Aspirin Safety During Pregnancy
Low-dose aspirin (81 mg/day) is safe and beneficial during pregnancy for women at high risk for preeclampsia, but regular-dose aspirin should be avoided, especially in the third trimester, unless specifically directed by a doctor. 1, 2
Safety Profile of Aspirin in Pregnancy
Low-Dose Aspirin (≤100 mg/day)
- Safe for targeted use: The USPSTF found adequate evidence that low-dose aspirin use does not increase risks of:
- Placental abruption
- Postpartum hemorrhage
- Fetal intracranial bleeding
- Perinatal mortality 1
- Long-term follow-up data from the CLASP trial showed no differences in physical or mental developmental outcomes in infants at 18 months of age 1
Regular-Dose Aspirin
- Not recommended: FDA labeling specifically warns against using regular-dose aspirin during the last 3 months of pregnancy unless definitely directed by a doctor 2
- Concerns include potential problems in the unborn child and complications during delivery 2
Indications for Low-Dose Aspirin in Pregnancy
Recommended for High-Risk Women
- Women with one or more high-risk factors:
Consider for Moderate-Risk Women
- Women with more than one moderate-risk factor:
Dosing and Timing
- Dose: 81 mg daily (US recommendation) 1, 3, 4
- Initiation: Between 12-28 weeks of gestation, optimally before 16 weeks 3, 4
- Duration: Continue until delivery 3, 4
Benefits of Low-Dose Aspirin
- Reduces risk of preeclampsia by 24% in high-risk women 1, 3
- Reduces risk of preterm birth by 14% 1, 3
- Reduces risk of intrauterine growth restriction by 20% 1, 3
Special Considerations
- SLE patients: The American College of Rheumatology strongly recommends low-dose aspirin (81-100 mg daily) during pregnancy for all SLE patients 1
- Scleroderma renal crisis: Requires special management with ACE inhibitors despite pregnancy risks 1
Clinical Pitfalls to Avoid
- Starting too late: Aspirin should ideally be started before 16 weeks for maximum benefit 3, 5
- Inappropriate use: In the absence of high-risk factors for preeclampsia, evidence does not support prophylactic low-dose aspirin for prevention of early pregnancy loss, fetal growth restriction, stillbirth, or preterm birth 4, 6
- Discontinuing too early: Aspirin should be continued until delivery 3, 4
- Using higher doses: Regular-dose aspirin should be avoided, especially in the third trimester 2
Monitoring
- Women at high risk for preeclampsia should have regular monitoring of blood pressure and assessment for proteinuria throughout pregnancy 3
- Patient education about warning signs requiring immediate medical attention is crucial 3
Remember that while low-dose aspirin is beneficial for specific high-risk populations, it is not recommended for routine use in all pregnant women. The decision to use aspirin should be based on a careful assessment of individual risk factors for preeclampsia.