Antiphospholipid Syndrome (APS) – How it affects you and your pregnancy

Antiphospholipid syndrome (APS) is an immune system disorder that can cause problems in pregnancy – including an increased risk of having a miscarriage.

If you have APS when you’re pregnant then you will need extra medical care, but treatment will help to reduce the risks to you and your baby.

Here’s our guide to the condition and what you need to know about APS in pregnancy...

What is antiphospholipid syndrome?

Antiphospholipid syndrome (also known as APS, APS syndrome, or Hughes syndrome) is an immune system disorder that leaves you more at risk from blood clots.

In turn that means you are more likely to develop serious conditions like deep vein thrombosis, blood clots in the brain, and arterial clots that could cause a stroke or heart attack.  It can affect anyone at any age but is more common amongst women than men. 

What causes antiphospholipid syndrome (APS)?

Normally, your immune system produces antibodies that protect your body from illness and infections by attacking bacteria and viruses. But when you have APS, your immune system produces abnormal antibodies - called antiphospholipid antibodies - that instead attack proteins that surround cells in your blood and blood vessels. This makes your blood more likely to clot – although it’s not known why.

It's also not clear what causes the immune system to behave in this way. But environmental, genetic and hormonal factors are all likely to play a role in the development of APS.

Can antiphospholipid syndrome (APS) be treated?

APS can’t be cured, but after it has been diagnosed there are treatments that can greatly reduce your chances of developing a blood clot. You will be prescribed an anticoagulant medicine, which prevents blood from clotting. (These are sometimes called blood thinning medications, although they don’t actually make your blood thinner).

What are the symptoms of antiphospholipid syndrome (APS)?

If you have had repeated miscarriages it may be a sign of APS. If you have the condition lupus you are more likely to have APS. Other symptoms you might experience, especially if you have lupus, include rashes, migraine, joint pains and fatigue.

How is antiphospholipid syndrome (APS) diagnosed?

Diagnosis is based around blood tests – to see if antiphospholipid antibodies are present - and an assessment of your medical history and records. 

APS can only be diagnosed after two abnormal blood test results, with at least a 3-month period in between. 

If you test positive for antiphospholipid syndrome, your records will then be checked to see if you’ve had symptoms that could be caused by APS. 

What should I do if I have APS and want to get pregnant?

You should see your GP before you stop using contraception, so that you can talk about a plan for your medication and treatment – to make sure everything is as safe as possible for you and your baby while you’re pregnant.

You should also see a doctor if you have APS symptoms, but have not been diagnosed. 

Will antiphospholipid syndrome affect my pregnancy?

Unfortunately, APS does increase the risk of problems in pregnancy – such as miscarriage, pre-eclampsia, still birth, premature birth and fetal growth issues.  Although this sounds frightening the right treatment and care for the condition greatly reduces the risk of problems occurring. You can also improve your chances of a healthy pregnancy and baby by exercising regularly, not smoking, and eating healthily.

If you have treatment, the chance of having a successful pregnancy is around 80%. It is likely that you will be prescribed aspirin, heparin or both during pregnancy to reduce the likelihood of clots. Warfarin isn’t advised during pregnancy: if you are already on it and become pregnant don’t stop it but do speak to your doctor at once so that it can be changed to a safer alternative.

Will antiphospholipid syndrome (APS) affect my baby?

If you have APS and receive treatment then you’re likely to have a perfectly healthy baby, although birth weight may be low. It’s also possible that antiphospholipid antibodies, which have been passed on by you, will be detected in your baby’s blood. But these usually disappear after six months and don’t cause any problems.

How will my pregnancy care change if I have antiphospholipid syndrome (APS)?

Because APS increases the risk of complications in pregnancy, you will be monitored more carefully throughout your pregnancy. So, a doctor will lead your antenatal care and you will have more scans and checks – such as blood, urine and blood pressure checks, and scans to monitor your baby’s growth and the blood flow being delivered to them through the placenta.