At what gestational age should a 40-year-old pregnant individual stop taking low-dose Aspirin (Acetylsalicylic Acid) and Calcium supplements?

When to Stop ASA and Calcium in Advanced Maternal Age Pregnancy

Low-dose aspirin should be discontinued at 36 weeks of gestation, while calcium supplementation can be continued until delivery in a 40-year-old pregnant person. 1, 2

Aspirin Discontinuation Timing

Evidence-Based Recommendations

• According to international clinical practice guidelines for pregnancy hypertension, recommendations for when to stop aspirin vary:
  • At 36 weeks (Poland) 1
  • At 36-37 weeks (European Society of Cardiology) 1
  • Not before 37 weeks (SOMANZ) 1
  • Continue until delivery (Canada, Ireland, New Zealand, USA, NICE) 1

However, the FDA drug label specifically warns against using aspirin during the last 3 months of pregnancy unless definitely directed by a doctor, as it may cause problems in the unborn child or complications during delivery 3.

Rationale for 36-Week Discontinuation

The 36-week discontinuation recommendation balances:

1. The preventive benefits of aspirin for preeclampsia
2. The potential increased risk of peripartum bleeding
3. The need to allow adequate time for platelet function to normalize before delivery

Advanced maternal age (40 years) is considered a moderate risk factor for preeclampsia 2, making this timing particularly important to consider.

Calcium Supplementation

Unlike aspirin, calcium supplementation does not affect clotting and has no specific recommendation for discontinuation before delivery. The evidence suggests:

• Calcium supplementation (1-2.5 g/day) is recommended for preeclampsia prevention in women with low calcium intake 1
• There are no guidelines recommending discontinuation of calcium before delivery
• Calcium can be safely continued until delivery

Clinical Algorithm for ASA and Calcium Management

For 40-year-old pregnant person:

1. Low-dose aspirin:

   • Start: Between 12-16 weeks gestation 2
   • Dose: 81 mg daily (USA recommendation) 1, 2
   • Stop: At 36 weeks gestation 1
   • Special consideration: If delivery is anticipated before 36 weeks, aspirin should be discontinued 1 week prior to anticipated delivery 1

2. Calcium supplementation:

   • Start: Early in pregnancy
   • Dose: 1-2.5 g/day (especially if low calcium intake <600 mg/day) 1
   • Continue: Until delivery

Important Considerations

• Advanced maternal age (>35 years) is considered a high-risk pregnancy factor 1
• Aspirin should be discontinued approximately one week before surgical procedures, including planned cesarean section 1
• Stopping aspirin too early may reduce its effectiveness in preventing preeclampsia 2

Potential Pitfalls to Avoid

1. Stopping aspirin too early (before 36 weeks) may reduce protection against preeclampsia
2. Continuing aspirin too close to delivery may increase peripartum bleeding risk
3. Failing to recognize that advanced maternal age (40 years) is itself a risk factor for preeclampsia
4. Not considering the patient's individual risk profile for both preeclampsia and bleeding

Recent evidence from a 2023 randomized clinical trial suggests that aspirin discontinuation as early as 24-28 weeks may be non-inferior to continuation until 36 weeks in selected patients with normal biomarkers 4, but this approach requires specialized testing and is not yet standard practice.