ABO haemolytic disease of the newborn: when mother and baby have different blood groups

The NHS describes haemolytic disease of the fetus and newborn (HDFN) as a rare blood disorder where the mother's immune system attacks her baby's blood cells. The better known form is rhesus disease, where a D-negative mother's antibodies attack the blood of a D-positive baby. The NHS jaundice page also lists a baby having a different blood type from their mother as a cause of newborn jaundice.

NICE guidance on newborn jaundice refers to both rhesus haemolytic disease and ABO haemolytic disease. In ABO haemolytic disease it is the ABO blood group difference, rather than the rhesus factor, that matters.

In most babies, the NHS says jaundice is not a sign of another health condition, so ABO haemolytic disease is one of several possible reasons rather than the usual one.

The NHS says the main symptom of jaundice in babies is yellow skin and eyes. You may notice yellow in the whites of the eyes, on the skin, which usually starts on the face and head and can spread, or under the tongue or inside the cheeks. It can be harder to see on black or brown skin. For most babies with jaundice the yellow is most noticeable around 3 days old and usually takes around 2 weeks to go.

NICE advises that jaundice in the first 24 hours of life is an important warning sign and that the baby should have serum bilirubin measured urgently, within 2 hours, and an urgent medical review as soon as possible and within 6 hours to exclude pathological causes. The NHS HDFN page also lists anaemia signs: pale skin, breathing more quickly than usual, and being sleepy and not wanting to feed.

• Yellow skin or whites of the eyes.

• Dark yellow urine or pale-coloured poo.

• Sleepiness and poor feeding.

• Pale skin or fast breathing, which can be signs of anaemia.

The NHS says to ask for an urgent GP or midwife appointment or call NHS 111 if your baby is over 24 hours old and you think they have jaundice, they have been diagnosed with jaundice and it is not getting better or is getting worse, or their pee is dark yellow or brown or their poo is pale and creamy.

It says to call 999 or go to A&E if a baby with jaundice is sleepier than normal or difficult to wake, is not feeding, is floppy or stiff or has jerking or twitching movements, has a high temperature of 38C or more or a low temperature of 36C or less, has no wet nappies, has difficulty breathing, or is less than 24 hours old. It advises not to drive to A&E but to ask someone to drive you or call 999.

The NHS says your baby will be regularly checked for signs of jaundice in the first few days after birth, and if there are signs, bilirubin levels will be measured by blood test or by pressing a special light on the skin. Other tests such as blood tests, pee tests and ultrasound scans of the liver can be used if jaundice could be caused by something serious.

NICE sets thresholds for action by age in hours and says healthcare professionals should interpret bilirubin levels according to the baby's age and manage them using the threshold table and treatment graphs. It advises serum bilirubin measurement in the first 24 hours of life. NICE also notes that several tests, including the cord blood direct antiglobulin test, should not be used to predict significant hyperbilirubinaemia, so a blood group test result alone does not decide management.

The NHS says that if a baby needs treatment for jaundice it is usually phototherapy, shining a special light on the skin, usually in a hospital cot, though sometimes equipment can be used at home. Most babies need around 48 hours. Rarely, a baby may need a blood transfusion or medicine into a vein.

NICE says to use intravenous immunoglobulin (IVIG) as an adjunct to continuous intensified phototherapy in cases of rhesus haemolytic disease or ABO haemolytic disease when the serum bilirubin continues to rise by more than 8.5 micromol/litre per hour. It says parents or carers should be given information on why IVIG is being considered. NICE also says breastfeeding, nappy changing and cuddles can usually continue during treatment, and that mothers of breastfed babies with jaundice should be encouraged to feed frequently and given feeding support.

During phototherapy, NICE says bilirubin should be repeated 4 to 6 hours after starting and every 6 to 12 hours when stable or falling, and that it should be rechecked 12 to 18 hours after stopping to look for rebound, which does not necessarily need a hospital stay.

The NHS says that most babies with jaundice get better without treatment. For HDFN, it says the risk of complications is low because treatments are usually very effective, though a baby who is very unwell may need care in a neonatal intensive care unit. Parents should expect clear explanations from their midwife or doctor about the cause in their own baby and what monitoring is planned.