Exploring the Potential of In vitro Maturation (IVM) of Oocytes: Indications, Applications, and Treatment Protocols

Abstract

This review addresses the current understanding of In Vitro Maturation (IVM) treatment, including indications and effective treatment protocols influencing oocyte developmental competence. A comprehensive literature search was performed to gather relevant studies, clinical trials, and reviews related to IVM. Databases such as PubMed, MEDLINE, and pertinent medical journals were searched. The selected literature was analyzed and synthesized to offer a comprehensive overview. IVM has emerged as a promising technique for inducing maturation in immature oocytes across various developmental stages. Its applications extend to areas utilizing In Vitro Fertilization (IVF), gaining traction as a treatment option for Polycystic Ovary Syndrome (PCOS) and fertility preservation in cancer patients. Recent advancements have led to improved global pregnancy rates, resulting in successful births. IVM also holds potential in reducing risks associated with conventional IVF, including ovarian hyperstimulation syndrome and multiple pregnancies. Despite these advantages, IVM adoption in clinical practice remains limited. Ongoing research aims to refine therapeutic protocols and expand clinical indications. IVM holds promise in assisted reproductive technology, spanning applications from cancer patient fertility preservation to addressing PCOS. Enhanced pregnancy rates highlight efficacy, while risk reduction compared to IVF underscores its importance. Further research is needed for optimal use across patient groups, emphasizing protocol refinement and expanded applications.

Keywords: Clinical protocol; Fertility preservation; In vitro maturation oocyte (IVM).

Figure 1.

Major IVM protocols. A) The main protocol of IVM, in which GV-stage COCs that are immature are developed to MII in vitro in a single step. A-a) Patients not get an hCG bolus prior Oocyte Pick-Up (OPU). A-b) Patients get a bolus of hCG prior to OPU, +/− prior FSH priming. Only around 10–20% of the oocytes you collect will be in the MII stage; some of them are in the MI stage and majority are in the GV stage. The various phases of meiosis that occur during OPU required distinct types of treatment in the laboratory: MII need to be fertilized on the same day as OPU, while maturing and immature oocytes need IVM culture. B) A biphasic IVM protocol is similar to the standard IVM, except that it includes an extra pre-IVM culture stage. In this protocol, COCs are placed in a meiosis-promoting medium after intentionally arresting immature cumulus-enclosed oocytes for 24 hr. Patients may receive prior FSH priming, but hCG priming is inappropriate due to the need for intact compact COCs in this platform. C) This protocol involves maturing immature oocytes in the GV stage in vitro, which are obtained from conventional IVF cycles after ovarian stimulation and ovulation triggering, often using hCG. In most IVF centers, these oocytes are considered medically useless and are discarded. Rescue IVM oocytes are always cultivated without cumulus cells from GV to MII because these cells are removed after OPU before ICSI.