Incidence, risk factors and perinatal outcomes of unsuspected placenta accreta spectrum disorders: a retrospective cohort study

To identify incidence and underlying risk factors for unsuspected placenta accreta spectrum (uPAS) and compare their perinatal outcomes. Unsuspected PAS cases were diagnosed at the time of delivery, other cases were the control. Potential risk factors were compared. Analyses were made using appropriate univariate analysis. Multivariable regression model was performed to identify risk factors. A total of 339 pathology-confirmed PAS cases were included in the study out of 415,470 deliveries, with 35.4% (n = 120) of the cases being unsuspected. Our results found that cases with a history of uterine synechiae, history of PAS, posterior or bilateral/fundal placenta (compared with anterior placenta) and history of placenta previa were more likely to experience a delayed diagnosis (aOR 7.93, 6.99, 6.30, 2.64, 3.41, respectively). Whereas cases with gravidity > 3, placenta previa and history of prior CS were more likely to be diagnosed antenatally (aOR 0.40, 0.19, 0.36, respectively). Suspected PAS group had a higher proportion of increta/percreta cases and abdominal and pelvic organ injuries, but the perinatal outcomes were more favourable in the suspected group, with a lower median volume of 24-hour blood loss and blood product transfusion. History of uterine synechiae, history of PAS, placenta location, history of placenta previa are barriers that lead to a delayed detection. Quality improvement initiatives targeting these risk factors should be established to improve early suspicion and management of PAS. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.