Haemolytic disease of the fetus and newborn (HDFN) can happen when you have a certain blood type (D negative) that's different to your baby's blood type (D positive).

This may mean you have antibodies that can break down your baby's red blood cells.

You might have antibodies if you've come into contact with D positive blood before, for example during:

• a blood transfusion
• a previous pregnancy

Haemolytic disease of the fetus and newborn (HDFN) is routinely screened for during pregnancy. You'll be offered a blood test at your first antenatal appointment at 8 to 12 weeks.

If the results of the blood test show your blood type is:

• D positive, there's no risk of HDFN
• D negative, your baby's blood will be tested too

If the results show your baby’s blood type is:

• D negative, then there's no risk of HDFN
• D positive, you’ll need another test to check if your baby’s at risk of HDFN

If there's a risk of haemolytic disease of the fetus and newborn (HDFN) during pregnancy, you’ll usually be offered injections to stop you developing antibodies.

If these injections do not help and you develop antibodies, then there are extra scans and blood tests to help monitor your baby.

After they're born, your baby will continue to be monitored, to look for signs of  jaundice and anaemia.

Symptoms of jaundice include:

• skin or whites of the eyes turn yellow – on brown or black skin, this is easier to see on the palms of the hands or soles of the feet
• dark yellow urine or pale-coloured poo
• being sleepy, and not wanting to feed or not feeding as well as usual

Symptoms of anaemia include:

• pale skin – on brown or black skin, this is easier to see on the fingernails or the insides of the eyelids
• breathing more quickly than usual
• being sleepy, and not wanting to feed or not feeding as well as usual

Contact your doctor, midwife or health visitor urgently if:

If your baby is diagnosed with haemolytic disease of the fetus and newborn (HDFN), your midwife or doctor will discuss the treatment options with you. They'll explain what will happen, as well as the benefits and risks.

Treatment during pregnancy includes:

• blood transfusions for your baby
• weekly immunoglobin treatments for you, to prevent your baby from getting anaemia

If your baby develops anaemia later on in the pregnancy, you may need to have a C-section before your due date.

Treatment for newborns includes:

• light therapy on your baby's skin for jaundice
• your baby's blood is replaced with donated blood (exchange blood transfusion)

The risk of complications is low because the treatments are usually very effective.

But if your baby is very unwell, they may need to be treated in a neonatal intensive care unit.

• NCT: rhesus negative blood and pregnancy – what you need to know
• NHS Blood and Transplant: receiving anti-D immunoglobulin in pregnancy (pdf, 282KBb)