A case-control study of placental lesions associated with pre-eclampsia

To investigate gross and microscopic placental lesions associated with pre-eclampsia and to determine which lesions are most strongly linked to serious pregnancy complications.

A retrospective case-control study of 173 placentas from women with pre-eclampsia and 173 placentas from healthy normotensive women was conducted.

The mean placental weight in the pre-eclampsia group was lower than that recorded for the control group (280 g vs 360 g; P<0.001). Infarcts (65.9% vs 13.2%; P<0.001) and placental abruption (P<0.001) were most frequent among women with pre-eclampsia. Microscopic findings showed the following lesions to be associated with pre-eclampsia: hypermature villi, defined by absence of intermediate villi (72% vs 16%; P<0.001), excessive syncytial knots (90% vs 9%; P<0.001), decidual vasculopathy (51% vs 8%; P<0.001), villous fibrosis (6% vs 0%; P<0.001), erythroblastosis (11% vs 4%; P<0.01), and avascular terminal villi (9% vs 3%; P<0.05). Increased syncytial knots, infarcts, basal decidual vasculopathy, hypermature villi, and placental erythroblastosis were still associated with pre-eclampsia after logistic regression modeling.

Placental lesions most strongly associated with pre-eclampsia were all causes or expressions of placental hypoxia or ischemia, which appears as the primary mechanism of pre-eclampsia.