What is Breast Milk Jaundice?
Jaundice, also referred to as hyperbilirubinemia, is a common condition among newborns, affecting 60-80% of all healthy full-term and late-term babies. Typically, it is defined by high levels of bilirubin – a yellow substance produced during the normal breakdown of red blood cells – in the baby’s blood. When these levels become high enough, the skin and whites of the baby’s eyes can turn yellow, a condition known as jaundice.
This condition is more frequent in babies who are breastfed compared to those who are formula-fed. This happens usually due to two reasons commonly known as “breastfeeding jaundice” and “breast milk jaundice”.
“Breast milk jaundice” was first recognized in 1963. It was observed that some breastfed babies had high levels of unconjugated bilirubin, a variant of the yellow substance, that lasted beyond the baby’s third week of life. This usually begins during the baby’s first or second week and tends to resolve on its own even if you continue nursing your baby, which can last up to 8-12 weeks.
Babies with “breast milk jaundice” often have higher peaks of bilirubin in their blood and take longer to recover compared to babies with high bilirubin levels caused by other factors. Before diagnosing a baby with “breast milk jaundice,” other possible causes of high bilirubin levels must be ruled out.
What Causes Breast Milk Jaundice?
The exact cause of breast milk jaundice, a condition that causes newborn’s skin and eyes to turn yellow, isn’t completely understood. However, there are theories that suggest it could be related to certain factors in human breast milk, or possibly certain genetic mutations in the babies affected by it.
Various elements found in breast milk could contribute to breast milk jaundice. These include pregnane-3a,20ß-diol, interleukin IL1ß, ß-glucuronidase, epidermal growth factor, and alpha-fetoprotein. Pregnane-3a,20ß-diol is thought to interfere with the process that helps remove a yellow pigment called bilirubin from the body, leading to its buildup. ß-glucuronidase, an enzyme naturally found in the body, is believed to increase the body’s reabsorption of bilirubin, rather than removing it. Interestingly, ß-glucuronidase is found in larger quantities in breast milk compared to formula milk.
Additionally, interleukin IL1ß may have an effect that leads to an excess of bilirubin. The epidermal growth factor, which is found in higher amounts in breast milk and in babies who are exclusively breastfed, is thought to increase the absorption of bilirubin and slow down intestine movement, resulting in higher levels of unconjugated bilirubin. Babies with breast milk jaundice often have higher levels of alpha-fetoprotein in their blood, but the exact reason for this is not yet known.
Research has suggested that certain genetic mutations, particularly in a gene called UGT1A1, could increase the likelihood of developing breast milk jaundice. The same gene has also been linked to Crigler-Najjar and Gilbert syndrome, two conditions that result in prolonged increased levels of bilirubin.
Risk Factors and Frequency for Breast Milk Jaundice
In the United States, breast milk jaundice affects approximately 20 to 30% of newborns who are primarily breastfed. Between 30 to 40% of these infants may have bilirubin levels of 5 mg/dL or more. About 2 to 4% of babies who are exclusively breastfed can have bilirubin levels above 10 mg/dL by their third week of life. Furthermore, studies conducted in other countries, like Turkey and Taiwan, highlighted that 20 to 28% of newborns had breast milk jaundice by four weeks, with total serum bilirubin levels also being 5 mg/dL or higher. Although exact global figures are not extensively recorded, it’s anticipated to mirror the prevalence in the United States. Importantly, no evidence indicates that this condition is more common in either sex.
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Breast milk jaundice affects about 20 to 30% of mostly breastfed newborns in the United States.
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30 to 40% of these infants may have bilirubin levels of 5 mg/dL or more.
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About 2 to 4% of exclusively breastfed babies can have bilirubin levels above 10 mg/dL by their third week of life.
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International studies, such as those from Turkey and Taiwan, have found that 20 to 28% of newborns had breast milk jaundice by four weeks.
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The global prevalence of breast milk jaundice is expected to be similar to that in the United States.
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No evidence suggests a higher incidence of this condition based on sex.
Signs and Symptoms of Breast Milk Jaundice
Breast milk jaundice is a condition that may affect healthy infants who are primarily breastfed. It typically occurs within the first two weeks after birth. These infants usually gain weight normally and produce the expected amount of urine and stools. The condition involves an elevated level of a substance called bilirubin in the blood, which should be above 1.5 mg/dL. However, most infants won’t look yellow—commonly referred to as jaundiced—unless this level is above 5 mg/dL. If an infant does show signs of jaundice, the yellowish change in their skin and/or whites of their eyes usually starts in the face before moving to the body and limbs.
