Maternal RNA Factors stored by the oocyte that are used to drive early embryo division for the first 3 days. Synonyms: stored oocyte factors Related Articles: Embryo Arrest Glossary: Oocyte activation Artificial oocyte activation improves IVF outcomes in clinical trial Early evidence suggests rapamycin may benefit aging eggs and improve IVF outcomes Monthly IVF research roundup (March 2026)