Elevated serum nicked and urinary beta-core fragment hCG in preeclamptic pregnancies

Objective: To determine whether different molecular forms of hCG in serum and urine are elevated in preeclamptic pregnancies. Methods: Forty- three pregnant women were studied: 25 preeclamptic women and 18 normotensive women. Immediately after blood and urine samples were collected, the protease inhibitors leupeptin (0.35 mM) and phenanthroline (22 mM) were added. Various molecular forms of hCG in serum (complete hCG, nonnicked hCG, complete free beta hCG) and in urine (complete hCG, beta-core fragment hCG) were measured by matched immunoassays with a common enzyme-labeled tracer antibody. The nicked hCG assay used a coating of beta-subunit monoclonal antibody with the addition of scavenger antibody to remove nonnicked hCG. Mann-Whitney U test and χ² test were used for statistical analyses. Results: Preeclamptic women had significantly higher median (range) levels of serum complete and nicked hCG than did normotensive women (3620 [850-12,000] versus 2420 [310-4850] ng/mL, P = .024; and 102 [45-275] versus 71 [11-143] ng/mL, P = .010, respectively). Both median (range) urinary complete hCG-creatinine and beta- core fragment-creatinine ratios were significantly higher in preeclamptic women than in normotensive women (37.6 [0.5-185] versus 11.3 [1.9-54], P = .013; and 11.8 [2-67] versus 5.3 [0.3-29], P = .009, respectively). Conclusion: Various molecular forms of hCG in serum and urine were significantly higher in preeclamptic than in normotensive pregnancies.