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 evaluation of ovum donors undergoing COH.

PATIENTS: Forty-four women underwent COH. Comparisons of serum hCG levels and hormonal and cycle characteristics were made between cycles with premature luteinization (group 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 similar days, but women in group I had higher peak E2 levels. Serum hCG levels 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 E2 and LH levels, ampules of hMG and the FSH:LH ratio, and 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 premature luteinization. Higher hCG levels may be due to decreased clearance of hCG from the circulation and/or the hCG content of hMG.