Comparison of clinical efficacy of long- versus short-acting gonadotrophin-releasing hormone agonists for pituitary down regulation in fertilisation cycles.

Background: Gonadotrophin-Releasing Hormone agonist (GnRHa) - long and short acting - is used for pituitary down regulation prior to ovarian stimulation in in vitro fertilisation (IVF) treatment. However, there are controversies in the literature as to their effectiveness, dose of gonadotrophin needed subsequently for ovarian stimulation and the clinical outcome.

Objective: The objective of the study was to compare the efficacy of single-dose long-acting GnRHa - goserelin - and daily dose short-acting GnRHa - buserelin - for pituitary down regulation and their clinical outcome in IVF treatment.

Materials And Methods: : This prospective comparative study was undertaken at the IVF centre in National Hospital Abuja, a public tertiary hospital in Nigeria. A total of 114 IVF patients were consecutively allocated into either long-acting GnRHa - goserelin - 3.6 mg single dose (Group A) or short-acting GnRHa - buserelin - 0.5 mg daily (Group B) both starting on day 21 of the cycle preceding the IVF treatment. The effects on pituitary down regulation and treatment outcomes were compared.

Results: Time taken (days) to achieve down regulation (22.6 ± 4.3 vs. 26.1 ± 8.0; P = 0.084) and the mean number of human menopausal gonadotrophin (HMG) doses used (57.7 ± 13.7 vs. 54.2 ± 16.7; P = 0.222) were similar in the two groups. Although the number of oocytes retrieved (9.9 ± 6.7 vs. 7.2 ± 5.0; P = 0.02) and fertilised (6.2 ± 4.4 vs. 4.6 ± 3.5; P = 0.04) were significantly higher in Group A, there was no statistically significant difference in the number of embryos (4.4 ± 2.6 vs. 4.0 ± 3.0; P = 0.850) and clinical pregnancy rate at 6 weeks (49.2% vs. 43.6%; odds ratio 1.249; confidence interval = 0.579-2.612; P = 0.578) in both the groups. While group B had a significantly higher number of hospital visits (P = 0.0001) as well as a higher number of injections (P = 0.0001), the mean cost of GnRHa and gonadotrophin used was significantly higher in Group A (P = 0.043).

Conclusion: Single-dose long-acting GnRHa is as effective as daily dose short-acting GnRHa for pituitary desensitisation prior to controlled ovarian stimulation in IVF cycles.