The effect of sperm DNA fragmentation on live birth rate after IVF or ICSI: a systematic review and meta-analysis

Quantifying the association of sperm DNA fragmentation with assisted reproductive technology outcomes: An umbrella review

BACKGROUND

Systematic reviews and meta-analyses are instrumental in shaping clinical practice. However, their findings can sometimes be marred by discrepancies and potential biases, thereby diluting the strength of the evidence presented. Umbrella reviews serve to comprehensively assess and synthesise these reviews, offering a clearer insight into the quality of the evidence presented. In the context of the relationship between sperm DNA fragmentation (SDF) and assisted conception outcomes, there is a divergence in the literature. Some reviews suggest a clear cause-and-effect linkage, whereas others present conflicting or inconclusive results.

OBJECTIVES

In this umbrella review we aimed to synthesise the evidence collated in systematic reviews and meta-analyses summarising the association of SDF with assisted reproductive technology (ART) outcomes.

SEARCH STRATEGY

After preregistration (https://doi.org/10.17605/OSF.IO/6JHDP), we performed a comprehensive search of the PubMed, Scopus, Cochrane Library, Web of Science and Embase databases. We conducted a search for systematic reviews on the association between SDF and ART without any restrictions on language or publication date.

SELECTION CRITERIA

Systematic reviews and meta-analyses assessing the association between SDF and ART outcomes were eligible.

DATA COLLECTION AND ANALYSIS

We assessed the quality of the included reviews using AMSTAR 2 and ROBIS, and determined the degree of overlap of primary studies between reviews estimating the corrected covered area (CCA), adjusted for structural missingness. We evaluated the most recent reviews assessing the association of SDF with live birth, pregnancy, miscarriage, implantation, blastulation and fertilisation. The synthesis of evidence was harmonised across all included quantitative syntheses, re-estimating the odds ratio (eOR) in random-effects meta-analyses with 95% confidence intervals (95% CIs) and 95% prediction intervals (95% PIs). We categorised the evidence strength into convincing, highly suggestive, suggestive, weak or nonsignificant, according to the meta-analysis re-estimated P-value, total sample size, I2 statistic for heterogeneity, small study effect, excess significance bias and the largest study significance.

MAIN RESULTS

We initially captured and screened 49 332 records. After excluding duplicate and ineligible articles, 22 systematic reviews, 15 of which were meta-analyses, were selected. The 22 reviews showed a moderate degree of overlap (adjusted CCA 9.2%) in their included studies (overall n = 428, with 180 unique studies). The 15 meta-analyses exhibited a high degree of overlap (adjusted CCA = 13.6%) in their included studies (overall n = 274, with 118 unique studies). AMSTAR 2 categorised the quality of evidence in 18 reviews as critically low and the quality of evidence in four reviews as low. ROBIS categorised all the reviews as having a high risk of bias. The re-estimated results showed that the association of SDF with live birth was weak in one and nonsignificant in four meta-analyses. Similarly, the association of SDF with pregnancy, miscarriage, implantation, blastulation and fertilisation was also weak or nonsignificant. The association of high SDF with different ART outcomes was also weak or nonsignificant for different interventions (IVF, ICSI and IUI) and tests.

CONCLUSIONS

This umbrella review did not find convincing or suggestive evidence linking SDF with ART outcomes. Caution should be exercised in making any claims, policies or recommendations concerning SDF.

A 2-step remote TUNEL approach for sperm DNA fragmentation assessment. Analysis in donors and patients

OBJECTIVES

Infertility is a disease of the male or female reproductive systems. Male reproductive workup is based on routine semen analysis, although of limited value. The 2021 WHO Manual incorporated Sperm DNA Fragmentation (SDF) assessment, and highlighted the need for individual laboratories to define suitable thresholds. This study aimed to present an alternative to address this issue, determine an SDF cut-off value with fertile donors, and characterize SDF in a patient cohort and their relationship with semen parameters.

STUDY DESIGN

A service unit was established to remotely perform TUNEL assay in a 2 step-process. Semen samples were received at andrology laboratories, subjected to routine semen analysis (WHO, 2010), partially processed and transported to the service unit for SDF evaluation. Using this setting, studies were done in fertile donors (n = 15) to define the cut-off value, and in men undergoing infertility workup (n = 318).

RESULTS

A cut-off value of 9.17 % was determined with the fertile donor cohort. With this cut-off, a 64.46 % abnormal SDF incidence was determined in the patient cohort. SDF negatively correlated with sperm number, vitality and motility, and positively with abnormal morphology and male age (P < 0.05). TUNEL-positive cases depicted lower sperm quality and higher male age (P < 0.05). A similar abnormal SDF incidence was determined among patients with semen abnormalities. Asthenozoospermic and ≥40 years patient samples depicted higher (P < 0.05) SDF than those of the general population. SDF incidence was also high in normozoospermic patients.

CONCLUSIONS

Using a 2-step remote approach with a standardized procedure and an SDF cut-off value established with fertile donors, high SDF incidence in semen samples depicting normal and abnormal quality were identified in men consulting for infertility, highlighting the relevance of its evaluation as part of the male fertility workup.

Insight on cytotoxic NHC gold(I) halide complexes evaluated in multifaceted culture systems

Gold complexes can be a useful system in the fight against cancer. Although many studies have been carried out on in vitro 2D cell culture models embryotoxic assays are particularly lacking. Embryotoxicity and DNA damage are critical concerns in drug development. In this study, the effects of a new N-Heterocyclic carbene (NHC)-Au compound (Bromo[1,3-di-4-methoxybenzyl-4,5-bis(4-methoxyphenyl)imidazol-2-ylidene]gold(I)) at different concentrations were explored using multifaceted approach, encompassing 2D cancer cell cultures, in vivo zebrafish and in vitro bovine models, and compared with a consolidated similar complex (Bromo[1,3-diethyl-4,5-bis(4-methoxyphenyl)imidazol-2-ylidene]gold(I)). The results obtained from 2D cancer cell cultures revealed concentration-dependent effects of the gold compounds by estimating the cytotoxicity with MTT assay and cellular damage as indicated by LDH release. Selected concentrations of gold complexes demonstrated no adverse effects on zebrafish embryo development. However, in bovine embryos, these same concentrations led to significant impairments in the early developmental stages, triggering cell apoptosis and reducing blastocyst competence. These findings underscore the importance of evaluating drug effects across different model systems to comprehensively assess their safety and potential impact on embryonic development.

Sperm Chromatin Dispersion Test Detects Sperm DNA Fragmentation Mainly Associated with Unviable Spermatozoa and Underestimates the Values with Respect to TUNEL Assay

Several clinical laboratories assess sperm DNA fragmentation (sDF) in addition to semen analysis in male infertility diagnosis. Among tests evaluating sDF, TUNEL (Terminal deoxynucleotidyl transferase dUTP nick end labeling) and SCD (Sperm Chromatin Dispersion) are widely used. Our lab developed a modified version of TUNEL (TUNEL/PI) able to distinguish two sperm populations (PI Brighter and PI Dimmer) differently associated with sperm viability and reproductive outcomes. The aim of this study was to compare sDF levels detected by SCD and TUNEL/PI in the semen samples from 71 male subjects attending our Andrology Laboratory. Our results demonstrate that SCD is less sensitive in determining sDF compared to TUNEL/PI. The statistically significant positive correlation found between sDF evaluated by SCD and PI Dimmer (consisting of all dead spermatozoa) suggests that SCD mainly detects sDF in unviable spermatozoa. We confirmed that most spermatozoa detected by SCD are unviable by performing SCD after incubation in hypo-osmotic medium to discriminate viable and unviable cells in 52 samples. Such results might explain the lower ability of this test in discriminating couples having successful ART outcomes demonstrated in published metanalyses. Overall, our results indicate that SCD is less sensitive in evaluating sDF for diagnostic purposes.

