P-119 Oxidative stress in the native semen versus strict sperm morphology as predictors of fertilization in couples undergoing IVF

Abstract

Abstract Study question Is oxidative stress in the native semen a better predictor of fertilization that strict sperm morphology in couples undergoing IVF? Summary answer Compared to strict sperm morphology, oxidative stress in the native semen is a better predictor of fertilization than strict sperm morphology in couples undergoing IVF What is known already Oxidative stress (OS) in native semen was studied before by measuring oxidative-reductive potential (ORP) and was found to be a good predictor of fertilization in-vitro with a cut-off point of 1.34 mV/106 sperm/mL below which the fertilizing capacity of the sperm is diminished. Similarly, strict sperm morphology (SM) was shown to be a good predictor of fertilization with a cut-off point around 4%. However, the superiority of either of these parameters as a better predictor of fertilization needs to be determined and one of the best methods to test this theory is in the IVF model (not the ICSI model). Study design, size, duration This prospective cohort study was conducted between September 2017 and December 2018. Couples with unexplained infertility were treated for one cycle of combined IVF/ICSI if 12 oocytes or more were retrieved. If good embryos resulted from IVF, 2 were transferred. If no fertilization occurred from IVF, 2 embryos resulting from ICSI were transferred. All remaining embryos were frozen. A total of 108 couples were enrolled but only 25 fulfilled the criteria and completed the study. Participants/materials, setting, methods A total of 575 oocytes were retrieved from the 25 patients (mean ± SD = 20.5 ± 5.6 oocyte/cycle) but only 3 to 5 oocytes per patient were inseminated by conventional IVF and the rest with ICSI. OS was determined in native semen by measuring oxidative reduction potential (ORP) using the MiOXYS system and the results correlated with the fertilization rate (FR) in the IVF-fertilized oocytes. Strict morphology of the same sample was also determined. Main results and the role of chance Out of the 108 oocytes inseminated with conventional IVF, 36 reached the 2PN stage (FR = 33.3%). The mean (± SD) ORP in the native semen in couples with = >50% IVF fertilization was 1.02 ± 0.1 mV/106 sperm/mL which is significantly lower than in couples with <50% fertilization (2.05 ± 0.7 mV/106 sperm/mL) (P < 0.02). The sensitivity, specificity, PPV, NPV, +LR and –LR of the ORP assay in predicting = >50% fertilization were 70.0%, 60.0%, 53.8%, 75.0%, 0.80 and 0.20 respectively. On the contrary, the mean (± SD) SM in the native semen in couples with = >50% IVF fertilization was 9.0 ± 4.74 which is slightly (but insignificantly) higher than in couples with <50% fertilization (8.5333 ± 5.25) (P > 0.5). The sensitivity, specificity, PPV, NPV, +LR and –LR of SM in predicting = >50% IVF fertilization were 40.0%, 80.0%, 57.1%, 66.7%, 2.00 and 0.75 respectively. The AUC for ORP was equal to 0.854167 with a cut-off point at 1.5692 mV/106 sperm/ml. On the contrary, the AUC for SM was equal to 0.5367 with a cut-off point at 8, denoting that ORP in the native semen is a better predictor of fertilization in IVF compared to SM. Limitations, reasons for caution The small sample size of this study can be considered a limitation but these early results can be further confirmed by larger prospective studies involving couples with various causes of infertility, although the criteria required for the recruitment of these couples are not easy to fulfill. Wider implications of the findings Measurement of ORP in semen should be added as a parameter to evaluate the fertilizing capacity of the sperm in routine sperm analysis. This can help clinicians treating couples with unexplained or male factor infertility determine whether anti-oxidant therapy, IUI, IVF or ICSI is the best management option. Trial registration number No applicable