Low platelets during pregnancy

Around 1 in every 10 people have low platelets (thrombocytes) during their pregnancy.

Most of the time, this doesn't cause problems. Although the likelihood of complications depends on the cause of your low platelet count.

What are platelets?

Platelets are very small cells that are found in your blood. Their role is to prevent bleeding.

When you hurt yourself, your platelets become sticky and clump together to form a blood clot. This stops the bleeding.

If your platelet count is low, you may not have enough platelets in your blood to stop bleeding. This is called 'thrombocytopenia'.

A low platelet count during pregnancy is also known as 'gestational thrombocytopenia'.

You might not have any symptoms of gestational thrombocytopenia. It might be found during routine pregnancy blood tests to monitor your well-being.

If you do have symptoms, you may notice that you have:

• bleeding gums
• skin rash
• small bruises

If your low platelet count is caused by another condition, you may also have:

• hypertension
• kidney failure
• headache
• changed personality

There are many different causes of low platelets during pregnancy.

Gestational thrombocytopenia

Gestational thrombocytopenia is a low platelet count caused by normal changes in pregnancy. It accounts for up to 8 in 10 cases of low platelets during pregnancy.

It's usually mild and goes away after your baby is born. It doesn't usually cause any problems for you or your baby.

Immune thrombocytopenia (ITP)

Immune thrombocytopenia is an autoimmune condition, where your body makes antibodies that destroy your platelets.

It can happen at any time, but it can get worse during pregnancy. It can cause very low platelets. You may need treatment before giving birth.

HELLP syndrome

HELLP syndrome is a severe form of pre-eclampsia and a serious pregnancy complication. It can cause very low platelets, as well as liver problems.

Other causes

Other causes of low platelets can include:

• viruses — such as, HIV, hepatitis C, Epstein-Barr virus and cytomegalovirus
• not having enough vitamin B12 or folate in your diet
• some medicines
• liver disease
• overactive spleen

A low platelet count is diagnosed from a routine blood test called a full blood count (FBC).

Your doctor or midwife will offer you this blood test, as part of your routine antenatal tests. These are done early in pregnancy and again at 26 to 28 weeks.

If your platelets are low, you might have further blood tests to look for the cause.

Your treatment will depend on what's causing your low platelet count.

You'll be offered more full blood count tests to monitor your condition. The frequency of these tests will depend on:

• how low your platelet count is
• your stage of pregnancy

If you have immune thrombocytopenia (ITP), you will be referred to a haematologist (a doctor who specialises in blood problems).

You may be advised to give birth in hospital. This is because you might need a blood transfusion if you lose a lot of blood.

Medicines for platelets during pregnancy

There are several treatments which may help to increase your platelet count, including:

• steroid medicine (prednisolone)
• intravenous immunoglobulin (IVIg) — this is a dose of antibodies given into your vein
• a platelet transfusion

You might be advised to have your labour induced, if your platelet count continues to fall.

Thrombocytopenia can increase your chance of bleeding around your spinal cord. Your doctor or midwife will discuss if an epidural is safe for you.

Other treatment options

In some cases, a splenectomy may be considered.

Gestational thrombocytopenia doesn't usually cause any problems for you or your baby. It's not linked to an higher chance of having a postpartum haemorrhage (more bleeding than normal), or your baby having thrombocytopenia.

If you have immune thrombocytopenia (ITP), there is an increased chance of you or your baby having a haemorrhage. Where possible, your doctor or midwife will try to avoid delivering your baby by assisted delivery.

ITP may affect your baby. Your baby will have a blood test at birth to measure their platelets.

Will my low platelets get better after my baby is born?

It depends on what's causing your low platelet count. If you have gestational thrombocytopenia your platelets should go back to normal after your baby is born.

Your doctor or midwife will recommend that you have a blood test after the birth. They will advise you to have repeat blood tests about 2 and 6 weeks after giving birth. This is to check that your platelets have recovered.

However, if you have immune thrombocytopenia (ITP), your platelets might remain low and need further follow up with a haematologist.

There's no evidence that you can prevent thrombocytopenia. Although there are things you can do to support your health during pregnancy.

If you are concerned about your blood test results, talk to your doctor or midwife.

To learn more about ITP in pregnancy visit the ITP Australia and New Zealand website.