Are Early and Late Preeclampsia Distinct Subclasses of the Disease-What Does the Placenta Reveal?

Objective To compare histopathological differences in placentas from early and late onset preeclampsia, as well as late onset preeclampsia and normal term deliveries Methods This prospective study was performed at Tygerberg Hospital, a secondary and tertiary referral center in South Africa Placentas from 100 women, 25 each with early and late onset preeclampsia, and an equal number of controls matched for gestational age, underwent routine preparation and were evaluated independently by two pathologists in a strictly predetermined, standardized manner Results Compared to late preeclampsia, placentas in the early preeclampsia group were smaller (p < 0 01), had more infarction (odds ratio [OR] = 4 03, 95% confidence interval [CI] = 1 2-13 5) and inappropriate maturation (OR = 16 62, 95% CI = 4 1-68 0) Placentas from the late onset preeclampsia group showed increased decidual arteriopathy (OR = 5 09, 95% CI = 1 45-17 92) and abruptio placentae (OR = 5 41, 95% CI = 1 01-28 79) compared to controls Conclusions The early and late onset preeclampsia placentas showed clear histopathological differences, whereas late onset preeclampsia and normal term placentas differed less These findings support the contention that early and late onset preeclampsia are different subclasses of disease