Haematology 

What is Neonatal Alloimmune Thromobocytopenia (NAIT)?

NAIT stands for Neonatal Alloimmune Thrombocytopenia. In short, NAIT is a severe blood platelet deficiency in the foetus and newborn. Humans need a platelet count of

150-400 x 10 9/L to be healthy. The platelet count of NAIT babies is very low.

Why are blood platelets important to my baby?

Platelets allow blood to clot. When there are not enough platelets, or the platelets are not functioning correctly, any provoked bleeding will last much longer than normal (hemorrhage) and may cause permanent damage.

What causes NAIT?

NAIT is caused by a mismatch between mother and baby’s platelet types. The mother’s body recognizes the baby’s platelet types as ‘foreign’. The mother then tries to protect herself by forming proteins, called antibodies. These antibodies the mother has formed are designed to destroy as many ‘foreign’ platelets as possible.

What are the risks to my baby?

Without treatment during your pregnancy there is a risk that your unborn child may develop extremely low platelets. It is possible that the foetus may haemorrhage (most commonly in the brain, spinal cord or abdomen). This can occur during pregnancy, delivery, or soon following birth.

Is there treatment for NAIT affected pregnancies?

Treatment plans vary, but generally include a choice between weekly IVIG (intravenous immunoglobulin) infusions, prednisolone, and very rarely a combination of the two treatments. In some cases you may also be offered foetal platelet transfusions.

In severe cases your doctor may recommend a caesarean section for your baby, usually around 34-36 weeks gestation.

What is IVIG?

The treatment most commonly used in NAIT is intravenous immunoglobulin (IVIG). This is plasma product containing antibodies which is given into a vein, usually in your arm, through a drip (intravenously). Antibodies are produced by white blood cells, to fight infections. IVIG is a human blood product, which means that the antibodies have been collected from numerous blood donors.

This means that if you receive IVIG you will never be able to donate blood in the UK, even when your low platelets have recovered.

IVIG is given as an infusion (liquid mixture) through a drip over a few hours.

These infusions will usually be given once a week from when you reach 28 weeks into your pregnancy.

Handy Tips

  • These infusions can often take several hours. Make sure you are prepared with snacks and drinks.

  • These infusions can often give headaches we would recommend taking 1g of oral paracetamol prior to receiving your infusion each time.

Will there be complications with future pregnancies?

Your doctor will order blood tests for yourself and your child’s father, which will determine the likelihood of having subsequent NAIT affected pregnancies. You will either have a one hundred percent or fifty percent chance of subsequent pregnancies being affected. The test is called Platelet Antigen Genotyping.

How rare is NAIT? Why was it not detected sooner?

Currently there is no prenatal testing for NAIT, which is why it is not possible to diagnose it during pregnancies. NAIT is estimated to occur in one in every 800 live births, but a lot of mild cases remain undetected.

This is all very overwhelming and confusing, where can I find someone to talk to?

There is very little reliable information regarding NAIT available. However a group of parents who have had to deal with the issues of NAIT decided to do something to try and raise awareness of this under diagnosed and often misdiagnosed condition, so have created a website, naitbabies.org, and can put parents in contact with others in support groups.

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Further information

For further information please contact below

 

Haematology Liverpool

Contact Details: 0151 706 3397

Text phone number:  18001 0151 706 3397

 

Author: Haematology Liverpool

Review date: April 2029

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