In vitro maturation for infertility in polyendocrine metabolic ovarian syndrome: a systematic review of treatment protocols and outcomes.

In vitro maturation (IVM) involves the retrieval of immature oocytes from unstimulated or minimally primed antral follicles, with maturation completed in culture. Women with polyendocrine metabolic ovarian syndrome (PMOS), the condition previously known as polycystic ovary syndrome, are the prototypical candidates for oocyte IVM because it largely avoids ovarian hyperstimulation syndrome (OHSS). Several IVM protocols are in clinical use, differing in priming (human chorionic gonadotropin [hCG], follicle-stimulating hormone [FSH], or none) and culture system (standard vs. biphasic capacitation [CAPA-IVM]). We systematically reviewed published data relating to the use of the above IVM protocols in women with PMOS that were identified by literature searching (MEDLINE, Embase, Web of Science, Cochrane). All IVM protocols essentially eliminated OHSS. Oocyte maturation, number of usable embryos, and the live birth rate varied by priming strategy, culture system, and embryo transfer policy. Maturation rates were approximately 50% with standard IVM and 60%-70% with the hCG-primed or biphasic protocols, and live birth rate after a single retrieval was approximately 20%-48%. The CAPA-IVM protocol was associated with the highest maturation and embryo yield, and a randomized trial reported that a fully hormone-free CAPA-IVM protocol is feasible. Obstetric, neonatal, epigenetic, and child-neurodevelopmental outcomes, now reported up to age 5-7 years, are reassuring. Clinical and methodological heterogeneity precluded statistical pooling of data, and the evidence remains dominated by single-center cohorts, with few randomized trials. This article summarizes protocol-specific outcomes, identifies determinants of success, and defines priorities for standardizing IVM and generating higher-quality evidence for the use of IVM in PMOS.