From the Research
Aspirin for the prevention of recurrent spontaneous abortion should be administered as early as possible in pregnancy, ideally before 16 weeks of gestation, and continued until 36 weeks of gestation, as supported by the most recent and highest quality study 1.
Key Considerations
- The most recent study 1 suggests that aspirin alone may not be sufficient for improving live birth rates in women with antiphospholipid syndrome, but combining it with heparin therapy can significantly improve pregnancy outcomes.
- The mechanism of aspirin's beneficial effects involves its antiplatelet properties, which improve placental blood flow by inhibiting thromboxane synthesis while preserving prostacyclin production.
- Patients should be informed that aspirin is generally well-tolerated during pregnancy at low doses and should be taken with food to minimize gastrointestinal side effects.
Administration Guidelines
- Low-dose aspirin (81-100 mg daily) should be started preconceptionally or as early as possible in pregnancy.
- The medication should be continued until 36 weeks of gestation.
- For women with recurrent pregnancy loss associated with antiphospholipid syndrome, aspirin is typically combined with heparin therapy.
Evidence Summary
- A meta-analysis of randomized controlled trials 1 found that aspirin plus heparin or heparin alone significantly improved live birth rates in women with antiphospholipid syndrome and recurrent spontaneous abortion.
- Earlier studies 2, 3, 4, 5 also support the use of aspirin in improving pregnancy outcomes, but the most recent study 1 provides the strongest evidence for the administration of aspirin in this context.