ii) Find out the correct correlation :
FHS : Development of oocyte :: LH:
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Answer:
During controlled ovarian stimulation (OS), follicles of different size develop, which are monitored by transvaginal sonography (TVS). The decision of the follicle size at which final oocyte maturation should be triggered is a critical step in OS. It is well known that oocyte maturity is linked with follicle size1. One of the most widely applied protocols is administering the trigger when several follicles have reached a diameter of ≥ 18 mm1-6. However, this strategy was based on the previous finding that small follicles are associated with low oocyte recovery rates2, 7, 8. Furthermore, reduced maturity and fertilization capacity for oocytes retrieved from small follicles were reported, followed by the recommendation not to aspirate this pool of follicles2, 7-10. However, other studies did not find differences in oocyte recovery rate11 or fertilization rate (FR), between small and large follicles5, 12. Most importantly, some publications demonstrated decreased FR and developmental competence in oocytes derived from very large (> 23 mm) follicles, indicating adverse effects of prolonged stimulation9, 13. Similarly, controversial results on the relationship between follicular size and embryo cleavage rates were reported5, 6, 10, 11. These discordant findings might be attributed to differences in OS protocols, patient characteristics, workflows, techniques to measure follicular volume and size, methods of oocyte insemination (in‐vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI)) and analysis of endpoints (fertilization and cleavage rates, and embryo quality). To date, few studies have analyzed the relationship between blastocyst development or clinical outcome and follicular size following one‐by‐one follicle measurement10, 11, 14.
To shed more light on the controversial findings regarding the optimal follicular size for oocyte retrieval evalulated by conventional two‐dimensional TVS, we aimed to perform a prospective study using three‐dimensional (3D) TVS, which is considered a more accurate method for evaluation of spherical and non‐spherical follicle volumes. We investigated the correlation between follicle size and oocyte competence as well as embryo development to blastocyst stage. In addition, clinical outcome was evaluated in terms of implantation, pregnancy, clinical pregnancy and live‐birth (LBR) rates. In order to substantiate our findings, follicular fluid (FF) samples from different follicle cohorts were collected to identify putative biomarkers for oocyte quality and competence in relation to follicle growth.
Explanation: