A woman with a previous cesarean section has a low-lying anterior placenta at 20 weeks ultrasound. At delivery (36 weeks), placenta is found to be morbidly adherent. Which sonographic feature in the third trimester BEST predicts placenta percreta specifically (invasion into adjacent organs)?

• A Retroplacental clear space loss on grey scale ultrasound
• B Multiple placental lacunae with turbulent flow on Doppler
• C Bladder wall interruption and parametrial vascularity on Doppler ✓
• D Thinning of the myometrium overlying the placenta (<1 mm)

Explanation

Bladder wall interruption (loss of the normal hyperechoic bladder-uterine serosa interface) combined with parametrial or vesicovaginal vascularity on color Doppler indicates percreta — full-thickness myometrial invasion into adjacent organs (most commonly the bladder). Loss of retroplacental clear space and multiple lacunae indicate accreta/increta. Myometrial thinning suggests increta but not necessarily percreta-level invasion.

Reference: Williams Obstetrics, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.