Abstract
Objective To assess the risk factors, adverse obstetrical outcomes, and recurrence risk associated
with pathologically diagnosed occult placenta accreta.
Study Design This was a retrospective observational study of clinically adherent placentas requiring
manual extraction that underwent pathological examination. Cases were defined as those
with histological evidence of placenta accreta, and controls were defined as those
without accreta. All subsequent pregnancies were evaluated to determine the recurrence
risk of occult accreta in future pregnancies.
Results Of 491 women with clinically adherent placentas, 100 (20.1%) with a pathological
diagnosis of occult accreta were compared with 391 (79.9%) without occult accreta.
In bivariable analysis, risk factors associated with occult accreta included a history
of previous cesarean (19 vs. 10.7%; p = 0.03) and prior uterine surgery (35 vs. 19.7%; p = 0.001). Adverse obstetrical outcomes were more common in women with occult accreta
including postpartum hemorrhage (59 vs. 31.7%; p < 0.001) and peripartum hysterectomy (21 vs. 0.3%; p < 0.001). In 130 subsequent pregnancies, there was an increased risk of retained
placenta (42.9 vs. 19%; p = 0.04) and recurrence of occult accreta (29.6 vs. 6.8%; p = 0.05).
Conclusion Occult accreta is associated with an increased risk of hemorrhagic morbidity and
recurrence of morbidly adherent placenta in subsequent pregnancies.
Keywords
retained placenta - focal accreta - postpartum hemorrhage - placental pathology -
occult accretas - histological accreta
