GnRH agonist as novel luteal support: results of a randomized, parallel group, feasibility study using intranasal administration of buserelin.

Background: The study objective was to investigate whether repeated intranasal administration of a GnRH agonist could provide convenient and safe luteal support.

Methods: Twenty-four patients with unexplained infertility were enrolled. All patients were treated with an aromatase inhibitor. When ovulation trigger criteria were met, patients were randomly allocated to either 5000 IU hCG (group A), or 200 microg intranasal buserelin followed by 100 microg every 3 days (group B), 100 microg every 2 days (group C), or 100 microg every day (group D), up to day 14 of the luteal phase. All patients underwent intrauterine insemination.

Results: Follicular development was similar in all groups with 1.1 +/- 0.3 follicles > or = 16 mm, 229.4 +/- 95.2 pg/ml estradiol (E2) and 0.8 +/- 0.5 ng/ml progesterone (mean+/-SD). The luteal phase duration (median; 95% confidence interval) was 15 (14.1, 15.0), 14 (12.5, 15.5), 15 (11.8, 18.2) and 15 (14.4, 15.6) days in groups A, B, C and D respectively. From luteal phase day 7 onwards, progesterone levels tended to be higher in group D compared with A. On day 14 of the luteal phase, progesterone levels were 3.0 (0.8, 5.2), 1.7 (-0.5, 3.9), 3.9 (-0.7, 8.5) and 7.7 (3.4, 11.9) ng/ml in groups A, B, C and D respectively (P = 0.045). No pregnancy was recorded in group A, but there was one biochemical pregnancy in group B, one biochemical and one singleton clinical pregnancy in group C, and two singleton clinical pregnancies in group D.

Conclusion: Intranasal administration of buserelin could be effective to provide luteal support. This treatment was associated with a good pregnancy rate (5/18, 28%).