Stopping Aspirin at 34 Weeks in Pregnancy
No, aspirin should not be stopped at 34 weeks—it should be continued daily until delivery in pregnant women at high risk for preeclampsia. 1, 2, 3
Primary Recommendation
The American College of Obstetricians and Gynecologists explicitly recommends that low-dose aspirin initiated for preeclampsia prevention should be continued daily until delivery, not stopped at any predetermined gestational age such as 34 weeks. 1, 2, 3 This recommendation is supported by multiple international guidelines from Canada, Ireland, New Zealand, the USA, and the UK. 1
Rationale for Continuation Until Delivery
Persistent Risk Throughout Pregnancy
- Preeclampsia risk persists throughout pregnancy and even into the early postpartum period, with eclamptic seizures potentially developing for the first time after delivery. 1
- Stopping aspirin at 34 weeks removes protection during a high-risk period when preeclampsia can still develop or worsen. 1
- The pathophysiology of preeclampsia involves ongoing endothelial dysfunction that requires continuous aspirin therapy to maintain vascular protection. 4
Safety Profile Through Delivery
- Low-dose aspirin (75-81 mg) does not increase risks of placental abruption, postpartum hemorrhage, fetal intracranial bleeding, or perinatal mortality when continued until delivery. 1, 5, 6
- The safety data specifically supports continuation through the third trimester and delivery. 1, 5
Common Pitfall to Avoid
Do not stop aspirin at 36 weeks (or 34 weeks) "just to be safe"—this practice is not evidence-based and removes protection during a critical high-risk period. 1 The American College of Obstetricians and Gynecologists specifically advises against this common misconception. 1
Important Distinction
- The FDA warning about aspirin in the third trimester refers to high doses (>100 mg), not prophylactic low doses (75-81 mg). 1, 7
- Low-dose aspirin for preeclampsia prevention has a completely different risk-benefit profile than high-dose aspirin used for other indications. 1
Special Circumstance: Planned Cesarean Section
If a planned cesarean section with neuraxial anesthesia is scheduled, aspirin may need to be discontinued 7-10 days before the procedure to allow adequate platelet recovery. 8 However, this is a specific exception requiring:
- Coordination with obstetric anesthesiology 8
- Verification of platelet count >75 × 10⁹/L before spinal anesthesia 8
- Balancing thrombotic risk during the brief discontinuation period 8
For spontaneous labor or vaginal delivery, aspirin should be continued until delivery occurs. 1, 2, 3