Pathologically Diagnosed Placenta Accreta and Hemorrhagic Morbidity in a Subsequent Pregnancy

To identify the relationship between pathologically diagnosed placenta accreta and risk of major morbidity in a subsequent pregnancy.

We conducted a retrospective cohort study of patients with pathologically diagnosed placenta accreta in an index pregnancy who returned with a subsequent pregnancy at our academic center from 2007 to 2015. Subsequent delivery outcomes included minor, major, or no morbidity. Minor morbidity included estimated blood loss 500-1,500 cc for vaginal and 1,000-1,500 cc for cesarean delivery, transfusion of one to three units of red cells, and minor surgical procedures. Major morbidity included estimated blood loss greater than 1,500 cc, transfusion of greater than three units of red cells, uterine artery embolization, unplanned laparotomy, or hysterectomy.

Three hundred thirty-nine patients with pathologically diagnosed accreta did not undergo hysterectomy, and 39 (11.5%) of these returned for subsequent delivery. Of these, 14 (36%) had accretas that had been identified clinically in the index pregnancy. Twenty-one (54%) experienced morbidity in the index pregnancy, 16 of these (76%) minor and five (24%) major. Of patients without morbidity in the first pregnancy, none experienced major morbidity in a subsequent pregnancy, whereas 6 of 21 (29%) with any index morbidity had a subsequent major morbid outcome (P=.02). Of those with a morbid index delivery, 25% had either a clinical or pathologic accreta diagnosis at follow-up compared with none of those who index accreta was nonmorbid (P=.05).

Risk for major hemorrhagic morbidity after a prior pathologically diagnosed accreta depends on the clinical context. Preparation for major blood loss is indicated after any prior pregnancy complicated by hemorrhage or treatment of retained placenta with a pathologic accreta.