(337) Risk factors for placenta accreta spectrum disorder among patients with previa and prior cesarean delivery

A retrospective cohort of pregnancies complicated by placenta previa with a history of at least one prior cesarean delivery was collected at one academic institution from 2007-2019. Cases of PAS were identified and graded in accordance with FIGO clinical and pathologic diagnostic criteria. Maternal demographics, clinical characteristics, and outcomes were abstracted from the medical record. Potential risk factors were compared with univariate analyses. A multivariable conditional logistic regression with backward elimination was used to identify independent predictors, retaining any variable associated at p< 0.20.

Results: Our cohort included 180 patients: 73 with and 107 without PAS. PAS was associated with higher parity (median 2, IQR 1,2 vs 1 IQR 1,2, p< 0.01) history of smoking (18% vs 1%, p< 0.01), more prior cesarean deliveries (median 2, IQR 1,2 vs 1 IQR 1,1, p< 0.01), more prior non-cesarean uterine procedures (median 1, IQR 0,2 vs 0, IQR 0,1, p=0.04), classical hysterotomy at prior cesarean section (13% vs. 4%, p=0.04), or prior retained placenta (12% vs 3%, p=0.02). In the regression analysis, former smoking (OR 1.88, 95% CI 1.72, 129.14), prior cesarean deliveries (OR 3.64, 95% CI 2.16, 6.15), and number of prior non-cesarean uterine surgeries (OR 1.27 per additional procedure, 95% CI 1.03-1.57) were statistically significant while history of retained placenta did not reach statistical significance (OR 4.43, 95% CI 0.98, 20.11).

Conclusion: Among patients with placenta previa and at least one prior cesarean delivery, those with PAS are more likely to be former smokers, have more cesarean deliveries, and more prior non-cesarean uterine procedures. These factors can help guide preconception counseling and triage of referrals for targeted ultrasound evaluation.