RELATIONSHIP BETWEEN CIRCULATING HUMAN CHORIONIC-GONADOTROPIN LEVELS AND PREMATURE LUTEINIZATION IN CYCLES OF CONTROLLED OVARIAN HYPERSTIMULATION

Objective: To determine if premature luteinization (serum P levels > 1 .1 ng/mL on or before the day of hCG administration) during controlled ovarian hyperstimulation (COH) is associated with elevated levels of serum hCG. Setting: Tertiary fertility center. Design: Retrospective e valuation of ovum donors undergoing COH. Patients: Forty-four women un derwent COH. Comparisons of serum hCG levels and hormonal and cycle ch aracteristics were made between cycles with premature luteinization (g roup I) and without premature luteinization (group II). Results: Group I (16 women) were similar to women in group II in age, amount of hMG, and the ratio of FSH:hMG received. Both groups received hCG on simila r days, but women in group I had higher peak E(2) levels. Serum hCG le vels increased and correlated with serum P levels in group I only and were higher on the day of hCG administration (group I 1.8 +/- 0.9 mIU/ mL versus group II 1.2 +/- 0.45 mIU/mL; conversion factor to SI unit, 1.00). Peak E(2) and LH levels, ampules of hMG and the FSH:LH ratio, a nd day of hCG administration did not correlate with hCG levels. Human chorionic gonadotropin exposure, as measured by area under the curve, was significantly higher in group I compared with group II. Conclusion : Higher serum levels of hCG and integrated hCG exposure are found in COH cycles with premature luteinization compared with cycles without p remature luteinization. Higher hCG levels may be due to decreased clea rance of hCG from the circulation and/or the hCG content of hMG.