OBJECTIVE: To evaluate the results of the coagulation and liver function studies which are routinely ordered in the hypertensive pregnant patient. It was also the intent of the study to determine the likelihood of a given test being abnormal in a given clinical situation and the possible impact, if any, on obstetrical decision-making.STUDY DESIGN: The records of 244 patients delivered at the Univ. of New Mexico Hospital between 3/91 and 3/94 were examined. Records were selected on the basis of a discharge diagnosis of hypertension, preeclampsia or eclampsia. Statistical analysis was performed with ANOVA and Fisher's Post Hoc Multiple Comparison of Means using SAS. The confidence interval around zero was calculated using a binomial distribution on StatXact. Patients were classified as having either chronic hypertension, PIH, mild preeclampsia, severe preeclampsia, eclampsia, or HELLP syndrome. Patients with chronic hypertension who developed superimposed preeclampsia were classified as preeclamptic.RESULTS: Admission laboratory results were expressed as mean±S.D. as follows: As expected, the mean platelet count was significantly lower (p<.05) in patients with the HELLP syndrome than the other categories, although not statistically significantly lower than that in eclamptic patients. (It should be noted that patients diagnosed with HELLP syndrome ultimately had platelet counts < 100K although mean platelet count was 135K on admission). Patients with severe preeclampsia and eclampsia had significantly lower (p<.05) platelet counts than patients with PIH or chronic hypertension. Mean values of AST, ALT, and LDH were significantly higher (p<.05) in patients with HELLP. Patients with severe preeclampsia and eclampsia had significantly higher (p<.05) LDH values than patients with chronic hypertension, PIH or mild preeclampsia. No patient studied had an abnormal PT or PTT (95% Cl=0-.012).CONCLUSION: Liver function studies and platelet counts tended to correlate with the severity of the patient's disease. LFT's and platelet counts were normal in patients with chronic hypertension. PT and PTT were normal in all patients evaluated and hence, the results of these tests are unlikely to be useful in obstetrical decision-making.