Antiphospholipid syndrome (APS)
Are you a clinician? See the clinical version of this page.
- Low-dose aspirin plus a heparin injection is the core treatment for obstetric APS.
- Avoid contraceptives containing estrogen if you have antiphospholipid antibodies.
What to know
Will APS affect the pregnancy?
APS can raise the risk of miscarriage, pre-eclampsia, growth problems, and, less often, stillbirth. Treatment lowers these risks. Your live-birth chances depend a lot on your exact antibody pattern and whether you have had a blood clot before. In one large study of treated primary APS pregnancies, live births ranged from about 3 in 10 with the highest-risk pattern (all three antibodies positive) to about 8 in 10 with the lowest-risk pattern (lupus anticoagulant alone). Ask your team which pattern applies to you.
Treatment in pregnancy
Most people with obstetric APS take low-dose aspirin plus a daily blood-thinning injection (heparin). If you have had a blood clot before, you will usually be on a full anticoagulation dose.
Planning ahead
Before pregnancy your team confirms your antibody pattern and history and sets your aspirin and heparin plan. If you take warfarin, it is switched to injections.
If standard treatment is not enough
If problems continue despite aspirin and heparin, your team may add hydroxychloroquine. Adding a steroid (prednisone) to aspirin and heparin is specifically not recommended.
Monitoring in pregnancy
You will have extra checks on blood pressure and the baby's growth, with ultrasounds of blood flow to the placenta.
After birth
The weeks after birth carry a higher clot risk, so blood-thinning is usually continued for a while. Some contraceptives that contain estrogen are avoided.
The numbers, in plain terms
About 80 in 100 (lupus anticoagulant alone)
In one large study of treated primary APS pregnancies, about 80 in 100 women whose only positive test was lupus anticoagulant had a live birth. This is the lowest-risk antibody pattern.
About 30 in 100 (all three antibodies positive)
In the same study, about 30 in 100 women who tested positive for all three antibodies (triple-positive) had a live birth, even with treatment. This is the highest-risk pattern and is worth close specialist planning. These figures come from one retrospective study; your own team can tell you what applies to you.
When to call your team
- Signs of a blood clot: a swollen, painful calf, or sudden chest pain or breathlessness (seek urgent care).
- Severe headache, vision changes, or swelling (possible pre-eclampsia).
- Reduced baby movements, or any bleeding.