Can a pregnant woman with placenta lakes take aspirin (acetylsalicylic acid)?

Can Aspirin Be Taken in Pregnancy with Placenta Lakes?

Yes, a pregnant woman with placenta lakes can and should take low-dose aspirin if she has risk factors for preeclampsia, as placenta lakes themselves are not a contraindication to aspirin therapy. 1, 2

Understanding Placenta Lakes and Aspirin Safety

Placenta lakes (also called placental lacunae or intervillous lakes) are blood-filled spaces within the placenta that appear on ultrasound. The critical evidence shows that:

• Low-dose aspirin does not increase the risk of placental abruption, postpartum hemorrhage, or fetal intracranial bleeding in pregnant women, including those with placental abnormalities 1, 2
• The presence of placenta lakes is not listed as a contraindication to aspirin therapy in any major guideline 1
• Aspirin actually improves uteroplacental blood flow and placentation, which may theoretically benefit women with placental vascular issues 3, 4

Determining If Aspirin Is Indicated

Aspirin should be prescribed if the patient has any high-risk factors for preeclampsia:

High-Risk Factors (any one warrants aspirin) 1, 2:

• History of preeclampsia (especially early-onset <34 weeks)
• Chronic hypertension
• Type 1 or type 2 diabetes
• Renal disease
• Autoimmune disease (SLE, antiphospholipid syndrome)
• Multifetal gestation

Multiple Moderate-Risk Factors (consider aspirin with several) 1, 2:

• Nulliparity
• Maternal age ≥35 years
• BMI >30 kg/m²
• Family history of preeclampsia
• Interpregnancy interval ≥10 years

Optimal Dosing and Timing

The most recent high-quality evidence supports higher doses than traditionally recommended:

• Dose: 100-150 mg daily (not the older 81 mg recommendation) 1, 2

  • For women with diabetes specifically: 100-150 mg daily 1
  • For women with chronic hypertension or BMI >40: consider 150 mg daily 2
  • Standard 81 mg dosing has been shown ineffective in certain high-risk populations 2

• Timing: Start between 12-16 weeks of gestation (optimally before 16 weeks) 1, 2

  • Evidence shows doses >100 mg initiated before 16 weeks are significantly more effective (RR 0.33,95% CI 0.19-0.57) 2
  • Starting before 11 weeks is not recommended outside research protocols due to lack of safety data 5

• Duration: Continue daily until delivery (do not stop at 36 weeks) 1, 2

Benefits of Aspirin Therapy

When prescribed appropriately, low-dose aspirin provides:

• 24% reduction in preeclampsia risk 1, 2
• 14% reduction in preterm birth 1
• 20% reduction in intrauterine growth restriction (IUGR) 1, 2
• Improved fetal weight in cases of placental insufficiency 6

Safety Profile

The safety evidence is robust and reassuring:

• No increased risk of placental abruption (even with placental abnormalities) 1, 2
• No increased risk of postpartum hemorrhage 1, 2
• No increased risk of fetal intracranial bleeding 1, 2
• No increased perinatal mortality 1, 2
• No increased risk of congenital anomalies when used at low doses 1, 7

Critical Caveats

Avoid aspirin only if:

• Patient has documented aspirin allergy or intolerance 1
• Active bleeding disorder is present 7
• Patient is taking anticoagulation therapy (requires specialist consultation) 1

Important distinction: The FDA warning about aspirin in pregnancy refers to high doses (>100 mg for analgesic purposes), not the prophylactic low doses (75-150 mg) used for preeclampsia prevention 2

Clinical Implementation

For your patient with placenta lakes:

1. Assess preeclampsia risk factors using the criteria above 1, 2
2. If any high-risk factor is present, prescribe aspirin 100-150 mg daily 1, 2
3. Start between 12-16 weeks if not already initiated 1, 2
4. Continue until delivery 1, 2
5. Monitor placenta lakes per standard obstetric protocols, but do not discontinue aspirin based on their presence alone 1

The presence of placenta lakes should prompt careful obstetric monitoring but does not contraindicate aspirin therapy when otherwise indicated for preeclampsia prevention.