Neonatal Jaundice in the first week of birth

Neonatal jaundice or Neonatal hyperbilirubinemia is a yellowing of the skin and other tissues of a newborn infant. A bilirubin level of more than 85 umol/l (5 mg/dL) manifests clinical jaundice in neonates whereas in adults a level of 34 umol/l (2 mg/dL) would look icteric. In newborns jaundice is detected by blanching the skin with digital pressure so that it reveals underlying skin and subcutaneous tissue. Jaundice newborns have an apparent icteric sclera, and yellowing of the face, extending down onto the chest.

In neonates the dermal icterus is first noted in the face and as the bilirubin level rises proceeds caudal to the trunk and then to the extremities.[1]

This condition is common in newborns affecting over half (50 -60%) of all babies in the first week of life.[2]

Notoriously inaccurate rules of thumb have been applied to the physical exam of the jaundiced infant. Some include estimation of serumbilirubin based on appearance. One such rule of thumb includes infants whose jaundice is restricted to the face and part of the trunk above the umbilicus, have the bilirubin less than 204 umol/l (12 mg/dL) (less dangerous level). Infants whose palms and soles are yellow, have serum bilirubin level over 255 umol/l (15 mg/dL) (more serious level).

Studies have shown that trained examiners assessment of levels of jaundice show moderate agreement with icterometer bilirubin measurements.[1]

In infants jaundice can be measured using invasive or non-invasive methods. In non-invasive method Ingram icterometers and Transcutaneous bilirubinometers are used.

Breast feeding jaundice

"Breastfeeding jaundice" or "lack of breastfeeding jaundice," is caused by insufficient breast milk intake,[4] resulting in inadequate quantities of bowel movements to remove bilirubin from the body. This can usually be ameliorated by frequent breastfeeding sessions of sufficient duration to stimulate adequate milk production. Passage of the baby through the vagina during birth helps stimulate milk production in the mother's body, so infants born by cesarean section are at higher risk for this condition[citation needed].

[edit]Breast milk jaundice

Whereas breast feeding jaundice is a mechanical problem, breast milk jaundice is more of a biochemical problem. The term applies to jaundice in a newborn baby on.

  • First, at birth, the gut is sterile, and normal gut flora takes time to establish. The bacteria in the adult gut convert conjugated bilirubin to stercobilinogen which is then oxidized tostercobilin and excreted in the stool. In the absence of sufficient bacteria, the bilirubin is de-conjugated by brush border β-glucuronidase and reabsorbed. This process of re-absorption is called enterohepatic circulation. It has been suggested that bilirubin uptake in the gut (enterohepatic circulation) is increased in breast fed babies, possibly as the result of increased levels of epidermal growth factor (EGF) in breast milk[5] .
  • Second, the breast-milk of some women contains a metabolite of progesterone called 3-alpha-20-beta pregnanediol. This substance inhibits the action of the enzyme uridine diphosphoglucuronic acid (UDPGA) glucuronyl transferase responsible for conjugation and subsequent excretion of bilirubin. In the newborn liver, activity of glucuronyl transferase is only at 0.1-1% of adult levels, so conjugation of bilirubin is already reduced. Further inhibition of bilirubin conjugation leads to increased levels of bilirubin in the blood [6][citation needed]. However, these results have not been supported by subsequent studies. [7]
  • Third, an enzyme in breast milk called lipoprotein lipase produces increased concentration of nonesterified free fatty acids that inhibit hepatic glucuronyl transferase, which again leads to decreased conjugation and subsequent excretion of bilirubin [8][citation needed].

Despite the advantages of breast feeding, there is a strong association of breast feeding with neonatal hyperbilirubinemia and thus risk of kernicterus, though this is uncommon. Serum bilirubin levels may reach as high as 30 mg/dL. Jaundice should be managed either with phototherapy or with exchange blood transfusion as is needed. Breast feeds however need not be discontinued. The child should be kept well hydrated and extra feeds given.