Testing for Breast Milk Jaundice
If a patient has hyperbilirubinemia, which means high levels of a substance called bilirubin in the blood, they need to be thoroughly examined to rule out serious causes before diagnosing breast milk jaundice. This check-up involves measuring both unconjugated and conjugated bilirubin levels. If the conjugated bilirubin levels are higher than 1 mg/dL or make up 20% or more of the total bilirubin level, it might indicate conjugated hyperbilirubinemia. This is a condition also known as cholestasis or direct hyperbilirubinemia. When cholestasis is suspected, the patient might be checked for conditions such as biliary atresia, neonatal hepatitis, and other bilirubin excretion disorders.
Both breast milk jaundice and certain types of anemia, known as hemolytic anemias, can cause elevated unconjugated bilirubin levels. Hemolytic causes for hyperbilirubinemia can include blood group incompatibility (known as ABO incompatibility), G6PD deficiency, hereditary spherocytosis, and other instances where antibodies destroy red blood cells. When assessing hemolysis, medical staff often conduct a direct Coombs’ test and measure levels of hemoglobin, hematocrit, and reticulocyte (a type of immature red blood cells). They may also look at a sample of the patient’s blood under a microscope and carry out genetic testing.
In cases of ongoing hyperbilirubinemia, doctors may think about other non-hemolytic causes such as Crigler-Najjar or Gilbert syndrome. However, they generally only investigate these if jaundice lasts longer than is typically seen with breast milk jaundice. Other conditions such as galactosemia and hypothyroidism can also cause unconjugated hyperbilirubinemia. Therefore, these conditions should also be ruled out.
Treatment Options for Breast Milk Jaundice
Breast milk jaundice usually doesn’t require treatment unless the baby’s total bilirubin level (a yellow substance found in blood) is higher than the safety guidelines given by the American Academy of Pediatrics (AAP).
The first step to manage high bilirubin levels is something called phototherapy. This uses light to change bilirubin molecules into a form that can be removed from the body more easily.
If the total bilirubin level stays less than 12 mg/dL, the advice is to keep breastfeeding the baby. If the bilirubin level is slightly elevated (above 12 mg/dL but not high enough to need phototherapy), and there are no signs of the baby’s body breaking down red blood cells too fast (known as hemolysis), then the guidance is still to continue breastfeeding.
In cases where the bilirubin level is higher than 20, it might be beneficial to stop breastfeeding for a short time, about a day, but this is typically only recommended under guidance from a healthcare professional.
What else can Breast Milk Jaundice be?
When a newborn has breast milk jaundice, doctors need to consider other conditions that might be causing the baby’s yellow skin and eye color. These conditions can include:
- Normal newborn jaundice, which is common and usually harmless
- Jaundice caused by red blood cells breaking down too fast (related to blood type incompatibility, G6PD deficiency, hereditary spherocytosis, among others)
- Jaundice due to breastfeeding issues, like not getting enough milk, which can lead to dehydration
- Genetic conditions that affect the body’s ability to break down bilirubin, such as Crigler-Najjar syndrome, pyruvate kinase deficiency, and Gilbert’s syndrome
- A blockage in the liver or bile ducts, which can be caused by conditions like biliary atresia, newborn hepatitis, a cyst in the bile duct, or disorders that affect the way the body gets rid of bilirubin
Jaundice can also be a sign of other illnesses, so it’s important for doctors to consider all possibilities and conduct the right tests.
What to expect with Breast Milk Jaundice
In general, babies with breast milk jaundice have an outstanding outlook. This is because it’s a condition that naturally improves and typically goes away when they are around 12 weeks old.
Possible Complications When Diagnosed with Breast Milk Jaundice
The main concern with neonatal hyperbilirubinemia, which includes breast milk jaundice, is acute bilirubin encephalopathy immediately and something called kernicterus (which is long-term bilirubin encephalopathy) down the line. Why? Because these conditions can potentially leave lasting effects on a baby’s mental and physical development. Thankfully, this is a pretty scarce complication when it comes to breast milk jaundice. In fact, it happens in less than 2% of breastfed babies who show no signs of hemolytic anemia.
Preventing Breast Milk Jaundice
Parents with babies experiencing breast milk jaundice should be informed about what it is and what to expect as it runs its course. Unless advised differently by a healthcare professional, mothers of babies with this condition should continue to breastfeed.
