Erythroblastosis Fetalis

Overview

Erythroblastosis fetalis — also called haemolytic disease of the newborn, or HDN — is a blood problem that can affect a baby during pregnancy and in the first days after birth. It happens when a mother's immune system makes antibodies (disease-fighting proteins) that attack her baby's red blood cells. Red blood cells carry oxygen around the body. If too many are destroyed, the baby can become anaemic (short of healthy red blood cells), and may develop yellowing of the skin (jaundice) or, in serious cases, swelling. It sounds frightening, but this condition is well understood, it can usually be prevented, and most babies who do get it are treated successfully.

It used to be a common cause of serious illness in newborns. Today it is uncommon in countries with good antenatal care, because blood type testing and preventive injections are offered to every pregnant woman. Mild ABO-type mismatch is more common but usually very mild.

It only affects unborn babies and newborns. The most common situation is a mother who is Rh negative carrying a baby who is Rh positive (the baby inherits the Rh protein from the father). A milder form can happen when a mother has blood group O and her baby has group A or B. Risk can rise with each pregnancy if preventive treatment is not given.

Symptoms

Common symptoms

• Yellowing of the skin and the whites of the eyes (jaundice), especially in the first 24 hours after birth
• Pale skin, lips or nail beds
• Being very sleepy, floppy, or feeding poorly
• A liver or spleen that feels larger than expected
• Fast heartbeat or fast, laboured breathing
• Swelling of the face, body or limbs (called oedema), or puffiness around the eyes
• Many babies have no signs at all and are picked up by blood tests

Symptoms in children

• This condition shows up in the newborn period, so the signs to watch for in a baby are the ones listed above.
• Jaundice that spreads down to the arms, legs, hands or feet
• A baby who is too sleepy to feed, or who has fewer wet nappies than usual
• A baby who is hard to wake or feels floppy when picked up
• Older children are not affected by this condition

Symptoms in older adults

• Erythroblastosis fetalis does not happen in older adults. It only affects a baby before birth and in the first days of life.
• An adult can carry the blood type (Rh negative) that matters for future pregnancies, but adults do not become ill with this condition themselves.

Causes

Main causes

• Rh mismatch: a mother who is Rh negative carries a baby who is Rh positive. If some of the baby's blood gets into the mother's bloodstream — often at birth, or during a miscarriage, bleeding or a procedure in pregnancy — her immune system can start making antibodies against Rh-positive blood. In a later pregnancy, those antibodies can cross the placenta and attack an Rh-positive baby's red blood cells.
• ABO mismatch: most often a mother with blood group O and a baby with group A or B. This is common and usually mild.
• Rarer blood group mismatches, such as Kell.

Risk factors

• The mother is Rh negative and the baby's father is Rh positive
• A previous pregnancy, miscarriage, ectopic pregnancy or termination where the preventive injection was not given
• Bleeding in pregnancy, or procedures such as amniocentesis
• A fall or injury to the abdomen during pregnancy
• Antibodies already found on a blood test in this or an earlier pregnancy

When to see a doctor

See a doctor urgently if:

• Any baby with jaundice in the first 24 hours after birth — get medical help the same day
• A baby who is very sleepy, feeding poorly, or looks pale
• Fewer baby movements than usual during pregnancy
• Vaginal bleeding, fluid leaking, or a fall or knock to the bump during pregnancy

Book a routine appointment if:

• At your first antenatal appointment, when your blood group and antibodies are checked
• Around 28 weeks of pregnancy, to talk about the preventive injection if you are Rh negative
• After birth, if your baby needs a blood test for jaundice or anaemia
• Before a future pregnancy if you already know you have antibodies — ask for an early referral

Diagnosis

During pregnancy, this condition is looked for with routine blood tests and ultrasound scans. After birth, the baby is examined and may have blood tests to check the red blood cell count and the level of bilirubin (the yellow pigment that causes jaundice).

Tests that may be done

• Blood group and antibody screen for the mother at the first antenatal visit and again around 28 weeks
• Repeat antibody level checks during pregnancy if antibodies are found
• Ultrasound scans to check the baby's growth and the fluid around the baby
• A special ultrasound that measures blood flow in a vessel in the baby's brain (called a middle cerebral artery Doppler) to see whether the baby might be anaemic
• A blood sample from the umbilical cord at birth, or a heel-prick blood test, to check the blood count and bilirubin level
• Rarely, amniocentesis (a small sample of the fluid around the baby), only within specialist care

What to expect at your appointment

If you are Rh negative or have antibodies, you will usually be seen more often by your midwife and a specialist team, and you may have extra scans. These tests are quick and do not hurt your baby. Your team will explain each result and what it means for your pregnancy, so ask as many questions as you like.

