Newborn Jaundice
Why many newborns look yellow in the first week, when it's normal, and the signs that mean your baby needs review.
- Last reviewed
- Sources cited
- 6 sources
- Author
- Dr Jubal John, FRACP
- Category
- medical guides
This page is being reviewed
We’re double-checking this content before publishing it — it’ll be available here shortly.
In the meantime, browse the published guides or contact the rooms.
Take-home
About 60% of term babies (and around 80% of preterm babies) develop clinically apparent jaundice in the first week. Most of the time this is physiological jaundice: a normal transition that passes without treatment. A smaller group needs a blood test (SBR) and sometimes phototherapy to keep their bilirubin safe. Extreme hyperbilirubinaemia (severe enough to need exchange transfusion or carry a meaningful risk of brain injury) is rare — about 9.4 per 100,000 live births (≈ 1 in 10,000). The two questions worth asking are always: how yellow? and how is the baby feeding and waking?
What is jaundice?
Jaundice is the yellow colour of skin and the whites of the eyes caused by bilirubin: a pigment made when old red blood cells are broken down. Newborns make bilirubin faster than adults and clear it more slowly, so levels rise for the first few days.
Visual estimation is unreliable below the waist — rely on a bilirubin measurement against the treatment chart, not your eye, if concerned.
The yellow colour usually starts on the face, then moves down the body. That’s why clinicians check your baby’s face, chest, abdomen, and legs, as a rough guide, the further down the body the yellow reaches, the higher the bilirubin.
Skin-colour checks are a screen, not a diagnosis
Visual assessment alone can miss significant jaundice, especially in babies with darker skin tones. If there is any concern, a transcutaneous meter (a skin probe) or serum bilirubin (SBR) blood test is done. Don’t rely on photos in natural light, check the whites of the eyes and gums.
The three patterns of newborn jaundice
1. Physiological jaundice (the common one)
- Appears after 24 hours of age, peaks around day 3–5
- Term baby, feeding well, passing urine and stool
- Fades by day 10–14 without any treatment
- The baby behaves normally, is alert for feeds, and is gaining weight by day 5–7
2. Breastfeeding / breast-milk jaundice
- Breastfeeding jaundice (week 1): from under-feeding in the first few days. The answer is more effective feeding, not less. A lactation review is often the single most useful step.
- Breast-milk jaundice (week 2+): a benign prolongation that can last 4–8 weeks in otherwise well babies. Continue breastfeeding. A blood test is still needed to confirm the bilirubin is mostly unconjugated and liver function is normal.
3. Pathological jaundice (the one we act on)
Any of these features means the baby needs same-day review and usually a blood test:
Red-flag features of jaundice
- Jaundice in the first 24 hours of life
- A baby who looks deeply yellow: chest, abdomen, or legs yellow, not just face
- A rapid rise in bilirubin (SBR rising > 8.5 µmol/L/hour)
- Jaundice lasting beyond 2 weeks (term) or 3 weeks (preterm)
- Pale stools or dark urine staining the nappy
- A sleepy, poorly-feeding baby, poor weight gain, or weight loss > 10% of birth weight
- Rh or ABO incompatibility, known G6PD deficiency, prematurity, bruising or cephalhaematoma
How jaundice is measured
The threshold for treatment depends on the baby’s age in hours, gestation, and whether they have risk factors for a faster rise. The result is plotted against the Australian/NICE phototherapy nomogram, a single “high” number out of context doesn’t tell the whole story.
Tools used
- Transcutaneous bilirubin (TcB) meter: non-invasive, used for screening in the first days
- Serum bilirubin (SBR) blood test: definitive, required if TcB is elevated or if other red flags are present
- Split bilirubin (conjugated vs unconjugated): requested if jaundice persists beyond 2 weeks to rule out liver or biliary causes
Treatment: usually straightforward
Phototherapy
The standard treatment for high bilirubin is blue-light phototherapy: the baby lies under overhead lights or on a fibre-optic blanket, with eyes protected. Light converts bilirubin in the skin into a form the body clears easily. Most babies need 24–48 hours.
Exchange transfusion
Extremely rarely needed today. Reserved for very high bilirubin levels that don’t respond to intensive phototherapy.
What parents often hear, and what actually helps
What the evidence says
- Sunlight through a window: not recommended. Unreliable, and the heat risk outweighs the benefit.
- Stopping breastfeeding: not recommended in most cases. Adequate, frequent feeding is part of the treatment.
- Water or sugar-water top-ups: not helpful, and risk hyponatraemia. If top-ups are needed, use expressed breast milk or formula.
- Frequent feeds (8–12 per 24 hours): this is the one that helps. Feeds drive stooling, which clears bilirubin.
When to seek help
Green — usually fine
Green: normal
- Mild yellow on face only, appearing after 24 hours, baby feeding and waking well
- Resolving by day 10–14
- Weight gain established by end of week 1
Amber — be alert
Amber: book a review within 24 hours
- Yellow reaching the chest or below by day 3–4
- Jaundice still visible at 2 weeks in a breastfed baby who is otherwise well
- Poor feeding, sleepiness, or fewer than 4 wet nappies per day (once feeding is established)
Red — act now
Red: seek same-day / emergency review
- Jaundice within the first 24 hours of life
- Deep yellow of the whole body, including palms and soles
- Pale, chalky stools and dark urine
- A lethargic baby who is hard to rouse, arches back, has a high-pitched cry, or has seizures
- Significant weight loss > 10% of birth weight
Acute bilirubin encephalopathy is rare but serious
Extreme untreated bilirubin can cross into the brain (kernicterus). Bilirubin encephalopathy occurs at about 0.6 per 100,000 live births, and the permanent injury of kernicterus at about 0.35 per 100,000 (McGillivray et al., APSU surveillance 2010–13), rare because of the thresholds and prompt action, not in spite of them.
Common questions
“My baby looks yellow: do they need a blood test?”
Not always. If the jaundice appears after 24 hours, is limited to the face, and your baby is feeding well, we usually check with a skin meter first. A blood test is done only if the meter is high or there are other concerns.
“Will phototherapy harm my baby?”
No. Short-term side effects are usually minor, a slightly looser stool, mild rash, or temporary separation from mum for feeds. Eye protection is used. Phototherapy has a long safety record when used appropriately.
“Should I stop breastfeeding?”
Almost never. Continue breastfeeding more frequently. If the bilirubin is very high or weight loss is significant, we may add expressed-milk or formula top-ups temporarily, not as a replacement.
“Jaundice is still there at 3 weeks: what now?”
Book a review. Most prolonged jaundice in a thriving breastfed baby is benign breast-milk jaundice, but a split bilirubin test and a look at stool colour are essential to rule out liver conditions such as biliary atresia, where early diagnosis matters enormously.
Related reading
- Breastfeeding support — getting the latch right
- Newborn screening (heel-prick)
- When to seek help
- HealthDirect 1800 022 222
Worried about how yellow your baby looks?
Jaundice is measured, not guessed. If the yellow is deepening or spreading, or your baby is sleepy or feeding poorly, seek review today: a skin-meter or SBR blood test gives an objective level.