Comparison of luteal phase profile in gonadotrophin stimulated cycles with or without a gonadotrophin-releasing hormone antagonist.

BACKGROUND: The aim of our study was to explore luteal phase hormone profiles in gonadotrophin-stimulated cycles with or without gonadotrophin-releasing hormone (GnRH) antagonist therapy during intrauterine insemination (IUI). Forty-one infertile couples were recruited in this randomized clinical study. METHODS: The 19 patients included in group A were treated for 21 cycles with recombinant FSH 150 IU/day starting from day 3 of the cycle and with the GnRH antagonist cetrorelix at the dose of 0.25 mg/day starting from the day in which a follicle with a mean diameter of > or =14 mm was seen at ultrasound scan. Cetrorelix was administered until human chorionic gonadotrophin (HCG) administration. The 22 patients included in group B were administered recombinant FSH alone at the same dosage for 27 cycles. RESULTS: The two treatment groups showed a similar increase in progesterone concentration during the luteal phase. In the mid-luteal phase (day 6 after HCG), oestradiol concentrations in group B were significantly higher compared with group A (P < 0.05) but the oestradiol:progesterone ratio was similar in the two groups. Serum LH was completely suppressed during the follicular phase only in group A, concomitantly with GnRH antagonist administration. A total of six pregnancies, all ongoing, were achieved (14.3% per patient and 12.2% per cycle), equally distributed in group A and in group B. CONCLUSION: GnRH antagonists can be safely administered in gonadotrophin-stimulated IUI cycles without luteal phase supplementation because no deleterious effects of GnRH antagonist administration were noted on luteal progesterone concentration or on the duration of the luteal phase.