A 32-year-old G3P2 with previous two caesarean sections presents with painless antepartum haemorrhage at 34 weeks. Ultrasound confirms complete placenta praevia with a retroplacental echolucent zone and multiple intraplacental lacunae. The MOST important immediate next investigation is:

• A MRI pelvis without gadolinium
• B Colour Doppler ultrasound of placental vascularity ✓
• C Cystoscopy to assess bladder involvement
• D CT angiography of pelvic vessels

Explanation

In suspected placenta accreta spectrum following placenta praevia with previous uterine scars, colour Doppler ultrasound is the primary next investigation to assess turbulent intraplacental blood flow, bridging vessels, and loss of the retroplacental clear zone. These features help confirm PAS and grade severity. MRI is used as an adjunct when Doppler findings are inconclusive, particularly to assess posterior invasion or parametrial involvement.

Reference: Williams Obstetrics, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.