaundice persists for more than 2 weeks, doctors may perform further blood tests and urine tests to check for underlying disorders. However, in breast-fed babies who are otherwise well and feeding and gaining weight appropriately, this can be normal.
Treatments for infant jaundice
Phototherapy, pictured here, is a treatment for cases of infant jaundice that do not resolve on their own.
Typically, treatment for mild jaundice in infants is unnecessary, as it tends to disappear on its own within 2 weeks.
If the infant has severe jaundice, they may need to be readmitted to the hospital for treatment to lower levels of bilirubin in the bloodstream. In some less severe cases, treatment may be done at home.
Some treatment options for severe jaundice include:
- Phototherapy (light therapy) - treatment by light rays. The baby is put under a special light, covered by a plastic shield to filter out ultraviolet light. The light manipulates the structure of bilirubin molecules so they can be excreted.
- Exchange blood transfusion - the baby's blood is repeatedly withdrawn and then replaced (exchanged) with donor blood. This procedure will only be considered if phototherapy does not work because the baby would need to be in an intensive care unit (ICU) for newborns.
- Intravenous immunoglobulin (IVIg) - in cases of rhesus or ABO incompatibility, the infant may have a transfusion of immunoglobulin; this is a protein in the blood that lowers the levels of antibodies from the mother, which are attacking the infant's red blood cells.
If jaundice is caused by something else, surgery or drug treatment may be required.
Potential complications of infant jaundice
- Acute bilirubin encephalopathy - a condition caused by a build-up of bilirubin in the brain (bilirubin is toxic to brain cells). Signs of acute bilirubin encephalopathy in a baby with jaundice include fever, sluggishness, high-pitched crying, poor feeding, and arching of the body or neck. Immediate treatment may prevent further damage.
- Kernicterus (nuclear jaundice) - a potentially fatal syndrome that occurs if acute bilirubin encephalopathy causes permanent brain damage.
Prevention of infant jaundice
The best way of reduce chances of an infant developing jaundice is to make sure they are well fed. For the first week or so of life, breast-fed babies should be fed 8-12 times a day, while formula-fed babies should be fed 1-2 ounces of formula every 2-3 hours.