A 38-year-old grand multipara (G5P4) with a previous cesarean section delivers a placenta that fails to separate after 30 minutes of active management. Ultrasound reveals myometrial thinning with lacunae. She is taken to the operating room and found to have a placenta increta. According to the FIGO classification of abnormally invasive placenta, which placenta accreta spectrum (PAS) grade correlates with invasion into but not through the myometrium?

• A PAS Grade 1 (placenta accreta)
• B PAS Grade 2 (placenta increta) ✓
• C PAS Grade 3a (percreta without bladder involvement)
• D PAS Grade 3c (percreta with bladder and ureter involvement)

Explanation

The FIGO 2019 / International Society for Abnormally Invasive Placenta (IS-AIP) classification grades PAS histologically: Grade 1 (accreta) = villi attach to myometrium without invasion; Grade 2 (increta) = villi invade INTO but not through the full thickness of the myometrium; Grade 3a–3c (percreta) = villi penetrate through the full myometrium to the serosa (3a), to bladder or bowel (3b), or to ureter/pelvic side wall (3c). This patient's finding of invasion into but not through the myometrium is Grade 2.

Reference: Williams Obstetrics, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.