Résumé : Objective: To explore luteal phase hormone profiles in patients stimulated with recombinant FSH and GnRH antagonist for IVF under two different modes of luteal support: P and P with E2. Design: Prospective randomized study. Setting: Patients in an academic reproductive medicine unit. Patient(s): One hundred and three patients undergoing ovarian stimulation with a fixed dose of 200 IU recombinant FSH and GnRH antagonist. Intervention(s): Patients were randomized to receive luteal phase supplementation, either P vaginally (n = 49) or P and 4 mg E2 orally (n = 54). Main Outcome Measure(s): Hormonal assessment during the luteal phase on days 1, 4, 7, and 10 after the administration of hCG. Result(s): Hormone levels did not differ during the luteal phase between the two groups with the exception of E2 concentration on day 10 after hCG, which was significantly higher in the E2-supplemented group compared with the P group (median 760 pg/mL, range 2,496 vs. median 589.50 pg/mL, range 2,098). Conclusion(s): Addition of 4 mg E2 for luteal support after stimulation with recombinant FSH and GnRH antagonist does not alter significantly the endocrine profile of the luteal phase until day 7 after hCG. At day 10 after hCG, the E2 levels are significantly higher in the E2-supplemented group. © 2007 American Society for Reproductive Medicine.