Human Papillomavirus and Male Infertility: What Do We Know?

In recent years, increasing attention has been paid to understanding the causes of infertility, which is being recognized as a growing health problem affecting large numbers of couples worldwide. Male infertility is a contributing factor in approximately 30-40% of cases, and one of its etiological causes is sexually transmitted infections (STIs). Among sexually transmitted pathogens, human papillomavirus (HPV) can contribute in various ways to the failure of spontaneous and assisted reproduction, acting in the different phases of conception, especially in the early ones. In particular, HPV infection can affect sperm DNA integrity, sperm motility, count, viability, and morphology and can induce the production of anti-sperm antibodies (ASAs). In this narrative review, we aimed to provide an overview of existing research on the potential adverse effects of HPV infection on male reproductive health. Furthermore, we analyzed how limiting the spread of the infection, particularly with gender-neutral vaccination, could be a possible therapeutic tool to counteract male and female fertility problems.

Good practice recommendations on add-ons in reproductive medicine†

STUDY QUESTION

Which add-ons are safe and effective to be used in ART treatment?

SUMMARY ANSWER

Forty-two recommendations were formulated on the use of add-ons in the diagnosis of fertility problems, the IVF laboratory and clinical management of IVF treatment.

WHAT IS KNOWN ALREADY

The innovative nature of ART combined with the extremely high motivation of the patients has opened the door to the wide application of what has become known as 'add-ons' in reproductive medicine. These supplementary options are available to patients in addition to standard fertility procedures, typically incurring an additional cost. A diverse array of supplementary options is made available, encompassing tests, drugs, equipment, complementary or alternative therapies, laboratory procedures, and surgical interventions. These options share the common aim of stating to enhance pregnancy or live birth rates, mitigate the risk of miscarriage, or expedite the time to achieving pregnancy.

STUDY DESIGN, SIZE, DURATION

ESHRE aimed to develop clinically relevant and evidence-based recommendations focusing on the safety and efficacy of add-ons currently used in fertility procedures in order to improve the quality of care for patients with infertility.

PARTICIPANTS/MATERIALS, SETTING, METHODS

ESHRE appointed a European multidisciplinary working group consisting of practising clinicians, embryologists, and researchers who have demonstrated leadership and expertise in the care and research of infertility. Patient representatives were included in the working group. To ensure that the guidelines are evidence-based, the literature identified from a systematic search was reviewed and critically appraised. In the absence of any clear scientific evidence, recommendations were based on the professional experience and consensus of the working group. The guidelines are thus based on the best available evidence and expert agreement. Prior to publication, the guidelines were reviewed by 46 independent international reviewers. A total of 272 comments were received and incorporated where relevant.

MAIN RESULTS AND THE ROLE OF CHANCE

The multidisciplinary working group formulated 42 recommendations in three sections; diagnosis and diagnostic tests, laboratory tests and interventions, and clinical management.

LIMITATIONS, REASONS FOR CAUTION

Of the 42 recommendations, none could be based on high-quality evidence and only four could be based on moderate-quality evidence, implicating that 95% of the recommendations are supported only by low-quality randomized controlled trials, observational data, professional experience, or consensus of the development group.

WIDER IMPLICATIONS OF THE FINDINGS

These guidelines offer valuable direction for healthcare professionals who are responsible for the care of patients undergoing ART treatment for infertility. Their purpose is to promote safe and effective ART treatment, enabling patients to make informed decisions based on realistic expectations. The guidelines aim to ensure that patients are fully informed about the various treatment options available to them and the likelihood of any additional treatment or test to improve the chance of achieving a live birth.

STUDY FUNDING/COMPETING INTEREST(S)

All costs relating to the development process were covered from ESHRE funds. There was no external funding of the development process or manuscript production. K.L. reports speakers fees from Merck and was part of a research study by Vitrolife (unpaid). T.E. reports consulting fees from Gynemed, speakers fees from Gynemed and is part of the scientific advisory board of Hamilton Thorne. N.P.P. reports grants from Merck Serono, Ferring Pharmaceutical, Theramex, Gedeon Richter, Organon, Roche, IBSA and Besins Healthcare, speakers fees from Merck Serono, Ferring Pharmaceutical, Theramex, Gedeon Richter, Organon, Roche, IBSA and Besins Healthcare. S.R.H. declares being managing director of Fertility Europe, a not-for-profit organization receiving financial support from ESHRE. I.S. is a scientific advisor for and has stock options from Alife Health, is co-founder of IVFvision LTD (unpaid) and received speakers' fee from the 2023 ART Young Leader Prestige workshop in China. A.P. reports grants from Gedeon Richter, Ferring Pharmaceuticals and Merck A/S, consulting fees from Preglem, Novo Nordisk, Ferring Pharmaceuticals, Gedeon Richter, Cryos and Merck A/S, speakers fees from Gedeon Richter, Ferring Pharmaceuticals, Merck A/S, Theramex and Organon, travel fees from Gedeon Richter. The other authors disclosed no conflicts of interest.

DISCLAIMER

This Good Practice Recommendations (GPRs) document represents the views of ESHRE, which are the result of consensus between the relevant ESHRE stakeholders and are based on the scientific evidence available at the time of preparation.ESHRE GPRs should be used for information and educational purposes. They should not be interpreted as setting a standard of care or bedeemedinclusive of all proper methods of care, or be exclusive of other methods of care reasonably directed to obtaining the same results.Theydo not replace the need for application of clinical judgement to each individual presentation, or variations based on locality and facility type.Furthermore, ESHRE GPRs do not constitute or imply the endorsement, or favouring, of any of the included technologies by ESHRE.

[Testicular and epididymal sperm extraction surgery]

BACKGROUND

Testicular and epididymal sperm extraction surgery is a frequent procedure. However, to date, there has been no French consensus on the technique to be preferred in the various situations of male infertility and on the best way to perform them. We therefore decided to proceed with a formalized expert consensus, using the method recommended by the French National Authority for Health. The aim was to provide the French urology community with practical advice on how best to perform these procedures.

METHODS

Twenty-six international experts met online for the consensus. A research committee carried out a comprehensive literature review and prepared the 55 statements submitted to the rating group. After 2 rounds of scoring, 50 recommendations were validated in March 2023, having achieved a consensus of more than 85% among the experts.

RESULTS

The consensus covered (1) preparation for sperm extraction surgery, (2) the different sperm extraction surgery techniques (Microsurgical epididymal sperm aspiration [MESA], Percutaneous epididymal sperm aspiration [PESA], Conventional Testicular Sperm Extraction [TESE], Microsurgical Testicular Sperm Extraction [micro-TESE]), (3) advice to be given to the patient concerning the postoperative period, before presenting the results of the sperm extraction surgeries.

CONCLUSIONS

The expert consensus meeting on the performance of sperm extraction surgery presented a set of clinical guidelines based on the available literature and expert opinion. These guidelines should have a favourable effect on the development of this activity in France.

