Placenta Accreta Spectrum: Correlation between FIGO Clinical Classification and Histopathologic Findings

Area of Science:

• Obstetrics and Gynecology
• Perinatal Medicine
• Surgical Pathology

Background:

• Placenta accreta spectrum (PAS) encompasses a range of placental adherence and invasion issues with varying clinical impact.
• Histopathology is the gold standard for confirming PAS, but it is only available post-treatment.
• The International Federation of Gynecology and Obstetrics (FIGO) introduced a clinical classification system for PAS assignable at delivery.

Purpose of the Study:

• To evaluate the association between the new FIGO clinical classification and histopathologic findings in PAS.
• To assess the correlation between the FIGO classification and maternal outcomes in patients with PAS.

Main Methods:

• Retrospective cohort study of 185 patients with histopathologically confirmed PAS.
• Two experienced surgeons assigned FIGO grades based on delivery findings; a third reviewer adjudicated.
• Statistical analysis included chi-squared tests, Fisher exact test, and multivariate modeling.

Main Results:

• Histopathology revealed 41 (22%) placenta accreta, 44 (24%) placenta increta, and 100 (54%) placenta percreta.
• Substantial inter-rater reliability (Kappa = 0.661) was observed for FIGO grading.
• A significant association was found between histopathology and FIGO clinical classification (p < 0.001), but not with maternal complications.

Conclusions:

• The FIGO clinical classification demonstrates a strong association with histopathologic diagnoses of PAS.
• This classification system improves understanding of placental invasion depth and extent.
• Standardization of reporting and future research in PAS can be facilitated by the FIGO classification.