Clinical Risk Factors for Placenta Accreta or Placenta Percreta: A Case-Control Study.

OBJECTIVES: Uterine scarring is a risk factor for placenta accreta spectrum (PAS) disorder. We aimed to determine the factors related to PAS in women who had previously undergone a cesarean.

METHODS: We performed a case-control study where women who underwent postpartum hysterectomy for placenta accreta/percreta (cases) were matched to all women with a previous cesarean who delivered in the week before each case (controls). Maternal characteristics along with previous cesarean characteristics were compared between cases and controls. Univariate and multivariate logistic regression analyses were performed to determine risk factors related to PAS.

RESULTS: We compared 64 cases of PAS that required hysterectomy to 192 controls. The factors related to PAS were a history of uterine surgery (OR 27.4; 95% CI 5.1-146.5, P < 0.001) and the number of previous cesareans (2 cesareans: OR 7.2; 95% CI 3.4-15.4, P < 0.001; more than 2 cesareans: OR 7.9; 95% CI 2.9-21.5, P < 0.001). In women with a single previous cesarean without previous uterine surgery, an interdelivery interval of fewer than 18 months (OR 6.3; 95% CI 1.8-22.4, P = 0.004) and smoking (OR 5.8; 95% CI 1.2-27.8, P = 0.03) were related to PAS. The gestational age and the cervical dilatation at previous cesarean were not associated with PAS (all with P > 0.05). The lack of data regarding the closure of the uterus at previous cesareans prevents us from drawing solid conclusions.

CONCLUSIONS: Previous uterine surgery, the number of previous cesareans, smoking, and an interdelivery interval of fewer than 18 months after cesarean are significant risk factors for PAS requiring postpartum hysterectomy.