Surgically retrieved spermatozoa for ICSI cycles in non-azoospermic males with high sperm DNA fragmentation in semen

Intracytoplasmic sperm injection (ICSI) using surgically retrieved spermatozoa outside the classic context of azoospermia has been increasingly used to overcome infertility. The primary indications include high levels of sperm DNA damage in ejaculated spermatozoa and severe oligozoospermia or cryptozoospermia, particularly in couples with ICSI failure for no apparent reason. Current evidence suggests that surgically retrieved spermatozoa for ICSI in the above context improves  outcomes, mainly concerning pregnancy and miscarriage rates. The reasons are not fully understood but may be related to the lower levels of DNA damage in spermatozoa retrieved from the testis compared with ejaculated counterparts. These findings are consistent with the notion that excessive sperm DNA damage  can be a limiting factor responsible for the failure to conceive. Using testicular in preference of low-quality ejaculated spermatozoa bypasses post-testicular sperm DNA damage caused primarily by oxidative stress, thus increasing the likelihood of oocyte fertilization by genomically intact spermatozoa. Despite the overall favorable results, data remain limited, and mainly concern males with confirmed sperm DNA damage in the ejaculate. Additionally, information regarding the health of ICSI offspring resulting from the use of surgically retrieved spermatoa of non-azoospermic males is still lacking. Efforts should be made to improve the male partner's reproductive health for safer ICSI utilization. A comprehensive andrological evaluation aiming to identify and treat the underlying male infertility factor contributing to sperm DNA damage is essential for achieving this goal.

Only the Best of the Bunch-Sperm Preparation Is Not Just about Numbers

In this Seminar, we present an overview of the current and emerging methods and technologies for optimizing the man and the sperm sample for fertility treatment. We argue that sperms are the secret to success, and that there are many avenues for improving both treatment and basic understanding of their role in outcomes. These outcomes encompass not just whether treatment is successful or not, but the wider intergenerational health of the offspring. We discuss outstanding challenges and opportunities of new technologies such as microfluidics and artificial intelligence, including potential pitfalls and advantages. This article aims to provide a comprehensive overview of the importance of sperm in fertility treatment and suggests future directions for research and innovation.

Unraveling the Impact of Sperm DNA Fragmentation on Reproductive Outcomes

In recent years, there has been a growing interest in identifying subcellular causes of male infertility, and sperm DNA fragmentation (SDF) research has been at the forefront of this focus. DNA damage can occur during spermatogenesis due to faulty chromatin compaction or excessive abortive apoptosis. It can also happen as sperm transit through the genital tract, often induced by oxidative stress. There are several methods for SDF testing, with the sperm chromatin structure assay, terminal deoxynucleotidyl transferase d-UTI nick end labeling (TUNEL) assay, comet assay, and sperm chromatin dispersion test being the most commonly used. Numerous studies strongly support the negative impact of SDF on male fertility potential. DNA damage has been linked to various morphological and functional sperm abnormalities, ultimately affecting natural conception and assisted reproductive technology outcomes. This evidence-based review aims to explore how SDF influences male reproduction and provide insights into available therapeutic options to minimize its detrimental impact.

[Assessment of the man in the infertile couple]

BACKGROUND

Among couples consulting for infertility, there is a male component, either alone or associated with a female aetiology in around one in 2 cases.

MATERIAL AND METHODS

Bibliographic search in PubMed using the keywords "male infertility", "diagnosis", "management" and "evaluation" limited to clinical articles in English and French prior to 1/01/2023.

RESULTS

The AFU recommends: (1) a complete medical history including: family history, patient history affecting fertility, lifestyle habits (toxicity), treatments, symptoms, sexual dysfunctions; (2) a physical examination including: BMI, signs of hypogonadism, secondary sexual characteristics, scrotal examination (volume and consistency of testes, vas deferens, epididymal or testicular nodules, presence of varicocele); (3) two spermograms, if abnormal on the first; (4) a systematic scrotal ultrasound,± an endorectal ultrasound depending on the clinic; (5) a hormonal work-up (testosterone, FSH; if testosterone is low: LH assay to differentiate between central or peripheral hypogonadism); (6) karyotype if sperm concentration≤10 million/mL; (7) evaluation of Y chromosome microdeletions if concentration≤1 million/mL; (8) evaluation of the CFTR gene in cases of suspected bilateral or unilateral agenesis of the vas deferens and seminal vesicles. The role and usefulness of direct and indirect tests to assess the effects of oxidative stress on sperm DNA will also be explained.

CONCLUSION

This review complements and updates the AFU/SALF 2021 recommendations.

[Varicocele and male infertility]

BACKGROUND

Varicocele is the most common correctable cause of male infertility. It was the subject of recent Association française d'urologie (AFU) Comité d'andrologie et de médecine sexuelle (CAMS) recommendations. Since then, the literature has provided additional information. This review will comprehensively reassess current indications for the treatment of varicocele, and revisit contemporary issues in the light of current advances.

METHODS

Update of the literature search carried out as part of the CAMS recommendations for the period between 2020 and 2023.

RESULTS

Microsurgical sub-inguinal varicocelectomy remains the surgical treatment of choice for infertile men with clinical varicocele and abnormal sperm parameters. It offers recurrence rates of less than 4%. It significantly improves both natural and in vitro fertilization live birth and pregnancy rates, as well as sperm count, total and progressive motility, morphology and DNA fragmentation rates. All in all, it modifies the MPA strategy in around one in two cases. Varicocele grade and bilaterality are predictive of improved sperm parameters and pregnancy rate. Treatment of subclinical varicocele is not recommended. Complications are rare, notably hydroceles (0.5%), unilateral testicular atrophy due to arterial damage (1/1000), hematomas, delayed healing and postoperative pain. Retrograde embolization is an alternative to surgery.

CONCLUSION

Whenever possible, the urologist should present and discuss treatment options for varicocele with the MPA team and the patient, taking a personalized approach.

From Diagnosis to Treatment: Comprehensive Care by Reproductive Urologists in Assisted Reproductive Technology

Infertility is a global health concern, with male factors playing an especially large role. Unfortunately, however, the contributions made by reproductive urologists in managing male infertility under assisted reproductive technology (ART) often go undervalued. This narrative review highlights the important role played by reproductive urologists in diagnosing and treating male infertility as well as any barriers they face when providing services. This manuscript presents a comprehensive review of reproductive urologists' role in managing male infertility, outlining their expertise in diagnosing and managing male infertility as well as reversible causes and performing surgical techniques such as sperm retrieval. This manuscript investigates the barriers limiting urologist involvement such as limited availability, awareness among healthcare professionals, and financial constraints. This study highlights a decrease in male fertility due to lifestyle factors like sedentary behavior, obesity, and substance abuse. It stresses the significance of conducting an evaluation process involving both male and female partners to identify any underlying factors contributing to infertility and to identify patients who do not require any interventions beyond ART. We conclude that engaging urologists more effectively in infertility management is key to optimizing fertility outcomes among couples undergoing assisted reproductive technology treatments and requires greater education among healthcare providers regarding the role urologists and lifestyle factors that could have an effect on male fertility.

