Oocyte selection

{{Short description|Procedure performed prior to IVF}} {{cs1 config|name-list-style=vanc|display-authors=6}} '''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.

Not all women can conceive naturally, leaving them with a need for technologies and research that can help them have children. Women who might not be able to have their kids naturally may have the option of in vitro fertilization. In vitro fertilization can be a series of treatments that involves the fertilization of a mature egg with a sperm in a laboratory.<ref>{{Cite web |title=In vitro fertilization (IVF) - Mayo Clinic |url=https://www.mayoclinic.org/tests-procedures/in-vitro-fertilization/about/pac-20384716 |access-date=2024-03-26 |website=www.mayoclinic.org |language=en}}</ref> Oocyte selection is a part the process for in vitro fertilization.<ref>{{Cite web |date=2024-03-14 |title=Definition of OOCYTE |url=https://www.merriam-webster.com/dictionary/oocyte |access-date=2024-03-25 |website=www.merriam-webster.com |language=en}}</ref> An Oocyte is an egg/ovum that is not fully mature or developed and has not been fertilized; Therefore an oocyte is an undeveloped ovum.

__TOC__

== Process == thumb|This illustrates the process for accessing oocyte quality before in vitro fertilization Selecting an oocyte for in vitro fertilization involves assessing the quality of the oocyte which is usually done by accessing the morphological features of the oocyte. The major parts of the oocyte that are accessed for quality in terms of morphological characteristics are the cumulus cells, zona pellucida, polar body, perivitelline space, and cytoplasm; These are the main parts of the oocyte and are usually assessed by conventional microscopy.<ref>{{cite journal | vauthors = Lemseffer Y, Terret ME, Campillo C, Labrune E | title = Methods for Assessing Oocyte Quality: A Review of Literature | journal = Biomedicines | volume = 10 | issue = 9 | pages = 2184 | date = September 2022 | pmid = 36140285 | pmc = 9495944 | doi = 10.3390/biomedicines10092184 | doi-access = free }}</ref> The size of an oocyte is another factor of the quality of the oocyte; Larger oocyte are usually more quality than smaller ones. <ref>{{cite journal | vauthors = Wiegel RE, Rubini E, Rousian M, Schoenmakers S, Laven JS, Willemsen SP, Baart EB, Steegers-Theunissen RP | title = Human oocyte area is associated with preimplantation embryo usage and early embryo development: the Rotterdam Periconception Cohort | journal = Journal of Assisted Reproduction and Genetics | volume = 40 | issue = 6 | pages = 1495–1506 | date = June 2023 | pmid = 37129725 | pmc = 10310608 | doi = 10.1007/s10815-023-02803-1 }}</ref> 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).<ref>{{cite journal | vauthors = Strassburger D, Goldstein A, Friedler S, Raziel A, Kasterstein E, Mashevich M, Schachter M, Ron-El R, Reish O | title = The cytogenetic constitution of embryos derived from immature (metaphase I) oocytes obtained after ovarian hyperstimulation | journal = Fertility and Sterility | volume = 94 | issue = 3 | pages = 971–978 | date = August 2010 | pmid = 19505687 | doi = 10.1016/j.fertnstert.2009.04.035 | doi-access = free }}</ref>

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.<ref>{{cite journal | vauthors = Rienzi L, Vajta G, Ubaldi F | title = Predictive value of oocyte morphology in human IVF: a systematic review of the literature | journal = Human Reproduction Update | volume = 17 | issue = 1 | pages = 34–45 | year = 2010 | pmid = 20639518 | pmc = 3001337 | doi = 10.1093/humupd/dmq029 }}</ref> Suggested techniques include ''zona pellucida imaging'', which can detect differences in birefringence between eggs, which is a predictor of compaction, blastulation and pregnancy.<ref>{{cite journal | vauthors = Ebner T, Balaban B, Moser M, Shebl O, Urman B, Ata B, Tews G | title = Automatic user-independent zona pellucida imaging at the oocyte stage allows for the prediction of preimplantation development | journal = Fertility and Sterility | volume = 94 | issue = 3 | pages = 913–920 | date = August 2010 | pmid = 19439291 | doi = 10.1016/j.fertnstert.2009.03.106 | doi-access = free }}</ref>

Potentially, polar body biopsy may be used for molecular analysis, and can be used for preimplantation genetic screening.<ref name="JiaoWoodruff2013">{{cite journal | vauthors = Jiao ZX, Woodruff TK | title = Detection and quantification of maternal-effect gene transcripts in mouse second polar bodies: potential markers of embryo developmental competence | journal = Fertility and Sterility | volume = 99 | issue = 7 | pages = 2055–2061 | date = June 2013 | pmid = 23465709 | pmc = 3672332 | doi = 10.1016/j.fertnstert.2013.02.003 | author2-link = Teresa Woodruff }}</ref>

== References == {{reflist}}

{{DEFAULTSORT:Oocyte selection}} Category:Fertility Category:In vitro fertilisation Category:Female genital procedures Category:Cryobiology Category:Fertility medicine Category:Obstetrics Category:Human pregnancy Category:Reproduction