In-vitro maturation of oocytes versus conventional IVF in women with infertility and a high antral follicle count: a randomized non-inferiority controlled trial

STUDY QUESTION: Is one cycle of IVM non-inferior to one cycle of conventional in IVF with respect to live birth rates in women with high antral follicle counts (AFCs)? SUMMARY ANSWER: We could not demonstrate non-inferiority of IVM compared with IVF. WHAT IS KNOWN ALREADY: IVF with ovarian hyperstimulation has limitations in some subgroups of women at high risk of ovarian stimulation, such as those with polycystic ovary syndrome. IVM is an alternative ART for these women. IVM may be a feasible alternative to IVF in women with a high AFC, but there is a lack of data from randomized clinical trials comparing IVM with IVF in women at high risk of ovarian hyperstimulation syndrome. STUDY DESIGN, SIZE, DURATION: This single-center, randomized, controlled non-inferiority trial was conducted at an academic infertility center in Vietnam from January 2018 to April 2019. PARTICIPANTS/MATERIALS, SETTING, METHODS: In total, 546 women with an indication for ART and a high AFC (>24 follicles in both ovaries) were randomized to the IVM (n = 273) group or the IVF (n = 273) group; each underwent one cycle of IVM with a prematuration step versus one cycle of IVF using a standard gonadotropin-releasing hormone antagonist protocol with gonadotropin-releasing hormone agonist triggering. The primary endpoint was live birth rate after the first embryo transfer. The non-inferiority margin for IVM versus IVF was 10%. MAIN RESULTS AND THE ROLE OF CHANCE: Live birth after the first embryo transfer occurred in 96 women (35.2%) in the IVM group and 118 women (43.2%) in the IVF group (absolute risk difference -8.1%; 95% confidence interval (CI) -16.6%, 0.5%). Cumulative ongoing pregnancy rates at 12 months after randomization were 44.0% in the IVM group and 62.6% in the IVF group (absolute risk difference -18.7%; 95% CI -27.3%, -10.1%). Ovarian hyperstimulation syndrome did not occur in the IVM group, versus two cases in the IVF group. There were no statistically significant differences between the IVM and IVF groups with respect to the occurrence of pregnancy complications, obstetric and perinatal complications, preterm delivery, birth weight and neonatal complications. LIMITATIONS, REASONS FOR CAUTION: The main limitation of the study was its open-label design. In addition, the findings are only applicable to IVM conducted using the prematuration step protocol used in this study. Finally, the single ethnicity population limits the external generalizability of the findings. WIDER IMPLICATIONS OF THE FINDINGS: Our randomized clinical trial compares live birth rates after IVM and IVF. Although IVM is a viable and safe alternative to IVF that may be suitable for some women seeking a mild ART approach, the current study findings approach inferiority for IVM compared with IVF when cumulative outcomes are considered. Future research should incorporate multiple cycles of IVM in the study design to estimate cumulative fertility outcomes and better inform clinical decision-making.