Sperm DNA fragmentation and its interaction with female factors

High levels of sperm deoxyribonucleic acid (DNA) fragmentation have been associated with adverse reproductive outcomes, including low natural and assisted pregnancy rates, abnormal embryonic development, and recurrent pregnancy loss. These poor outcomes are likely caused by unrepaired DNA damage exceeding a critical repair threshold, adversely affecting normal embryo development. In these cases, DNA repair mechanisms of the oocyte may play a significant role in compensating for sperm DNA damage, preserving normal embryo development, and enhancing reproductive outcomes.

Explaining the Unexplained: Examining the Predictive Value of Semen Parameters, Sperm DNA Fragmentation and Metal Levels in Unexplained Infertility

Background

There is ongoing research to find an optimum modality to predict male fertility potential.

Aims

To compare the semen parameters, sperm DNA damage and seminal metal levels of Zinc, Lead and Aluminium among the male partners of couples with unexplained infertility and men with proven fertility.

Settings and Design

Prospective case-control study at a tertiary level teaching hospital.

Materials and Methods

One hundred male partners of couples with unexplained subfertility and 50 men with proven fertility were included in the study. Male partners of unexplained infertility couples and fertile men were compared for their semen parameters, sperm DNA Fragmentation Index (DFI) and seminal metal levels in semen.

Statistical Analysis Used

Chi-square test, Student's t-test, sensitivity and specificity analysis, binomial logistic regression analysis.

Results

Fertile men had statistically significantly higher mean progressive sperm motility than male partners of unexplained infertility (53.12 ± 9.89% vs. 44.81 ± 19.47%, P = 0.005). Semen volume and sperm concentration were comparable among the cases and control population. The mean sperm DFI was significantly lower among fertile men (10.83 ± 6.28 vs. 21.38 ± 10.28, P < 0.0001). Plotting the receiver-operating characteristic curve the threshold for discrimination was calculated to be 18% DFI. The sensitivity specificity and overall accuracy were 43%, 84% and 56.67%, respectively when the DFI cut-off was set at 18%. Zinc concentration in the semen had a strong positive correlation (Point Biserial correlation coefficient = 0.831) with fertility, whereas lead and aluminium had a moderate negative correlation.

Conclusion

Conventional semen analysis had limited differentiating ability for unexplained infertility. The sperm DFI may be employed for explanatory purposes among couples with unexplained subfertility. A lower discriminatory threshold of DFI (18%) has better overall accuracy as opposed to a 30% cutpoint for unexplained subfertility. Among metals, Zinc was strongly correlated with fertility status.

Controversy and Consensus on the Management of Elevated Sperm DNA Fragmentation in Male Infertility: A Global Survey, Current Guidelines, and Expert Recommendations

PURPOSE

Sperm DNA fragmentation (SDF) has been associated with male infertility and poor outcomes of assisted reproductive technology (ART). The purpose of this study was to investigate global practices related to the management of elevated SDF in infertile men, summarize the relevant professional society recommendations, and provide expert recommendations for managing this condition.

MATERIALS AND METHODS

An online global survey on clinical practices related to SDF was disseminated to reproductive clinicians, according to the CHERRIES checklist criteria. Management protocols for various conditions associated with SDF were captured and compared to the relevant recommendations in professional society guidelines and the appropriate available evidence. Expert recommendations and consensus on the management of infertile men with elevated SDF were then formulated and adapted using the Delphi method.

RESULTS

A total of 436 experts from 55 different countries submitted responses. As an initial approach, 79.1% of reproductive experts recommend lifestyle modifications for infertile men with elevated SDF, and 76.9% prescribe empiric antioxidants. Regarding antioxidant duration, 39.3% recommend 4-6 months and 38.1% recommend 3 months. For men with unexplained or idiopathic infertility, and couples experiencing recurrent miscarriages associated with elevated SDF, most respondents refer to ART 6 months after failure of conservative and empiric medical management. Infertile men with clinical varicocele, normal conventional semen parameters, and elevated SDF are offered varicocele repair immediately after diagnosis by 31.4%, and after failure of antioxidants and conservative measures by 40.9%. Sperm selection techniques and testicular sperm extraction are also management options for couples undergoing ART. For most questions, heterogenous practices were demonstrated.

CONCLUSIONS

This paper presents the results of a large global survey on the management of infertile men with elevated SDF and reveals a lack of consensus among clinicians. Furthermore, it demonstrates the scarcity of professional society guidelines in this regard and attempts to highlight the relevant evidence. Expert recommendations are proposed to help guide clinicians.

The effect of zinc supplementation on improving sperm parameters in infertile diabetic men

Background and aims

Diabetes mellitus (DM) may have different adverse effects on the male reproductive system. Zinc (Zn) is one of the necessary elements in the human and mammalian diet that plays an important role in scavenging reactive oxygen species (ROS) by providing antioxidant and anti-apoptotic properties. The aim of this study was to determine the protective effects of zinc supplements on sperm chromatin and the evaluation of sperm deoxyribonucleic acid (DNA) integrity in diabetic men.

Methods

In this interventional study, 43 infertile Iranian men in diabetic and non-diabetic groups were included. They were then randomly divided into two subgroups: normal saline intake and zinc sulfate intake (25 mg orally for 64 days each). Different indices of sperm analysis (number, morphology and motility) and testosterone levels were evaluated in four groups. Protamine deficiency and DNA fragmentation were assessed using chromomycin A3 (CMA3) and sperm chromatin dispersion (SCD) methods, respectively.

Results

Zinc supplementation reduced the deformity of neck and head of sperms (p < 0.05), as well as deformity of sperm tail in infertile diabetic men. Zinc administration ameliorated sperm motility types A, B and C (p < 0.05). Moreover, zinc administration reduced abnormal morphology and DNA fragmentation of sperms, which increased the SCD1 and SCD2 and reduced the SCD3 and SCD4 in both treated groups.

Conclusion

Zinc supplementation, as a powerful complement, is able to balance the effect of diabetes on sperm parameters, sperm chromatin and DNA integrity. Consequently, zinc supplementation can probably be considered a supportive compound in the diet of diabetic infertile men.

Semen processing using magnetic-activated cell sorting before ICSI is deemed safe for obstetric and perinatal outcomes: a retrospective multicentre study

RESEARCH QUESTION

Is magnetic-activated cell sorting (MACS) a safe semen sample processing technique for newborns and mothers when used for semen processing prior to intracytoplasmic sperm injection (ICSI) cycles?

DESIGN

This retrospective multicentre cohort study involved patients undergoing ICSI cycles with either donor or autologous oocytes from January 2008 to February 2020. They were divided into two groups: those who underwent standard semen preparation (reference group) and those who had an added MACS procedure (MACS group). A total of 25,356 deliveries were assessed in the case of cycles using donor oocytes, and 19,703 deliveries from cycles using autologous oocytes. Of these, 20,439 and 15,917, respectively, were singleton deliveries. Obstetric and perinatal outcomes were retrospectively assessed. All means, rates and incidences were computed per live newborn in each study group.

RESULTS

There were no significant differences between the main obstetric and perinatal morbidities affecting the mothers' and newborns' well-being between groups using either donated or autologous oocytes. There was a significant increase in the incidence of gestational anaemia in both subpopulations (donor oocytes P = 0.01; autologous oocytes P < 0.001). However, this incidence was within the estimated prevalence for gestational anaemia in the general population. There was a statistically significant decrease in preterm (P = 0.02) and very preterm (P = 0.01) birth rates in the MACS group in cycles using donor oocytes.

