Browsing by Author "Ramsay, Dylan"
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- ItemTime-lapse analysis and morphokinetic evaluation of fresh vs. vitrified/warmed oocytes, including donor and explorative sibling oocyte cycles(Stellenbosch : Stellenbosch University., 2020-03) Ramsay, Dylan; Windt De Beer, Marie-Lena; Van Waart, Johannes; Els-Smit, Lydia; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Obstetrics and Gynaecology.ENGLISH ABSTRACT: BACKGROUND: Infertility is defined as a disorder of the reproductive system whereby there is failure to achieve a clinical pregnancy after 12 months or more of regular unprotected sexual intercourse. The primary objective of Assisted Reproductive Technologies (ART) is to implement fertilization in instances where corrective therapy for male or female patients cannot yield fertilization. During the past three decades infertility has become more prevalent. In addition to this, the commercialized world has experienced a trend of women conceiving their firstborn within their later reproductive years. This trend of delaying motherhood has thus led to the common use of oocyte vitrification protocols, which have become increasingly robust over the years. The validation of the oocyte vitrification protocol essentially came from the comparison of fresh versus vitrified/warmed oocytes and how they succeeded in in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) outcomes. It was reported that there were no differences in fertilization rates, implantation rate and pregnancy rates when comparing fresh vs. vitrified/warmed oocytes. Furthermore, there is a trend towards implementing morphokinetic analyses to examine the comparisons between fresh and vitrified/frozen oocytes. With the rapid progression in technology within the ART field of medicine, time lapse systems (TLS) presents an extremely unique and promising tool for improving embryo selection. Improvement of embryo selection will only advocate for the production of clinic-specific embryo kinetic models for prediction of success. The more models of embryo selection we create, the more we may understand whether an optimal morphokinetic profile exists. AIMS: Primary aim: To investigate the comparison with fresh and vitrified/warmed oocytes, using TLS imaging, as well as creating a normative range to reference the classification of future embryo developments. Secondary aim: To investigate the embryo development time lapse (TL) time points of sibling oocytes of patients having both fresh and vitrified oocytes used for treatment in the same insemination cycle. MATERIALS AND METHODS: Retrospective study conducted from 2013 to 2017 at Wijnland Fertility Clinic on de-identified, aggregated TL patient oocyte and embryo development data. Data was filtered according to exclusion and inclusion criteria. Statistical analysis rendered descriptive statistics, quantile (median) regression tests, TOST tests, and matched design linear regression model tests. RESULTS: Results indicated an overall delay in time points and durations between time-points for the vitrified/warmed oocyte population, when compared to their fresh counterparts. Using the quantile (median) regression model, it was found that almost all vitrified/warmed timings were slower than their fresh counterparts (p<0.05), whereby t5 (p=0.068; 95% CI) and t9 (p=0.106; 95% CI) were not. Using the TOST method, it was found that at the 5% level of equivalence, no time points showed equivalence (p<0.05; 90% CI; 5%). It was found at the 10% level that there was significant non-equivalence for time points tPB2, tPNa, t2, t4, t6, t8, tSC, tSB, tB and tHB (p<0.05; 90%CI; 10%). This indicated that for the times stated for non-equivalence there was a delay in timings within the vitrified/warmed oocyte population. Conversely, also at the 10% level, it was found that there was significant equivalence for time points tPNf, t3, t5, t7, t9+ and tEB (p<0.05; 90%CI; 10%), This indicated that for the time points stated there was no statistically significant difference in timings with regards to the fresh and vitrified/warmed oocyte population. Lastly, for the sibling oocyte study, there were no consistent patterns found. This was due to the small population size (n=57). CONCLUSION: In conclusion, this study showed that there was a statistically significant overall delay within the timings for vitrified/warmed oocytes when compared to their fresh counterparts. The most statistically significant findings within this study include the delayed vitrified/warmed oocyte time points for tPNa, t2, t4, t8, tSC, tSB and tHB (p<0.05). The most significant clinical finding of this study was the assumption that vitrified/warmed oocytes undergo mitochondrial stress post warming and requires 2-3 hours of culture in order to reboot the cellular machinery to full operating potential. As a result of this assumption it was suggested that vitrified/warmed oocytes exhibit a 1-hour insemination delay in order to give opportunity for mitochondrial recovery post warming. Another crucial finding was that there was a total delay in the vitrified/warmed oocyte population of 8,53 hours, which could lead to the assumption that even though there was a statistically significant lag exhibited within the vitrified/warmed oocyte population, this is most probably not of clinical significance.