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Poster session I Clinical obstetrics, epidemiology, fetus, medical-surgical complications, neonatalogy, physiology/endocrinology, prematurity: Abstracts 87 - 236| Volume 208, ISSUE 1, SUPPLEMENT , S59, January 01, 2013

107: Placental findings suggesting preeclampsia is at least two different diseases

      Objective

      It has long been suspected that hypertension specific to pregnancy represents at least two different diseases depending on the timing during gestation when preeclampsia is first diagnosed. Early-onset preeclampsia has often been observed to be associated with placental insufficiency attributable to vascular abnormalities; in contrast, late-onset preeclampsia has been associated with excessive placentation manifest as hyperplasia. Our purpose was to evaluate the placental pathology in women with preeclampsia occurring at varying gestational ages.

      Study Design

      This was a secondary analysis of a prospective observational study of placentas from pre-specified complicated pregnancies routinely submitted for standardized examination. For this study, a database of placental diagnoses of liveborn singleton gestations without major malformations was linked to a computerized obstetric database. The rates of standardized placental findings including vascular (atherosis; infarction) and non-vascular (hyperplasia) changes were evaluated according to gestational age and diagnosis of severe preeclampsia.

      Results

      A total of 7,122 women with pregnancies complicated by preeclampsia were delivered at our institution between January 1, 2001 and September 30, 2007. Of these, 1,210 had placental examinations. Within this cohort, 209, 355, and 646 were diagnosed with preeclampsia at < 34, 34 - 36 6/7, and ≥ 37 weeks gestation, respectively. Selected placental findings in women with preeclampsia are shown in the Table.
      Tabled 1
      Table thumbnail grr14

      Conclusion

      The placentas of women with preeclampsia developing before 34 weeks gestation were significantly different from those with preeclampsia at term. The former group demonstrated placental findings predominantly consistent with insufficiency due to vascular abnormalities whereas placental hyperplasia was significantly associated with preeclampsia at term. Such differing placental findings support the hypothesis that preeclamsia is a different disease depending on the gestational age at diagnosis.