CONCLUSIONS

The use of MACS during semen preparation before ICSI using either donor or autologous oocytes appears to be safe for the mothers' and newborns' well-being during pregnancy and birth. Nevertheless, a close follow-up of these parameters in the future is advised, especially concerning anaemia, in order to detect even smaller effect sizes.

The use of ICSI in ART: evidence for practice

This article reviews the evidence regarding the safety and efficacy of intra-cytoplasmic sperm injection (ICSI). It provides evidence-based clinical and laboratory guidelines and recommendations for use of ICSI within an assisted reproductive technology (ART) service. The guidelines address the evidence for the use of ICSI rather than conventional IVF (cIVF); the use of ART techniques supplementary to ICSI; and risks associated with ICSI. This article is not intended to be the only approved standard of practice or to dictate an exclusive course of treatment. Other plans of management may be appropriate, taking into account the needs and medical history of the patient, available resources, and institutional or clinical practice limitations.

The Renaissance of Male Infertility Management in the Golden Age of Andrology

Infertility affects nearly 186 million people worldwide and the male partner is the cause in about half of the cases. Meta-regression data indicate an unexplained decline in sperm concentration and total sperm count over the last four decades, with an increasing prevalence of male infertility. This suggests an urgent need to implement further basic and clinical research in Andrology. Andrology developed as a branch of urology, gynecology, endocrinology, and, dermatology. The first scientific journal devoted to andrological sciences was founded in 1969. Since then, despite great advancements, andrology has encountered several obstacles in its growth. In fact, for cultural reasons, the male partner has often been neglected in the diagnostic and therapeutic workup of the infertile couple. Furthermore, the development of assisted reproductive techniques (ART) has driven a strong impression that this biotechnology can overcome all forms of infertility, with a common belief that having a spermatozoon from a male partner (a sort of sperm donor) is all that is needed to achieve pregnancy. However, clinical practice has shown that the quality of the male gamete is important for a successful ART outcome. Furthermore, the safety of ART has been questioned because of the high prevalence of comorbidities in the offspring of ART conceptions compared to spontaneous conceptions. These issues have paved the way for more research and a greater understanding of the mechanisms of spermatogenesis and male infertility. Consequently, numerous discoveries have been made in the field of andrology, ranging from genetics to several "omics" technologies, oxidative stress and sperm DNA fragmentation, the sixth edition of the WHO manual, artificial intelligence, management of azoospermia, fertility in cancers survivors, artificial testis, 3D printing, gene engineering, stem cells therapy for spermatogenesis, and reconstructive microsurgery and seminal microbiome. Nevertheless, as many cases of male infertility remain idiopathic, further studies are required to improve the clinical management of infertile males. A multidisciplinary strategy involving both clinicians and scientists in basic, translational, and clinical research is the core principle that will allow andrology to overcome its limits and reach further goals. This state-of-the-art article aims to present a historical review of andrology, and, particularly, male infertility, from its "Middle Ages" to its "Renaissance", a golden age of andrology.

The Impact of a Very Short Abstinence Period on Assisted Reproductive Technique Outcomes: A Systematic Review and Meta-Analysis

BACKGROUND

Previous studies supported the beneficial effects of a very short abstinence period on sperm quality. This systematic review and meta-analysis aimed to evaluate the effects of a very short abstinence period (within 4 h) on assisted reproductive technique (ART) outcomes.

METHODS

A literature search was performed using the Pubmed, Scopus, Web of Science, and Cochrane databases. A meta-analysis was performed according to the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) for randomized controlled trials (RCTs). All eligible studies were selected following the PICOS (Population, Intervention, Comparison/Comparator, Outcomes, Study type) model. The following pregnancy outcomes after ART were considered: fertilization rate (FR), implantation rate (IR), clinical pregnancy rate (CPR), live birth rate (LBR), and miscarriage rate (MR). This study was registered on PROSPERO (CRD42023396429).

RESULTS

We evaluated 414 records for eligibility, and 7 studies were ultimately included. Our analysis showed that a very short abstinence period significantly increased the IR, CPR, and LBR after ART. No significant differences were found for the FR and MR.

CONCLUSIONS

A second ejaculation collected very shortly after the first one could represent a simple strategy to improve the results of ART, especially in couples including patients with abnormal sperm parameters.

Machine learning-based clustering to identify the combined effect of the DNA fragmentation index and conventional semen parameters on in vitro fertilization outcomes

BACKGROUND

Previous studies have demonstrated an association between male sperm quality and assisted reproduction outcomes, focusing on the effects of individual parameters and reaching controversial conclusions. The WHO 6th edition manual highlights a new semen assay, the sperm DNA fragmentation index, for use after routine semen examination. However, the combined effect of the sperm DNA fragmentation index (DFI) and routine semen parameters remains largely unknown.

METHODS

We assessed the combined effect of the sperm DFI and conventional semen parameters on single fresh conventional IVF outcomes for infertile couples from January 1, 2017, to December 31, 2020. IVF outcomes were obtained from the cohort database follow-up records of the Clinical Reproductive Medicine Management System of the Third Affiliated Hospital of Guangzhou Medical University. An unsupervised K-means clustering method was applied to classify participants into several coexposure pattern groups. A multivariate logistic regression model was used for statistical analysis.

RESULTS

A total of 549 live births among 1258 couples occurred during the follow-up period. A linear exposure-response relationship was observed among the sperm DFI, sperm motility, and IVF outcomes. In multivariable adjustment, increased sperm DFI values and decreased sperm motility and semen concentration levels were associated with reduced odds of favourable IVF outcomes. Four coexposure patterns were generated based on the sperm DFI and the studied semen parameters, as follows: Cluster 1 (low sperm DFI values and high sperm motility and semen concentration levels), Cluster 2 (low sperm DFI values and moderate sperm motility and semen concentration levels), Cluster 3 (low sperm DFI values and low sperm motility and semen concentration levels) and Cluster 4 (high sperm DFI values and low sperm motility and semen concentration levels). Compared with those in Cluster 1, participants in Cluster 3 and Cluster 4 had lower odds of a live birth outcome, with odds ratios (95% confidence intervals [CIs]) of 0.733 (0.537, 0.998) and 0.620 (0.394, 0.967), respectively.

CONCLUSIONS

When combined with low sperm DFI values, there was no significant difference between high or moderate sperm concentration and motility levels, and both were associated with favourable IVF outcomes. Low sperm parameter levels, even when DFI values remain low, may still lead to poor IVF outcomes. Participants with high sperm DFI values and low sperm motility and semen concentration levels had the worst outcomes. Our findings offer a novel perspective for exploring the joint effects of sperm DFI and routine semen parameter values.

