Mature eggs are known as “M2” eggs. Immature eggs come as two types: germinal vesicle (GV) or metaphase 1 (M1). Eggs mature starting from a GV, then to M1, then to M2. A GV is less mature than an M1.
Traditional IVM involves a modified IVF cycle to collect immature eggs only, which are then matured in the lab using specialized culture media.
In a standard IVF cycle, mature and immature eggs can be collected. Rescue IVM is a way to “rescue” these immature eggs and make them mature, so they can be inseminated and develop into embryos. The immature eggs are cultured either for a few hours after retrieval or overnight, which causes them to mature. Often, no specialized equipment or culture media are used to achieve this.
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