Laboratory Evaluation in the Workup of Preeclampsia

Abstract

INTRODUCTION: Preeclampsia occurs in 6–8% of pregnancies and is the second leading cause of maternal mortality in the United States. Preeclampsia is associated with HELLP (Hemolysis, Elevated Liver enzymes and Low Platelet count) syndrome and it has become a common practice to evaluate for the syndrome with laboratory testing in all women who present with hypertension. Our objective is to investigate the rate of abnormal laboratory values in our population and identify the associated risk factors. METHODS: This is a retrospective analysis of women who presented to Stony Brook University Hospital between January and December 2010 for evaluation of hypertension in pregnancy. The charts were reviewed for demographics, signs and symptoms, blood pressure ranges, and laboratory results. Student's t test, χ2, Pearson, and Spearman correlation tests were used for analysis. RESULTS: Six hundred thirty-three encounters were reviewed and 20 abnormal laboratory tests were identified (3.2%). The abnormalities were elevated liver function tests (14), low platelets (eight), and elevated lactate dehydrogenase (one). Women with abnormal results were more likely to have right upper quadrant pain and twin gestation (P<.001 and P=.03). There was also a small positive correlation between right upper quadrant pain, twin gestation, and elevated 24-hour urine protein with abnormal values. CONCLUSIONS: Only a small percentage of women who were evaluated had abnormal laboratory findings. Three risk factors were identified: right upper quadrant pain, twin gestation, and elevated 24-hour urine protein. These findings call into question their routine use in the evaluation of hypertension in pregnancy. A selective approach based on risk factors may be a more cost-effective approach to the evaluation of these women.