The Influence of Male Ejaculatory Abstinence Time on Pregnancy Rate, Live Birth Rate and DNA Fragmentation: A Systematic Review

Variation in ejaculatory abstinence time and its influence on semen quality and clinical reproductive outcomes is a growing concern among clinicians and researchers. The WHO (World Health Organization) recommends 2–7 days of abstinence time prior to semen collection for diagnostic purposes; however, the evidence that such an abstinence period leads to better pregnancy outcomes remains unclear. The aim of this systematic review is to evaluate short and long ejaculatory abstinence time in association with pregnancy rate, live birth rate and DNA fragmentation, in order to make a recommendation on an ideal timeframe for ejaculatory abstinence. This review is conducted according to the PRISMA guidelines and registered in PROSPERO (CRD42022379039). The electronic databases PubMed, Embase and Cochrane were searched for eligible studies. The Scottish Intercollegiate Guidelines Network was used for the assessment of the risk of bias across the included studies. Twenty-four studies were included in this systematic review. The included studies confirm that a shorter abstinence time is associated with improved pregnancy rates and live birth rates following assisted reproductive technology compared with longer ejaculatory abstinence times at different cut-off points. Similarly, a lower DNA fragmentation index was reported in semen analyses collected from short abstinence times compared with long abstinence times. However, due to the heterogeneity of the included studies, it is not possible to extract an ideal time of ejaculatory abstinence, but all outcomes improved with shorter ejaculatory abstinence times. This systematic review confirms that short ejaculatory abstinence times, less than those recommended by the WHO for diagnostic purposes, are associated with higher pregnancy and live birth rates and improved DNA fragmentation, when compared to long ejaculatory abstinence times.

Sperm DNA Damage and Its Relevance in Fertility Treatment: A Review of Recent Literature and Current Practice Guidelines

Sperm deoxyribonucleic acid (DNA) damage has recently emerged as one of the most controversial topics in male reproductive medicine. While level I evidence indicates that abnormal sperm DNA damage has substantial adverse effects on reproductive outcomes (including chance of pregnancy and risk of miscarriage), there is limited consensus on how sperm DNA fragmentation (SDF) testing should be performed and/or interpreted in clinical practice. In this article, we review: (1) how SDF is assessed, (2) cumulative evidence regarding its impact on reproductive outcomes, (3) methods for mitigating high SDF, and (4) the most recent practice guidelines available for clinicians regarding the use and interpretation of SDF testing.

The contemporary role of varicocele repair: why operate when in-vitro fertilization results are so good?

PURPOSE OF REVIEW

A male factor is either the primary cause or is contributory in at least half of all couples with infertility. Currently, many male factor problems may be disregarded, as reproductive technology has advanced so much that in-vitro fertilization (IVF)/Intracytoplasmic sperm injection (ICSI) allows the use of even a single sperm to achieve pregnancy.

RECENT FINDINGS

Varicocele is the most commonly diagnosed correctable cause. Microsurgical repair is considered the gold standard for repair. Research has shown that varicocele repair can impact the outcome of reproductive management and upgrade male infertility from adoption or donor sperm only to IVF/ICSI and microTESE, or IVF/ICSI with ejaculated sperm, or from IVF/ICSI to intrauterine insemination (IUI) or often naturally conceived.

SUMMARY

Varicocele diagnosis and repair is an essential part of infertility evaluation. Not only does it potentially impact antiretroviral therapy choices, but it can also increase testosterone levels benefiting long-term male health.

Sperm DNA fragmentation testing in clinical management of reproductive medicine

Background

Approximately 8%-12% of couples worldwide face infertility, with infertility of individuals assigned male at birth (AMAB) contributing to at least 50% of cases. Conventional semen analysis commonly used to detect sperm abnormalities is insufficient, as 30% of AMAB patients experiencing infertility show normal results in this test. From a genetic perspective, the assessment of sperm DNA fragmentation (SDF) is important as a parameter of sperm quality.

Methods

In this narrative study, we review and discuss pathophysiological causes, DNA repair mechanisms, and management of high SDF. We then summarize literature exploring the association between SDF and reproductive outcomes.

Main Findings

Recent systematic reviews and meta-analyses have revealed a significant association between high SDF in AMAB individuals and adverse reproductive outcomes including embryo development, natural conception, intrauterine insemination, and in vitro fertilization. However, the association with live birth rates and pregnancy rates following intracytoplasmic injection remains inconclusive. The disparities among quantitative assays, inconsistent reference range values, absent high-quality prospective clinical trials, and clinical heterogeneity in AMAB patients with elevated SDF represent the main limitations affecting SDF testing.

Conclusion

The evaluation and management of SDF plays an important role in a subset of AMAB infertility, but widespread integration into clinical guidelines will require future high-quality clinical trials and assay standardization.

The role of spermatozoa-zona pellucida interaction in selecting fertilization-competent spermatozoa in humans

Human fertilization begins when a capacitated spermatozoon binds to the zona pellucida (ZP) surrounding a mature oocyte. Defective spermatozoa-ZP interaction contributes to male infertility and is a leading cause of reduced fertilization rates in assisted reproduction treatments (ARTs). Human ejaculate contains millions of spermatozoa with varying degrees of fertilization potential and genetic quality, of which only thousands of motile spermatozoa can bind to the ZP at the fertilization site. This observation suggests that human ZP selectively interacts with competitively superior spermatozoa characterized by high fertilizing capability and genetic integrity. However, direct evidence for ZP-mediated sperm selection process is lacking. This study aims to demonstrate that spermatozoa-ZP interaction represents a crucial step in selecting fertilization-competent spermatozoa in humans. ZP-bound and unbound spermatozoa were respectively collected by a spermatozoa-ZP coincubation assay. The time-course data demonstrated that ZP interacted with a small proportion of motile spermatozoa. Heat shock 70 kDa protein 2 (HSPA2) and sperm acrosome associated 3 (SPACA 3) are two protein markers associated with the sperm ZP-binding ability. Immunofluorescent staining indicated that the ZP-bound spermatozoa had significantly higher expression levels of HSPA2 and SPACA3 than the unbound spermatozoa. ZP-bound spermatozoa had a significantly higher level of normal morphology, DNA integrity, chromatin integrity, protamination and global methylation when compared to the unbound spermatozoa. The results validated the possibility of applying spermatozoa-ZP interaction to select fertilization-competent spermatozoa in ART. This highly selective interaction might also provide diagnostic information regarding the fertilization potential and genetic qualities of spermatozoa independent of those derived from the standard semen analysis.

Localization Patterns of RAB3C Are Associated with Murine and Human Sperm Formation

Background and Objectives: Septins (SEPTs) are highly conserved GTP-binding proteins and the fourth component of the cytoskeleton. Polymerization of SEPTs contributes to several critical cellular processes such as cytokinesis, cytoskeletal remodeling, and vesicle transportation. In our previous study, we found that SEPT14 mutations resulted in teratozoospermia with >87% sperm morphological defects. SEPT14 interactors were also identified through proteomic assays, and one of the peptides was mapped to RAB3B and RAB3C. Most studies on the RAB3 family have focused on RAB3A, which regulates the exocytosis of neurotransmitters and acrosome reactions. However, the general expression and patterns of the RAB3 family members during human spermatogenesis, and the association between RAB3 and teratozoospermia owing to a SEPT14 mutation, are largely unknown. Materials and Methods: Human sperm and murine male germ cells were collected in this study and immunofluorescence analysis was applied on the collected sperm. Results: In this study, we observed that the RAB3C transcripts were more abundant than those of RAB3A, 3B, and 3D in human testicular tissues. During human spermatogenesis, the RAB3C protein is mainly enriched in elongated spermatids, and RAB3B is undetectable. In mature human spermatozoa, RAB3C is concentrated in the postacrosomal region, neck, and midpiece. The RAB3C signals were delocalized within human spermatozoa harboring the SEPT14 mutation, and the decreased signals were accompanied by a defective head and tail, compared with the healthy controls. To determine whether RAB3C is involved in the morphological formation of the head and tail of the sperm, we separated murine testicular tissue and isolated elongated spermatids for further study. We found that RAB3C is particularly expressed in the manchette structure, which assists sperm head shaping at the spermatid head, and is also localized at the sperm tail. Conclusions: Based on these results, we suggest that the localization of RAB3C proteins in murine and human sperm is associated with SEPT14 mutation-induced morphological defects in sperm.

