Browsing by Author "Steyn, Cheyenne"

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    Effect of human male patient diagnosis on syngamy timing and blastulation using time-lapse technology
    (Stellenbosch : Stellenbosch University, 2019-04) Steyn, Cheyenne; Windt De Beer, Marie-Lena; Els-Smit, Lydia; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Obstetrics and Gynaecology.
    BACKGROUND: Improving embryo selection for embryo transfer is essential in Assisted Reproductive Technologies (ART), especially in single embryo transfer settings to reduce multiple birth rate. Current selection methods are largely based on assessment of morphological characteristics. Morphological blastocyst parameters have been shown in literature to correlate with implantation and live birth success rates, while female age is well established to affect overall assisted reproductive technology outcomes. More recently, kinetic parameters from time lapse (TL) technology have also emerged as additional selection characteristics during embryo development. As of yet, the effect of certain patient factors on kinetic parameters is to be elucidated. Syngamy is the merging event of maternal and paternal deoxyribonucleic acid (DNA) during fertilization and can be accurately determined / visualized using TL. The functional centrosome within the spermatozoa contributes to chromosome alignment and combination, therefore possibly impacting syngamy. The paternal genome from the spermatozoon also possibly contributes to blastulation on day 5 of embryo development by playing a role in the embryo genome activation, which drives advanced embryo development. The kinetic time points generated by TL technology during embryo development, can be used to examine the potential effect of male fertility diagnosis on syngamy and blastulation. This may elucidate whether syngamy timing is a relevant kinetic parameter that can allow more accurate selection and prediction of good quality embryos. AIMS: Primary aim: To investigate the possible measurable direct effect of male fertility prognosis using TL, on the time duration to the syngamy fertilization event. Secondary aim: To investigate the subsequent effect of male fertility prognosis using TL, on syngamy timing and the resulting advanced embryo development and blastocyst quality. MATERIALS AND METHODS: This was a retrospective study that was conducted from 2017 to 2018 at Wijnland Fertility clinic on de-identified, aggregated TL patient embryo data from 2013 to 2016. Data was filtered according to inclusion and exclusion criteria and categorized according to defined male prognosis groups (good prognosis (GP), poor prognosis (PP), and very poor prognosis (VP)). Data was submitted for statistical analysis (statistical significance: P < 0.05). Female age was compensated for during statistical analysis. RESULTS: Results indicated that all three male prognosis groups (GP, PP, VP) had similar rates of normal fertilization (60.12%, 58.84%, and 54.29%, P = 0.19) and subsequent blastulation (64.75%, 69.61%, and 63.28%, P = 0.25). The GP group showed significantly shorter syngamy timing compared to the VP group (19.73 ± 3.69 hours vs 20.80 ± 4.71 hours, P = 0.02). Shorter syngamy timing significantly correlated with increased blastocyst expansion on day 5 of embryo development in all groups (P < 0.01). A shorter syngamy timing significantly correlated with A-grade trophectoderm epithelium (TE) quality compared to B-grade (P = 0.02). A-grade TE in the GP group (P = 0.05) and VP group showed significantly shorter syngamy timing compared to B-grade in the VP group (P =0.04). Syngamy timing did not show any significant correlation with inner cell mass (ICM) quality (P = 0.36) or between male prognosis groups (P = 0.13). CONCLUSION: Results indicated that although fertilization and blastulation rate amongst the male prognosis groups were similar, poorer male prognosis may lead to extended syngamy timing and poorer blastocysts, impacting expansion and trophectoderm epithelium quality specifically. Since these two blastocyst parameters are the most important indicators of embryo implantation potential, syngamy can therefore be an early predictive marker for blastocyst quality, irrespective of initial sperm prognosis.