Can you take Aspirin (ASA) 81mg during pregnancy?

Low-Dose Aspirin During Pregnancy: Indications and Recommendations

Low-dose aspirin (81 mg) is recommended during pregnancy for women at high risk of preeclampsia, starting between 12-16 weeks of gestation and continuing until delivery. This recommendation is supported by multiple clinical guidelines, including those from the American College of Obstetricians and Gynecologists (ACOG) and the US Preventive Services Task Force (USPSTF) 1, 2.

Who Should Take Low-Dose Aspirin During Pregnancy

High-Risk Factors (One factor is sufficient for aspirin recommendation):

• History of preeclampsia
• Multifetal gestation (twins, triplets)
• Chronic hypertension
• Type 1 or 2 diabetes
• Renal disease
• Autoimmune diseases (especially SLE and antiphospholipid syndrome)

Moderate-Risk Factors (Two or more needed for aspirin recommendation):

• First pregnancy (nulliparity)
• Maternal age ≥35 years
• BMI >30 kg/m²
• Family history of preeclampsia (mother or sister)
• Sociodemographic risk factors
• Previous adverse pregnancy outcome

Dosage and Timing

• Dose: 81 mg daily (US recommendation) 3, 4
• When to start: Between 12-16 weeks gestation, optimally before 16 weeks 4, 1
• When to stop: Continue until delivery 4

Special Considerations

For Women with SLE or Antiphospholipid Syndrome

• All SLE patients should take low-dose aspirin (81-100 mg daily) during pregnancy 3
• For obstetric APS: Combine low-dose aspirin with prophylactic-dose heparin/LMWH 3
• For thrombotic APS: Combine low-dose aspirin with therapeutic-dose heparin/LMWH 3
• If possible, SLE patients should also take hydroxychloroquine during pregnancy 3

Safety Considerations

• Low-dose aspirin (≤100 mg daily) is considered safe during pregnancy 5, 6
• No increased risk of placental abruption, postpartum hemorrhage, or fetal intracranial bleeding 4
• Caution: FDA labeling advises against using aspirin during the last 3 months of pregnancy unless specifically directed by a doctor, due to potential complications during delivery 7

Effectiveness

• Reduces preeclampsia risk by approximately 24% in high-risk women 4
• Decreases preterm birth risk by 14% 4
• Lowers intrauterine growth restriction risk by 20% 4

Important Clinical Considerations

Potential Limitations

• Some studies suggest that 81 mg may be insufficient for optimal prevention, with European guidelines recommending 150 mg daily 8, 3
• A study evaluating ACOG's recommendation of 81 mg aspirin for women with chronic hypertension found no significant reduction in superimposed preeclampsia 3
• Effectiveness may vary depending on specific risk factors and when treatment is initiated

Common Pitfalls to Avoid

• Starting aspirin too late (after 16 weeks)
• Discontinuing aspirin too early (before delivery)
• Not identifying all relevant risk factors when assessing patients
• Using aspirin for prevention in low-risk women without indication
• Poor patient education about medication adherence

Algorithm for Decision-Making

1. Assess for high-risk factors (one is sufficient)
2. If no high-risk factors, assess for moderate-risk factors (need two or more)
3. If indicated, prescribe 81 mg aspirin to start between 12-16 weeks
4. Continue daily until delivery
5. For patients with SLE or APS, add appropriate additional medications
6. Monitor for adherence and any adverse effects

Remember that low-dose aspirin is not recommended for prevention of early pregnancy loss, fetal growth restriction, stillbirth, or preterm birth in the absence of preeclampsia risk factors 1.