Sperm DNA fragmentation negatively influences the cumulative live birth rate in the intracytoplasmic sperm injection cycles of couples with unexplained infertility

Objective: This study aimed to determine the effect of sperm DNA fragmentation (SDF) on the cumulative live birth rate (CLBR) in intracytoplasmic sperm injection (ICSI) cycles in couples with unexplained infertility.Methods: We conducted a prospective study of 145 couples who underwent ICSI cycles for unexplained infertility. Based on the SDF rate, patients were categorized into a low SDF group (SDF ≤30%, n=97) and a high SDF group (SDF >30%, n=48). SDF was assessed using the acridine orange test on density gradient centrifugation prepared samples. The CLBR was calculated as the first live birth event per woman per egg collection over 2 years.Results: The high SDF group (SDF >30%) showed a significantly lower CLBR (p<0.05) and a significantly higher miscarriage rate (p<0.05) than the low SDF group (SDF ≤30%). No significant difference was observed in the implantation and cumulative pregnancy rates between the two SDF groups. The total number of embryo transfers was stratified further into fresh and frozen embryo transfers. In the fresh embryo transfers, there were significant differences in the implantation rates, clinical pregnancy rates, and live birth rates (p<0.05) between the low SDF and high SDF groups. However, in the frozen embryo transfers, there were no significant differences in clinical outcomes between the two groups. In the multivariable logistic regression analysis, SDF was a predictor of CLBR (p<0.05) when adjusted for possible confounding factors.Conclusion: High SDF was associated with a lower CLBR and a higher miscarriage rate in the ICSI cycles of couples with unexplained infertility.

Efficacy of density gradient centrifugation technique (DGC) in enhancing sperm cell DNA quality for assisted reproductive technique

Objective

Density gradient centrifugation (DGC) is commonly used for sperm preparation before assisted reproductive technology (ART) procedures. This technique separates superior motile spermatozoa with normal morphology from the total sperm population. However, there is still controversy as to the effects of this sperm separation technique on sperm cell DNA integrity which is a determining element in the process of fertilization and embryonic development.

The objective of this study was to determine the effects of DGC on sperm cell DNA integrity as assessed by a novel association between two cytogenetic tests.

Study designs

Semen samples were collected from 30 fertile donors and 40 patients being candidates for ART treatment. Each sample was divided into two parts: the first portion was subjected to selection by two layers of DGC (45% and 90%) and the second fraction was rinsed with phosphate-buffered saline solution and centrifuged without density gradient.

Abnormal sperm chromatin structure as evaluated by a sperm chromatin dispersion (SCD) test and DNA denaturation as assessed by an acridine orange (AO) test were monitored in the initially washed sample and in the different layers of the density gradient centrifugation.

Results

DGC significantly improved the proportion of sperm progressive motility, total motility, and sperm morphology. Moreover, following density gradient centrifugation, the proportion of spermatozoa with denaturated DNA significantly decreased when compared with whole semen (p < 0.001). In addition, we found that spermatozoa isolated in the 90% layer possessed a significantly lower percentage of sperm chromatin decondensation when compared with those remaining in the 45% layer and unprocessed semen (p < 0.001).

Conclusions

Using double cytogenetic tests, our study shows that semen processing by density gradient centrifugation is useful in selecting sperm with higher double-strand DNA integrity and recommended to be used in sperm preparation for assisted reproduction.

The role of sperm DNA integrity in couples with recurrent implantation failure following IVF treatment

There is increasing evidence from the literature that indicates the association between impaired sperm DNA integrity and male infertility. However, the data is insufficient regarding recurrent implantation failure (RIF) and sperm DNA damage. This study aimed to investigate the association between sperm DNA fragmentation and RIF cases. Basic semen parameters and sperm DNA fragmentation index (DFI) of men whose partner was suffering from RIF were compared with men whose partner was diagnosed with unexplained infertility (UEI) but had clinical pregnancies following IVF treatment. A retrospective analysis from a large-volume IVF center has been performed, and a total of 197 couples underwent analysis. Two groups were formed, couples with RIF and couples diagnosed with UEI but had clinical pregnancies (controls) following IVF cycles. The mean number of cycles showed significant differences between the groups. However, no statistical difference was observed between RIF and the control group regarding patient characteristics, semen parameters, and sperm DNA fragmentation index (DFI). Also, no statistically significant correlation was found between sperm DFI and clinical pregnancies in the unexplained infertility cohort. Our results show that sperm DNA fragmentation may not be an important contributing factor to RIF cases.

Sperm selection with hyaluronic acid improved live birth outcomes among older couples and was connected to sperm DNA quality, potentially affecting all treatment outcomes

STUDY QUESTION

What effects did treatment using hyaluronic acid (HA) binding/selection prior to ICSI have on clinical outcomes in the Hyaluronic Acid Binding sperm Selection (HABSelect) clinical trial?

SUMMARY ANSWER

Older women randomized to the trial's experimental arm (selection of sperm bound to immobilized (solid-state) HA) had the same live birth rates as younger women, most likely a result of better avoidance of sperm with damaged DNA.

WHAT IS KNOWN ALREADY

Recent randomized controlled trials (RCTs) investigating the efficacy of HA-based sperm selection prior to ICSI, including HABSelect, have consistently reported reductions in the numbers of miscarriages among couples randomized to the intervention, suggesting a pathological sperm-mediated factor mitigated by prior HA-binding/selection. The mechanism of that protection is unknown.

STUDY DESIGN, SIZE, DURATION

The original HABSelect Phase 3 RCT ran from 2014 to 2017 and included 2752 couples from whom sperm samples used in control (ICSI) and intervention (Physiological IntraCytoplasmic Sperm Injection; PICSI) arms of the trial were stored frozen for later assessment of DNA quality (DNAq). The trial overlapped with its mechanistic arm, running from 2016 to 2018.

PARTICIPANTS/MATERIALS, SETTING, METHODS

As miscarriage reduction was a significant secondary outcome of the trial, samples (n = 1247) selected for the mechanistic analysis were deliberately enriched for miscarriage outcomes (n = 92 or 7.4%) from a total of 154 miscarriages (5.6%) among all (n = 2752) couples randomized by stratified random sampling. Values from fresh semen samples for sperm concentration (mml), percentage forward progressive motility and percentage HA-binding score (HBS) were obtained before being processed by differential density gradient centrifugation or (rarely) by swim-up on the day of treatment. Surplus sperm pellets were recovered, aliquoted and cryopreserved for later analysis of DNAq using slide-based Comet, TUNEL, acridine orange (AO) and the sperm chromatin dispersion (SCD) assays. Following their classification into normal and abnormal sample subcategories based on reference values for sperm concentration and motility, relationships with HBS and DNAq were examined by Spearman correlation, Student's t-tests, Mann Whitney U tests, and logistic regression (univariable and multivariable). Parsimonious selection enabled the development of models for exploring and explaining data trends. Potential differences in future cumulative pregnancy rates relating to embryo quality were also explored.

