Recurrence of Basal Plate Myofibers, with Further Consideration of Pathogenesis

Objectives: Basal plate myofibers (BPMF) may indicate morbid adherence. We assessed recurrence and clinical progression of BPMF. Methods: In 5 years, 135 BPMF placentas were reported. Controls were the first 50 placentas in 2009, none of which had reported BPMF. Results: 32% of BPMF patients had other placentas, with a recurrence rate of 100%. Actin stains were needed for diagnosis in 117/179 cases (65%). These cases had clinical features suggestive of morbid adherence in 69/117 (59%). 23/47 (49%) of BPMF recurrences progressed in severity, 5 to hysterectomy (11%). Thinning of the basal plate, perforating vessels, gaps in the basal plate, and villi under the basal plate were observed in BPMF placentas. Conclusions: These findings appear to validate screening for BPMF. The 100% recurrence rate suggests evaluation for a heritable factor, i.e., protease inhibitor deficiency, which may explain pre-delivery basal plate damage.