What is the management plan for a pregnancy at 22 weeks with identified placental lakes?

Management of Placental Lakes at 22 Weeks Gestation

Placental lakes identified at 22 weeks gestation generally do not require specific intervention or change in routine prenatal care, as they are not independently associated with adverse pregnancy outcomes.

What are Placental Lakes?

Placental lakes are sonolucent, anechoic areas within the placenta that represent pools of maternal blood. They appear as:

• Homogenous sonolucent avillous lesions
• Usually greater than 2 cm × 2 cm in diameter
• May persist or resolve during pregnancy

Clinical Significance and Evidence

The most recent and highest quality evidence shows:

• A 2024 retrospective cohort study found no association between placental lakes (regardless of size) and adverse pregnancy outcomes including low birthweight, cesarean delivery, fetal growth restriction, preterm birth, or severe preeclampsia 1.

• While older studies suggested potential concerns with large placental lakes (>4 cm), the most recent evidence does not support changing management based solely on the presence of placental lakes.

Management Approach

1. Continue routine prenatal care

   • Standard anatomy scan at 18-22 weeks
   • Regular growth assessments as per normal protocol

2. Monitor for other risk factors

   • If placental lakes are accompanied by other findings suggestive of placental insufficiency, such as:
     • Abnormal umbilical artery Doppler studies
     • Evidence of fetal growth restriction
     • Abnormal uterine artery Doppler
     • Then management should be guided by these findings, not the placental lakes themselves

3. Surveillance for fetal growth

   • Follow standard protocols for fetal growth assessment
   • No need for increased surveillance based solely on placental lakes

Special Considerations

If placental lakes are accompanied by other concerning findings:

1. If fetal growth restriction is identified:

   • Perform umbilical artery Doppler studies 2
   • Serial growth assessments every 2-4 weeks 2
   • Consider delivery timing based on severity of growth restriction and Doppler findings:
     • Normal Doppler: Consider delivery at 38-39 weeks 2
     • Decreased diastolic flow: Consider delivery at >37 weeks 2
     • Absent end-diastolic flow: Consider delivery at 33-34 weeks 2
     • Reversed end-diastolic flow: Consider delivery at 30-32 weeks 2

2. If placenta previa is also present:

   • Re-evaluate at 28 weeks for persistence of previa 2
   • If placenta previa persists after 28 weeks, avoid moderate-to-vigorous physical activity 2

Conclusion

Based on the most recent evidence, placental lakes identified at 22 weeks gestation:

• Do not independently warrant increased surveillance
• Should not alter standard prenatal care
• Should be considered an incidental finding unless accompanied by other markers of placental dysfunction or fetal compromise

If other risk factors or abnormal findings develop during pregnancy, management should be guided by those specific findings according to established guidelines.