Endometrium receptivity in in-vitro maturation (IVM) treatment

Abstract

OBJECTIVE: Transforming endometrium from a mid-follicular to an effective luteal environment in IVM-cycles is challenging. Failure to obtain a receptive endometrium may underlie unsuccessful implantation in IVM. Research focussing on endometrium histology in IVM cycles is scarce. DESIGN: A prospective cohort pilot study in 41 normo-ovulatory volunteers and 9 with PCOS. MATERIALS AND METHODS: Oocytes were matured and fertilized for research purposes. No embryos were transferred, but endometrial development was investigated. Endometrial priming consisted of 450 IU uFSH, followed by 6 mg daily transdermal estradiol gel (10 mg if endometrium thickness was < 8 mm) and 600 mg daily vaginal progesterone. 20 volunteers received a final oocyte maturation trigger using 5000 IU hCG; 30 received no such trigger. Endometrium receptivity was assessed using vaginal ultrasound scanning and histological analysis of endometrium biopsies performed during the luteal phase of an IVM-cycle (on either day 4, 5, 6 or 7 after oocyte retrieval). RESULTS: Endometrium histology did not correlate with endometrium thickness and was not significantly influenced by hCG-triggering. According to Noyes' criteria, 40,0 % (14/34) resp. 37,5 % (3/8) of representative samples from non-PCOS reps. PCOS volunteers showed a receptive endometrium. Overall, 56,3 % had an endometrium maturation delay exceeding 2 days, of which 33,3 % showed no secretory changes at all. CONCLUSION: A receptive endometrium is a prerequisite for successful implantation. In IVM-cycles, the results of our pilot study show a high incidence of secretory defects in spite of standard hormonal endometrial priming. Further research is needed to establish an optimal hormonal treatment protocol in IVM-cycles and to identify molecular markers that indicate a competent endometrium.