A patient with grade IV placenta praevia and a previous caesarean section is found on MRI to have placenta increta involving the posterior bladder wall. According to the FIGO 2018 classification of abnormally invasive placenta (AIP), which finding most specifically indicates placenta percreta?

• A Loss of the normal retroplacental clear zone on ultrasound
• B Placental villi invading the full thickness of the myometrium but not the serosa
• C Placental villi penetrating through the uterine serosa and invading bladder mucosa ✓
• D Irregularity of the uterine serosa–bladder interface without organ invasion

Explanation

The FIGO 2018 AIP classification: placenta accreta = villi directly attached to myometrium without intervening decidua; placenta increta = villi invade into the myometrium; placenta percreta = villi penetrate through the entire myometrium and uterine serosa and may invade adjacent organs (bladder, bowel). Bladder mucosal invasion is pathognomonic of percreta, not increta. Loss of retroplacental clear zone is a sonographic feature of accreta spectrum generally; serosa irregularity without organ invasion may represent increta or early percreta.

Reference: Williams Obstetrics, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.