Early and late onset preeclampsia associated with different placental pathology and clinical risk characteristics

Background: Preeclampsia is classified as early onset and late onset types with different clinical manifestation and pathogenesis. Placental pathology of preeclampsia has been largely based on description of the early onset type, and the morphologic features of placenta from late onset preeclampsia were similar to those of non-preeclamptic placentas. Objective: To identify clinically relevant maternal and neonatal risk characteristics and placental pathology for early onset and late onset preeclampsia. Study design We have collected all placental pathology information as well as maternal and neonatal birth information from March 2020 to December 2021 including preeclampsia and non-preeclampsia patients. We compared preterm and term preeclampsia in regards to maternal and neonatal complication and placental pathology by using logistic regression models to determine the important clinical risk factors associated with preeclampsia and placental pathology. Results A total 3724 placentas including 614 placentas from preeclamptic and 3110 non-preeclamptic patients were studied. Preterm preeclampsia (<37 weeks) was similar to early onset preeclampsia (<34 weeks) in maternal and neonatal complications as well as placental pathology, and these features were statistically different from those from term preeclampsia. More male fetuses were associated with early onset preeclampsia and female fetuses associated with late onset term preeclampsia when compared to non-preeclamptic patients. Maternal race/ethnicity and marital status were associated with preeclampsia but this association was no longer significant after logistic regression analysis. Preterm preeclampsia was statistically associated with gestational diabetes, placental infarcts, intrauterine fetal growth restriction and fetal vascular malperfusion, whereas term preeclampsia was associated with decidual vasculopathy and maternal obesity. Conclusions Early onset preeclampsia is a different clinical syndrome from the late onset type with clinical implication of pathogenesis and management.