Newborn jaundice

Jaundice is a yellow colour in the skin and in the whites of the eyes. It appears when bilirubin, a yellow substance made when red blood cells are broken down and normally cleared by the liver, builds up in the blood.

A newborn makes a lot of bilirubin and the liver takes a few days to become efficient at removing it, so jaundice is common in the first week of life and commoner still in babies born before 37 weeks. In most babies it appears around the second or third day, peaks, and fades within about two weeks.

The yellow usually starts on the face and head and spreads down the body. Check in bright daylight, and look at the whites of the eyes, the gums and the inside of the mouth, and the palms and soles. Pressing gently on the nose or forehead and then letting go makes the colour easier to see. On darker skin the yellow is harder to notice, so the eyes and gums matter most.

Other things to watch are dark urine, which should be colourless in a newborn, and pale chalky stools instead of the usual yellow or greenish ones. A baby who is very sleepy, hard to wake, floppy, not feeding, or having fewer wet nappies needs to be seen whatever the colour looks like.

See a doctor within a day or two if the yellow is deepening rather than fading, if it is still there after two weeks in a term baby or three weeks in a premature baby, if the stools are pale and chalky or the urine dark, if the palms and soles look yellow, or if weight gain is poor.

Most newborn jaundice is simply the liver catching up. This is often called physiological jaundice and needs nothing more than good feeding and watching.

Some jaundice has a cause that needs treating: a difference in blood group between mother and baby, an inherited condition that makes red cells break down faster, infection, bruising from a difficult delivery, prematurity, or an underlying liver or thyroid problem. Jaundice that appears in the first 24 hours, or that goes on for weeks, is more likely to have such a cause. Feeding that is not yet established can also raise bilirubin, and jaundice related to breast milk can linger harmlessly for several weeks.

• Being born before 37 weeks
• A brother or sister who needed treatment for newborn jaundice
• A mother with blood group O, or a rhesus negative mother
• Feeding not yet established, or slow weight gain in the first days
• Bruising or a swelling on the head after delivery
• Infection around the time of birth
• An inherited condition affecting red blood cells

Most babies come to no harm. The concern is a bilirubin level that climbs very high, because bilirubin can then cross into the brain.

• Kernicterus, brain damage caused by a very high bilirubin level
• Cerebral palsy and movement problems
• Hearing loss
• Dehydration and poor weight gain when feeding is not going well
• A missed underlying cause, such as infection or a liver problem

• Feeding often from the start, about 8 to 12 times in 24 hours
• Getting help early if breastfeeding is painful or the baby is not latching
• Having the mother's blood group checked in pregnancy, and anti-D given when it is advised
• Letting the baby be examined for jaundice before discharge and at the newborn check
• Counting wet nappies and weighing the baby in the first week
• Having any yellow colour measured rather than guessed at, especially on darker skin

The level of bilirubin is measured, not estimated by eye. A small meter pressed against the skin gives a reading in seconds, and a blood test from a heel prick gives an exact figure. The result is read against the baby's age in hours and how many weeks the pregnancy reached, to decide whether treatment is needed.

Where the jaundice is early, severe or prolonged, further tests look for a cause: the blood groups of mother and baby, a Coombs test, a full blood count, thyroid tests and tests for infection.

Most babies need no treatment beyond frequent feeding and a repeat check. Feeding matters because bilirubin leaves the body in the stools.

When the level is above the treatment line, phototherapy is used. The baby lies undressed under a blue light, or on a light blanket, with the eyes protected, usually for about two days, and feeds continue throughout. The level is rechecked to see that it is falling.

Very high levels that do not respond need an exchange transfusion, in which the baby's blood is replaced in small amounts, and sometimes immunoglobulin given through a drip when blood groups are the cause. Any underlying problem, such as an infection or a thyroid condition, is treated as well.