Is Aspirin (Asa) recommended for all pregnancies?

Aspirin Use During Pregnancy: Recommendations and Indications

Low-dose aspirin is not recommended for all pregnancies but should be selectively used only in women at high risk for preeclampsia. 1, 2

Indications for Aspirin Use in Pregnancy

• Low-dose aspirin (81 mg/day) is recommended specifically for women at high risk of preeclampsia, not as a universal intervention for all pregnant women 1, 2

• High-risk factors that warrant aspirin prophylaxis include:

  • History of preeclampsia, especially with early onset (<34 weeks) 1, 2
  • Multifetal gestation 1, 2
  • Chronic hypertension 1, 2
  • Type 1 or type 2 diabetes 1, 2
  • Renal disease 1, 2
  • Autoimmune disease (such as systemic lupus erythematosus or antiphospholipid syndrome) 1, 2

• Aspirin prophylaxis should also be considered in women with more than one moderate risk factor:

  • First pregnancy (nulliparity) 1, 2
  • Maternal age ≥35 years 1, 2
  • BMI >30 kg/m² 1, 2
  • Family history of preeclampsia 1, 2

Timing and Dosage

• When indicated, low-dose aspirin should be initiated between 12 and 28 weeks of gestation, optimally before 16 weeks 1, 2
• The recommended dose is 81 mg daily 1, 2
• Aspirin should be continued until delivery when used for preeclampsia prevention 1, 2
• Some evidence suggests that bedtime administration may be more effective than morning dosing 3

Safety Considerations

• Low-dose aspirin (≤100 mg daily) is considered safe during pregnancy when used for appropriate indications 4
• The FDA label cautions that aspirin use during the last 3 months of pregnancy should be avoided unless specifically directed by a doctor, as it may cause problems in the unborn child or complications during delivery 5
• There is no increased risk of congenital abnormalities associated with low-dose aspirin use in pregnancy 1, 2

Conditions Where Aspirin Is Not Recommended

• In the absence of high-risk factors for preeclampsia, aspirin is not recommended for:
  • Prevention of early pregnancy loss 1, 2
  • Prevention of fetal growth restriction in low-risk women 1, 2
  • Prevention of stillbirth in low-risk women 1, 2
  • Prevention of preterm birth in low-risk women 1, 2

Special Populations

• In pregnant women with mechanical heart valves, low-dose aspirin (75-100 mg) is recommended during the second and third trimesters in addition to anticoagulation therapy 6
• For pregnant women with myeloproliferative neoplasms, aspirin may be indicated as part of disease management 6
• In pregnant women with inflammatory bowel disease, aspirin is not routinely recommended unless there are other indications 6

Potential Pitfalls

• Initiating aspirin too late in pregnancy (after 16 weeks) may reduce its effectiveness in preventing preeclampsia 7
• Discontinuing aspirin before delivery in high-risk women may increase risk of complications 1, 2
• Using doses higher than recommended (>100 mg daily) may increase risk of maternal or fetal complications 4

Remember that aspirin therapy during pregnancy should always be prescribed and monitored by healthcare providers based on individual risk assessment rather than used universally for all pregnancies.