Can serum HCG values be used in the differential diagnosis of pregnancy complicated by hypertension?

OBJECTIVE: The aim of our study is to determine whether the serum human chorionic gonadotropin (hCG) level is helpful in the differential diagnosis and in the clinical management and follow-up of preeclampsia, superimposed preeclampsia, and chronic hypertension during the third trimester. MATERIAL AND METHODS: Eighty hypertensive pregnant patients, who had been hospitalized, and 25 normotensive pregnant patients, who attended the outpatient perinatology clinic in Zeynep Kamil Women and Pediatric Diseases Education and Research Hospital between June 2001 and September 2001 were enrolled in the study. These patients were evaluated in five groups: mild preeclamptic, severe preeclamptic, superimposed preeclamptic, chronic hypertensive, and normotensive groups. The geometric means of hCG levels of these groups were compared with each other and cutoff levels for differential diagnosis were determined. RESULTS: The geometric mean of hCG levels was established as 17,361.31 mIU/mL in the mild preeclamptic group, 49,817.59 mIU/mL in the severe preeclamptic group, 41,101.09 mIU/mL in the superimposed preeclamptic group, 12,558.57 mIU/mL in the chronic hypertensive group, and 9647.98 mIU/mL in the normotensive group. When the geometric mean of the severe preeclamptic group was compared with the results of the normotensive patients, mild preeclamptic patients, chronic hypertensive patients, and superimposed preeclamptic patients, the mean hCG value of severe preeclamptic group was statistically significantly higher than all of the other groups (p < 0.001) except for the latter. The geometric mean of hCG levels of severe preeclamptic patients was compared with the geometric mean of hCG levels of superimposed preeclamptic patients (p > 0.05). The geometric mean of hCG levels in the chronic hypertensive group was lower than that of the superimposed preeclamptic group and the difference was statistically significant (p < 0.001). The geometric mean of hCG levels of the chronic hypertensive group was not significantly different from the results of the mild preeclamptic group and the normotensive group. There was, however, a statistically significant difference between the geometric means of hCG levels of mild preeclamptic patients and normotensive group (p < 0.001). The cutoff value of hCG was determined as 25,000 mIU/mL in differentiation of chronic hypertension from the severe preeclampsia, as 20,000 mIU/mL in differentiation of chronic hypertension from the superimposed preeclampsia, and as 30,000 mIU/mL in differentiation of severe preeclampsia from mild preeclampsia. CONCLUSION: The maternal serum hCG level is a useful laboratory tool when managing and treating hypertensive disorders that complicate pregnancy. The serum hCG level is especially significant in severe preeclampsia and superimposed preeclampsia. Therefore, a high serum hCG level can be a helpful marker in the diagnosis and clinical management by preventing possible complications resulting from severe and superimposed preeclampsia.