(1100) Incidence of New Recommended Criteria for Severe Maternal Morbidity in Placenta Accreta Spectrum Disorder

Given that CDC severe maternal morbidity (SMM) definitions classify anticipated interventions in management of PAS as complications, specific standardized criteria for SMM in PAS (PAS-SMM) have been proposed. Our goal was to understand the incidence of PAS-SMM compared to standard SMM criteria in a contemporary cohort.

Study Design:
We conducted a retrospective cohort study of patients with histopathology confirmed PAS managed at large academic center from January 2020-June 2025. Severe maternal morbidity outcomes were obtained from electronic medical records. Categorical variables were compared using Chi square or Fischer's exact and continuous variables were compared with Mann Whitney U. Maternal demographics and delivery outcomes that met criteria for SMM without transfusion and hysterectomy were compared to those with PAS-SMM (see Table 2 for criteria).  Additionally, cases with PAS-SMM were compared to those without.

Results:
During the study time period, 114 cases of PAS were delivered by cesarean hysterectomy. 80% had severe PAS (percreta, n=92) and median gestational age at delivery was 34 [32, 34] weeks. 100% of patients were found to have SMM events by standard definition, however, when transfusion and hysterectomy were excluded, this dropped to 29% (n=34) (p< 0.001). Using PAS-SMM, only 20% (n=23) of patients met SMM criteria. Compared to women without SMM-PAS, PAS-SMM patients had significantly more antenatal vaginal bleeding (p=0.04), blood loss (1500 [950, 2867] vs 3835 [2342, 5500] mL, p=0.001) and unscheduled cases (p=0.001). No cases of immediate maternal death, acute renal failure, cardiogenic shock, acute coronary syndrome, cardiac arrest, or stroke were noted. The most common PAS-SMM outcome was transfusion > 8units pRBCs (n=10, 8%).

Conclusion:
Traditional SMM metrics overstate morbidity in PAS due to inclusion of expected interventions like blood transfusion and hysterectomy. Application of proposed PAS-specific SMM criteria results in a substantially lower and potentially more accurate morbidity rate.