Abnormal endometrial development occurs during the luteal phase of nonsupplemented donor cycles treated with recombinant follicle-stimulating hormone and gonadotropin- releasing hormone antagonists  Efstratios M Kolibianakis, MD, Claire Bourgain, MD, Peter Platteau, MD, Carola Albano, MD, Andre C Van Steirteghem, MD, PhD, Paul Devroey, MD, PhD  Fertility and Sterility  Volume 80, Issue 2, Pages 464-466 (August 2003) DOI: 10.1016/S0015-0282(03)00663-0

FIGURE 1 Difference between histologic and chronologic dating of endometrium at oocyte pick-up (open circles) and the mid-luteal phase (closed circles) after stimulation with recombinant FSH and GnRH antagonists and no luteal phase supplementation. Kolibianakis. GnRH antagonists and luteal phase endometrium.Fertil Steril 2003. Fertility and Sterility 2003 80, 464-466DOI: (10.1016/S0015-0282(03)00663-0)