Human Reproduction, Vol. 4, No. 6, pp. 643-646, 1989
© 1989 European Society of Human Reproduction and Embryology
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Delayed occurrence of an LH surge after HCG administration during ovarian stimulation with gonadotrophins: effect of LHRH treatment
Department of Obstetrics and Gynecology, Division of Reproductive Endocrinology and Infertility, University of California, Irvine Medical Center 101 The City Drive, Bldg 41, Orange, CA 92668, USA
Correspondence: 1To whom correspondence should be addressed
Previous studies have shown the appearance of a spontaneous luteinizing hormone (LH) surge after human chorionic gonadotrophin (HCG) administration in human menopausal gonadotrophin (HMG)/HCG-stimulated menstrual cycles. In this report we investigated the effect of leuprolide acetate, a long-acting luteinizing hormone releasing hormone (LHRH) agonist, on the occurrence of these post-HCG rises in serum LH. Two groups of patients were included. Group 1: 10 patients receiving HCG as a part of an HMG/HCG protocol for induction of follicular development in an IVF/GIFT program and Group II: 10 patients treated as Group I, but receiving the LHRH agonist leuprolide acetate to inhibit gonadotrophin secretion prior to and during ovarian stimulation. In Group I, none of the patients showed a surge prior to HCG administration. However, an LH surge following HCG treatment was apparent in four patients (40%). Pregnant patients (2/10) had low mean levels (
2.5 mIU/ml LH) in the follicular phase and showed no LH surge after HCG. In Group II, baseline levels of serum LH were reduced significantly (mean, 1.4±0.1 mIU/ml; P&It; 0.001) compared to Group I. No patient showed an LH surge either before or after HCG administration and the occurrence of pregnancy was higher (6/9 transfers) than in Group I. In spite of the differences in pregnancy rates, the combined therapy versus HMG therapy showed no significant difference in number of oocytes collected of serum oestradiol levels. This suggests that high levels of serum LH, whether prior to or after HCG administration, may have a detrimental effect on the establishment of pregnancy despite adequate follicular growth. It is concluded that treatment with LHRH agonist prior to and during HMG stimulation reduces baseline concentrations of serum LH and abolishes post-HCG surges in serum LH. These effects were associated with a significantly higher pregnancy rate compared to treatment with HMG/HCG alone.
Key words: gonadotrophin-releasing hormone/human gonadotrophins/immunoradiometric assay/IVF/ovarian stimulation