The Place of In Vitro Maturation in Assisted Reproductive Technology

In vitro maturation (IVM) is an assisted reproductive technology (ART) whereby immature cumulus-oocyte complexes are collected and matured in vitro, without need for controlled ovarian stimulation and ovulation triggering. Advantages of IVM over in vitro fertilization (IVF) include mild or no stimulation, lower medication costs and less patient burden. However, early clinical outcomes with IVM were suboptimal. More recently, clinical studies reported live birth rates after IVM of about 40%. New IVM culture systems are being used to improve the efficacy of IVM. These have been in widespread use for animals for many years and are now showing promise in the clinical setting. Patients more likely to benefit from IVM over IVF include those at risk of OHSS (e.g. women with polycystic ovary syndrome), when the time for ovarian stimulation is limited, or where sustained elevations of estradiol are contraindicated (e.g. oncofertility indications). The main barrier to use of IVM to date was its relative efficacy compared with IVF, and there have also been concerns over the health of infants born following IVM. However, no differences in congenital abnormalities between IVM and other ARTs have been identified. In addition, there is a lack of both experience and standardized protocols. Strategies to overcome barriers to the use of IVM include better training for clinicians, more and better funded research in the field, and improved recognition of IVM by fertility specialists. Overall, IVM offers a valuable alternative for ART in select patient populations. New approaches to IVM appear to have the potential to achieve pregnancy outcomes equivalent to those after IVF. Increasing the use of IVM in the future can be achieved with improved training and education for fertility specialists, and increased funding for IVM research, with the ultimate goal of improving fertility outcomes.