A 34-year-old woman with two previous cesarean sections undergoes ultrasound at 20 weeks. The placenta is anterior and covers the internal os; there is loss of the retroplacental clear zone and multiple lacunae with turbulent flow on color Doppler. The MOST likely diagnosis is:

• A Placenta accreta spectrum — increta ✓
• B Placenta previa totalis
• C Placenta accreta spectrum — percreta
• D Vasa previa type II

Explanation

Loss of the retroplacental clear zone combined with placental lacunae and prior uterine scar suggest placenta accreta spectrum (PAS). Placenta increta specifically shows myometrial invasion (loss of clear zone, myometrial thinning) but without bladder invasion. Bladder wall irregularity and breakthrough into bladder indicate percreta. Multiple placental lacunae ('Swiss cheese' pattern) with loss of clear zone is the hallmark sonographic finding of increta when bladder is uninvolved. Two prior cesarean sections with anterior previa place this patient at high PAS risk.

Reference: Williams Obstetrics, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.