Abstract
Objective Placenta accreta is a feared pathology, in part, because prenatal diagnosis is imperfect.
It is not known whether clinical risk factors or sonographic features equally predict
the entire graded pathological spectrum of placental overinvasion disease nor whether
clinical outcomes differ along the spectrum.
Study Design We conducted a mixed methods retrospective study of a cohort of women screened sonographically
for placenta accreta, cross-referenced against cases identified by pathological diagnosis
(N = 416). Demographic, diagnostic, and outcome information were compared across the
spectrum of invasive placentation: percreta, increta, accreta, and focal accreta not
requiring hysterectomy. The t-test, chi-square, Mann–Whitney, and Kruskal–Wallis tests were used for statistical
analysis across groups.
Results As the depth of invasion decreased, risk factors for placental overinvasion were
less common, especially placenta previa and previous cesarean. There was also reduced
anticipation by sonographic examination of the placenta. Rates of adverse outcomes
were lower among women with focal accreta compared with those with deeper invasion.
Conclusion As the depth of invasion decreases, clinical risk factors and sonographic evaluation
are less reliable in the antenatal prediction of placenta accreta. The potential for
unanticipated morbidity underscores the need for improved diagnostic tools for placenta
accreta spectrum.
Keywords
placenta accreta - overinvasive placentation - placenta - retained placenta - ultrasound
