Antiphospholipid syndrome

Also called APS, Hughes syndrome, Sticky blood

An immune condition that makes blood clot too readily. A treatable cause of recurrent miscarriage and of stroke in young people.

What it is

An autoimmune condition in which antibodies make the blood more likely to clot. It causes clots in veins and arteries, and pregnancy complications including recurrent miscarriage and stillbirth.

It matters out of proportion to how well known it is, for two reasons. It is a leading treatable cause of recurrent miscarriage, and treatment with aspirin and heparin transforms live birth rates from poor to good. And it is one of the commonest identifiable causes of stroke in people under 50, where a young stroke with no obvious cause should always prompt testing.

It occurs on its own or alongside another autoimmune condition, most often lupus.

Diagnosis requires blood tests repeated at least 12 weeks apart, because a single positive result can follow an infection and mean nothing. That two-test rule is why diagnosis takes months and why people are sometimes told they have it on inadequate evidence.

Treatment is usually lifelong anticoagulation after a clot, and aspirin plus heparin during pregnancy. Getting the right anticoagulant matters: the newer direct oral anticoagulants are less effective than warfarin in some people with this condition, which is a genuine and under-appreciated safety point.

Signs you might notice

A blood clot in a leg or lung: a swollen painful calf, or sudden breathlessness and chest pain. See deep vein thrombosis and pulmonary embolism.

Stroke or transient ischaemic attack, particularly under 50.

Recurrent miscarriage, especially after 10 weeks, or a stillbirth, or severe early pre-eclampsia.

A lacy, blotchy purple-red pattern on the skin, most often on the arms and legs, that does not fade with warmth.

Migraine-like headaches, memory difficulty, and unexplained low platelet counts.

999: symptoms of stroke, using the FAST test, or sudden breathlessness and chest pain.

How it can affect day-to-day life

Living on anticoagulation shapes ordinary life: bleeding risk, telling every dentist and surgeon, care with contact sport, and never stopping without advice.

Warfarin means regular blood tests and attention to diet and interacting medicines, which many people manage well with a self-testing meter.

Pregnancy with APS is closely monitored, involves daily heparin injections, and is usually successful with treatment. The contrast with a previous history of repeated loss is enormous, and so is the anxiety.

Combined hormonal contraception and standard HRT raise clot risk further and generally need avoiding or specialist advice.

Fatigue and cognitive difficulty are common, real, and rarely addressed.

Supporting someone well

After two or three miscarriages, or one late loss, ask specifically for antiphospholipid antibody testing. It is part of recurrent miscarriage investigation and is sometimes skipped.

For a stroke or clot in a young person with no clear cause, ask for it too.

Insist on the confirmatory repeat test 12 weeks later before accepting a diagnosis.

Ask which anticoagulant is right; direct oral anticoagulants are not the correct choice for everybody with this condition.

Plan pregnancy in advance with a specialist obstetric team, not after conceiving.

Never stop anticoagulation without advice, and tell every clinician including the dentist.

Reduce other clot risk: stop smoking, treat blood pressure and cholesterol, move on long journeys.

Where to get help

A GP practice for referral to haematology or rheumatology.

A recurrent miscarriage clinic for pregnancy loss, and a specialist obstetric team before conceiving.

999 for stroke symptoms or sudden breathlessness with chest pain.

LUPUS UK and Thrombosis UK both cover APS and run support services.