Oocyte selection is a procedure that is performed prior to in vitro fertilization, in order to use oocytes with maximal chances of resulting in pregnancy. In contrast, embryo selection takes place after fertilization.
Chromosomal evaluation may be performed. Embryos from rescued in vitro-matured metaphase II (IVM-MII) oocytes show significantly higher fertilization rates and more blastomeres per embryo compared with those from arrested metaphase I (MI) oocytes (58.5% vs. 43.9% and 5.7 vs. 5.0, respectively).
Also, morphological features of the oocyte that can be obtained by standard light or polarized light microscopy. However, there is no clear tendency in recent publications to a general increase in predictive value of morphological features. Suggested techniques include zona pellucida imaging, which can detect differences in birefringence between eggs, which is a predictor of compaction, blastulation and pregnancy.
- Strassburger D, Goldstein A, Friedler S, et al. (June 2009). "The cytogenetic constitution of embryos derived from immature (metaphase I) oocytes obtained after ovarian hyperstimulation". Fertil. Steril. 94 (3): 971–978. doi:10.1016/j.fertnstert.2009.04.035. PMID 19505687.
- Rienzi, L.; Vajta, G.; Ubaldi, F. (2010). "Predictive value of oocyte morphology in human IVF: a systematic review of the literature". Human Reproduction Update 17 (1): 34–45. doi:10.1093/humupd/dmq029. PMC 3001337. PMID 20639518.
- Ebner T, Balaban B, Moser M, et al. (May 2009). "Automatic user-independent zona pellucida imaging at the oocyte stage allows for the prediction of preimplantation development". Fertil. Steril. 94 (3): 913–920. doi:10.1016/j.fertnstert.2009.03.106. PMID 19439291.