Renal handling of endogenous human chorionic gonadotrophin in preeclampsia

Objective: To test the hypothesis that the elevated maternal serum concentr ation of human chorionic gonadotrophin (hCG) in preeclampsia is due to alte red renal handling of the hormone. Setting: Department of Obstetrics and Gynecology, Al An Hospital, United Ar ab Emirates, a tertiary center affiliated with the Faculty of Medicine and Health Sciences, UAE University. Methods: The renal clearances and handling of endogenous creatinine and hum an chorionic gonadotrophin were compared in 14 normotensive volunteer and 1 4 preeclamptic mothers who received oral hydration at 34-37 weeks' gestatio n. The hCG content in the placentas was estimated immunohistochemically aft er delivery. Results: Maternal serum concentration of hCG (p = 0.0057), the placental hC G immunopositive cell (p < 0.0001), and syncytial knot counts (p < 0.0001) were significantly higher in preeclamptic mothers. The renal clearances of endogenous creatinine and hCG and fractional hCG clearance were not signifi cantly different in both groups. Significantly increased amounts of hCG wer e filtered (p = 0.007) and excreted (p = 0.007) by preeclamptic mothers. On ly a small but fixed proportion of the filtered load of hCG is excreted in both groups and there was a positive coli-elation (r = 0.5, p = 0.005) betw een filtered and excreted loads of hCG. Conclusion: The results indicate increased placental content of hCG in pree clampsia. The resultant increased maternal serum concentration is probably sustained by the mechanism of renal handling of the hormone.