Purpose: to investigate risk factors associated with accretion in placenta previa (PP) patients. Methods: this was a retrospective case-control study of all the records of patients who delivered between 1986-1998 at Maternidade Escola de Vila Nova Cachoeirinha (São Paulo) with a diagnosis of placenta previa. The groups with and without accretion were compared regarding age, parity, previous history of miscarriage, curettage and cesarean section, type of PP and predominant area of placental attachment. Possible associations between the dependent (accretion) and independent (maternal and placental characteristics) variables were evaluated using the chi² test, univariate and multivariate analyses. Results: reviewing 245 cases of PP, two risk factors were significantly associated with accretion: central placenta previa (odds ratio (OR): 2.93) and two or more previous cesarean sections(OR: 2.54). Based on these data, a predictive model was constructed, according to which a patient with central PP and two more previous cesarean sections has a 44.4% risk for accretion. Conclusions: results of the current study may help obstetricians in the classification of their patients with PP in different risk categories for accretion. This could be useful in preparing for possible delivery complications in those patients considered at a higher risk for accretion.
Placenta; Placenta previa; Placenta accreta; Hysterectomy
