The effectiveness and safety of in vitro maturation of oocytes versus in vitro fertilization in women with a high antral follicle count

STUDY QUESTION: What is the effectiveness and safety of IVM compared with IVF for the treatment of women with high antral follicle count (AFC)? SUMMARY ANSWER: In women with high AFC undergoing assisted reproductive technique (ART), IVM is an effective alternative compared with IVF, while it eliminates the risk of ovarian hyperstimulation syndrome (OHSS). WHAT IS KNOWN ALREADY: IVM is postulated to be an alternative to conventional IVF to avoid OHSS. It has particular potential in women with high AFC who are known to be at increased risk of OHSS. To date, IVM and IVF have only been compared in small cohort studies. STUDY DESIGN, SIZE AND DURATION: We performed a retrospective cohort study including 919 women, of whom 608 underwent IVM and 311 IVF. The treatments were conducted at IVFMD, My Duc Hospital, Ho Chi Minh, Vietnam, from July 2015 to December 2017. PARTICIPANTS/MATERIALS, SETTING, METHODS: We studied infertile women aged 18-38 years with an indication for ART and with an AFC ≥24. Women received either IVM or IVF treatment depending on patient's or physician's preference. In IVM cycles, women received 3 days of FSH 100 IU/day followed by hCG 10 000 IU. In IVF cycles, women underwent a gonadotropin-releasing hormone antagonist protocol and were triggered with hCG 6500 IU. Outcome measures were live birth rate (LBR) after first embryo transfer and cumulative LBR after one complete cycle, defined as the chance of having live birth after all fresh and frozen transfers of embryos derived from one IVM/IVF cycle. We also report on clinical pregnancy, miscarriage, multiple pregnancy and OHSS. MAIN RESULTS AND THE ROLE OF CHANCE: Baseline characteristics including age and BMI were comparable between groups. In the IVM group (608 started cycles), there were 511 fresh and 167 frozen transfers. In the IVF group (311 started cycles), there were 209 fresh and 185 frozen transfers. The number of mature oocytes, embryos, good embryos and frozen embryos was significantly lower in the IVM compared with the IVF group. LBRs after the first transfer were 222/608 (36.5%) versus 127/311 (40.8%) (adjusted odds ratio [OR], 0.74; 95% confidence interval [CI], 0.42-1.30). Cumulative LBRs after one completed cycle were 239/608 (39.3%) versus 155/311 (49.8%) (adjusted OR, 0.52; 95% CI, 0.30-0.89). OHSS did not occur in the IVM group versus 11/311 (3.5%) in the IVF group. LIMITATIONS AND REASONS FOR CAUTION: Our study is limited by its non-randomized design. Randomized clinical trials are required to precisely compare the outcomes after IVM versus IVF. WIDER IMPLICATIONS OF THE FINDINGS: In infertile women with a high AFC, IVM is a feasible alternative to standard IVF that markedly reduces OHSS and is potentially more patient friendly and cost effective. STUDY FUNDING/COMPETING INTEREST(S): No external funding was sought to support this work. B.W.M. is supported by a National Health Medical Research Council Practitioner Fellowship (GNT1082548). B.W.M. reports consultancy for ObsEva, Merck and Guerbet. All other authors have no conflicts of interest. TRIAL REGISTRATION NUMBER: NA.