Circumvallate placenta, third trimester

This code identifies a specific placental abnormality where the fetal membranes fold back on themselves around the edges of the placenta, forming a thick, raised ring. This condition, known as circumvallate placenta, is being observed during the third trimester of pregnancy. It can be associated with adverse pregnancy outcomes.

Assign this code when documentation explicitly states the presence of a circumvallate placenta identified in the third trimester. This diagnosis is typically made via ultrasound or gross examination of the placenta after delivery. Supporting documentation should confirm the placental morphology and the gestational age at diagnosis.

• Ensure the documentation specifies "circumvallate" and not "circummarginate" placenta, as these are distinct conditions.
• Verify the gestational age (third trimester) to ensure accurate code selection, as other codes exist for different trimesters.
• Code any associated maternal or fetal complications separately, such as preterm labor or fetal growth restriction.