Placenta accreta spectrum: Welcome progress and a call for standardization.

Placenta accreta spectrum (PAS) is among the most feared causes of maternal morbidity worldwide, and yet few prospective data are available to inform best practice. PAS is rare enough that rigorous study in a single center is difficult, but common enough that most obstetric hospitals now encounter PAS. Management and outcomes vary strikingly between hospitals and best practice, regrettably, is guided more by expert consensus than by level I evidence.