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U.S., Canada Need Narrower Severe Preeclampsia Definition


 

LISBON — The definition of severe preeclampsia that's been adopted by the U.S. National High Blood Pressure Education Program contains some criteria that did not lead to adverse maternal outcomes in an analysis of 657 patients.

Based on these findings, a narrower definition of severe preeclampsia is warranted, with a narrower list of criteria used to justify delivery for maternal indications, Dr. Peter von Dadelszen and his associates reported in a poster at the 15th World Congress of the International Society for the Study of Hypertension in Pregnancy.

Three criteria that did not shake out as adverse-outcome predictors from the list of the National High Blood Pressure Education Program (NHBPEP) were proteinuria, persistent headache or other cerebral or visual disturbances, and persistent epigastric pain, reported the poster's authors, including Dr. Dadelszen, an ob.gyn. at the University of British Columbia, Vancouver. The NHBPEP Working Group on High Blood Pressure in Pregnancy published its revised recommendations in 2000.

The researchers found that the severe preeclampsia criteria of the Canadian Hypertension Society also included several diagnostic markers that weren't associated with adverse outcomes in the current study, including proteinuria, low serum albumin, severe nausea, intrauterine growth restriction, oligohydramnios, headache, and right upper quadrant pain.

The study was done at six hospitals in Canada, the United Kingdom, and New Zealand during September 2003 to May 2006. It included 657 women who were diagnosed with preeclampsia, superimposed preeclampsia, or HELLP syndrome (hemolysis, elevated liver enzymes, and low platelets). For this study, preeclampsia was defined as a blood pressure of at least 140/90 mm Hg and proteinuria or hyperuricemia.

The researchers identified the clinical markers that were statistically significant predictors of adverse maternal outcomes in this group. The adverse outcomes included death, hepatic dysfunction, acute renal failure, eclampsia, pulmonary edema, and need for any transfusion.

The multivariate analysis identified these factors as independent predictors of adverse outcomes: blood pressure at or above 160/110 mm Hg, platelets less than 100 × 10

All of these conditions are diagnostic criteria in both the NHBPEP and Canadian Hypertension Society guidelines, except chest pain or dyspnea and placental abruption, which don't appear in the NHBPEP definition of severe preeclampsia, the researchers said. However, the researchers did not suggest that the NHBPEP needed to expand its criteria to match the Canadian guidelines.

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