Treatment

Treatment depends on how mild or serious the condition is. Many babies need only careful monitoring. Some need light therapy for jaundice, and a small number need a blood transfusion. The aim is always to keep the baby safe and well until they can make enough of their own healthy red blood cells.

Self-care at home

• Feed your baby often — regular feeding helps the body clear bilirubin
• Check your baby's skin colour in good daylight, and keep an eye on how many nappies they wet
• Go to all follow-up appointments for blood tests
• Rest when you can and accept help — new-baby tiredness is real
• Never feel shy about calling your midwife, health visitor or GP with a worry

Medical treatments

Your baby's blood counts and bilirubin levels may be checked with blood tests. If jaundice needs treating, babies are placed under special lights (phototherapy), which helps break down bilirubin; it does not hurt, and babies often sleep through it. If a baby is very anaemic, a blood transfusion can be given — sometimes before birth in a specialist centre, or after birth. Occasionally an early delivery is planned so a baby can be treated sooner. For mothers, routine care includes a preventive injection in pregnancy and again after birth if the baby is Rh positive; this is the single most effective way to stop the condition happening in the first place.

When is surgery considered?

Surgery is not normally needed for this condition. In specialist centres, a doctor may carry out a procedure before birth to give a blood transfusion through the umbilical cord, but this only happens in a small number of serious cases.

Living with this condition

Once treatment is finished and blood tests are normal, most families settle back into ordinary baby life. Some babies have a follow-up blood test a few weeks later to check for anaemia that can appear slightly later. If you carry antibodies, you will be offered extra checks in any future pregnancy, starting early on.

Lifestyle tips

• Plan any future pregnancy with your GP or midwife so screening can start early
• Keep your maternity notes and mention your blood group and antibody status at every new appointment
• Do not skip your postnatal check
• Ask about the preventive injection if you have a miscarriage, an ectopic pregnancy or bleeding in pregnancy

Diet and exercise

There is no special diet or exercise that prevents or treats this condition. If you are pregnant, eat normally and stay active as your midwife advises. If your baby is being treated, keep feeding them as usual — feeding helps the body get rid of bilirubin.

Mental health and emotional wellbeing

It is completely understandable to feel anxious, especially if you have been told you carry antibodies, or if a previous baby was affected. Many parents worry throughout the pregnancy, and that is a normal reaction to something that feels out of your control. Talk to your midwife or GP — they can arrange extra support or counselling. If you ever feel unable to cope, or have thoughts of harming yourself, contact your local crisis line or your local emergency number straight away.

Prevention

Yes — in most cases. Routine antenatal care is very good at preventing it. If you are Rh negative, you will be offered a preventive injection of antibodies during pregnancy and again shortly after birth if your baby is Rh positive. The same injection is offered after miscarriage, ectopic pregnancy, or certain tests and procedures in pregnancy. It works by stopping your immune system from making the antibodies that could harm a future baby.

Vaccines

There is no vaccine for this condition. Prevention relies on blood group testing and the preventive antibody injection.

Screening programmes

All pregnant women in the UK are offered blood group and antibody testing at their first antenatal appointment and again around 28 weeks. If antibodies are found, you will be monitored more closely, with extra scans and blood tests.

Complications

If left untreated

• Anaemia — too few red blood cells, which can cause paleness, tiredness and poor feeding
• Severe jaundice, which if very high and untreated can damage the brain (a condition called kernicterus)
• Hydrops fetalis — a serious build-up of fluid and swelling in the baby
• Strain on the heart and breathing difficulties
• In the most severe untreated cases, loss of the baby — which is exactly why screening and monitoring matter so much

Long-term outlook

The outlook today is very good. With routine screening and treatment, most babies recover fully with no lasting effects, and many need nothing more than monitoring. Even babies who need a transfusion usually do very well and go home as normal newborns. If you have worries about your own results, talk them through with your team — they can tell you exactly what your tests mean for you and your baby.

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