MAIN RESULTS AND THE ROLE OF CHANCE

Results from the 1247 sperm samples assayed for HBS and/or DNAq, generated data that were considered in relation to standard physiological measures of (sperm) vitality and to treatment outcomes. All measures of HBS and DNAq discriminated normal from abnormal sperm samples (P < 0.001). SCD correlated negatively with the Comet (r = -0.165; P < 0.001) and TUNEL assays (r = -0.200; P < 0.001). HBS correlated negatively with AO (r = -0.211; P < 0.001), Comet (r = -0.127; P < 0.001) and TUNEL (r = -0.214; P < 0.001) and positively with SCD (r = 0.255; P < 0.001). A model for predicting live birth (and miscarriage) rates included treatment allocation (odds ratio: OR 2.167, 95% CI 1.084-4.464, P = 0.031), female age (OR 0.301, 95% CI 0.133-0.761, P = 0.013, per decade) and the AO assay (OR 0.79, 95% CI 0.60-1. 02.761, P = 0.073, per 10 points rise). A model predicting the expected rate of biochemical pregnancy included male age (OR 0.464, 95% CI 0.314-0.674, P < 0.001, per decade) and the SCD assay (OR 1.04, 95% CI 1.007-1.075, P = 0.018, per 10 point rise). A model for conversion from biochemical to clinical pregnancy did not retain any significant patient or assay variables. A model for post-injection fertilization rates included treatment allocation (OR 0.83, 95% CI 0.75-0.91, P < 0.001) and the Comet assay (OR 0.950, 95% CI 0.91-1.00, P = 0.041).

LIMITATIONS, REASONS FOR CAUTION

HABSelect was a prospective RCT and the mechanistic study group was drawn from its recruitment cohort for retrospective analysis, without the full benefit of randomization. The clinical and mechanistic aspects of the study were mutually exclusive in that measures of DNAq were obtained from residual samples and not from HA-selected versus unselected sperm. Models for fitting mechanistic with baseline and other clinical data were developed to compensate for variable DNAq data quality. HABSelect used a solid-state version of PICSI and we did not assess the efficacy of any liquid-state alternatives. PICSI reduced fertilization rates and did not improve the outlook for cumulative pregnancy rates.

WIDER IMPLICATIONS OF THE FINDINGS

Notwithstanding the interventional effect on fertilization rates and possibly blastocyst formation (neither of which influenced pregnancy rates), poor sperm DNAq, reflected by lower HBS, probably contributed to the depression of all gestational outcomes including live births, in the HABSelect trial. The interventional avoidance of defective sperm is the best explanation for the equalization in live birth rates among older couples randomized to the trial's PICSI arm. As patients going forward for assisted conception cycles globally in future are likely to be dominated by an older demographic, HA-based selection of sperm for ICSI could be considered as part of their treatment plan.

STUDY FUNDING/COMPETING INTEREST(S)

The study was supported by the National Institute for Health Research (NIHR) EME (Efficacy and Mechanism Evaluation)-11-14-34. National Research Ethics Service approval 11/06/2013: 13/YH/0162. S.L. is CEO of ExamenLab Ltd (company number NI605309).

TRIAL REGISTRATION NUMBER

ISRCTN99214271.

Sperm deoxyribonucleic acid fragmentation (by terminal deoxynucleotidyl transferase biotin dUTP nick end labeling assay) does not impair reproductive success measured as cumulative live birth rates per donor metaphase II oocyte used

OBJECTIVE

To better study the effect of sperm deoxyribonucleic acid fragmentation (SDF) on intracytoplasmic sperm injection (ICSI) outcomes from an ovum donation program by assessing the cumulative live birth rates (CLBRs) per number of embryo transfers (ETs), embryos replaced (EmbR), and metaphase II (MII) oocytes required in consecutive treatments to achieve the first newborn.

DESIGN

A multicenter retrospective cohort study was conducted, and the Kaplan-Meier survival curves were generated to calculate the CLBR with regard to the SDF degree.

SETTING

Private university-affiliated in vitro fertilization centers.

PATIENT(S)

Data from 864 couples using donated eggs and undergoing ICSI from 2000 to 2019 were analyzed. Sperm deoxyribonucleic acid fragmentation was measured using terminal deoxynucleotidyl transferase biotin dUTP nick end labeling assay on their ejaculated sperm.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Live birth rate (LBR) per first ET and per all consecutive ETs within the same patient and CLBR per ET, per EmbR, and per MII oocyte used considering the SDF level.

RESULT(S)

A total of 1,903 ICSI cycles were considered, encompassing 6,340 donated oocytes, 2,543 embryos, and 1,145 ETs. Comparing ≤15% SDF (low) with >15% SDF (high) or by 10% SDF ranges, the LBRs per first ET and per all ETs did not significantly differ. The Kaplan-Meier curves of the CLBR per ET, per EmbR, and per donor oocyte consumed were similar between the SDF groups evaluated.

CONCLUSION(S)

Elevated SDF does not reduce the LBR or cumulative probability to obtain a child when calculated per ET, per EmbR, and per donated MII oocyte used in couples undergoing ICSI cycles.

Sperm DNA integrity is critically impacted by male age but does not influence outcomes of artificial insemination by husband in the Chinese infertile couples

The sperm chromatin structure assay (SCSA) is crucial for assessing male fertility. However, the predictive value of the SCSA parameters, including the DNA fragment indices (DFI) and the percentages of high DNA stainability (HDS), for outcomes of artificial insemination by husband (AIH) remains controversial. This study aims to evaluate the correlations between SCSA parameters and male aging as well as other routine semen parameters, and explore their prognostic powers on AIH outcomes of the Chinese infertile couples. A total of 809 AIH cycles were retrospectively analyzed. The results showed that DFI in the age groups < 35 years were significantly lower than that in the age groups ≥ 35 years (P < 0.001). Meanwhile, there was no statistical difference in HDS between the age groups (P = 0.063). DFI and HDS are negatively correlated with most routine semen parameters (all P < 0.05). The chi-square and generalized linear model tests indicated that neither DFI nor HDS influenced the clinical pregnancy rate of AIH. In summary, this study found that aging is a critical factor leading to increased sperm DFI but not HDS. DFI and HDS are negatively correlated with most semen parameters but do not significantly influence AIH outcomes.

New Insight on the In Vitro Effects of Melatonin in Preserving Human Sperm Quality

Spermatozoa (SPZ) are sensitive to stressful conditions, particularly oxidative stress, which alters their quality; thus, the use of protective molecules as an antioxidant is encouraged. Herein, we used melatonin (MLT) to investigate its in vitro effects on human sperm parameters under conditions of oxidative stress induced by cadmium (Cd). Fifteen human semen samples were divided into control, Cd-treated, MLT-treated, and Cd+MLT-treated groups and analyzed after 30 min, 6 h, and 24 h of exposure. Results showed a time-dependent decrease in SPZ motility, DNA integrity, and increased apoptosis induced by oxidative stress, and these effects were counteracted by MLT co-treatment. Based on these data, we further explored additional parameters just at 24 h. The induced oxidative stress, highlighted by the increased lipid peroxidation, reduced the percentage of SPZ able to undertake acrosome reaction and altered the levels and localization of some protein markers of motility (PREP, RSPH6A), morphology (DAAM1), and acrosome membrane (PTMA, IAM38); all these effects were counteracted by MLT co-treatment. Interestingly, MLT alone was able to ameliorate motility at 30 min of incubation compared to the control, while at 24 h, it prevented the physiological alteration in terms of motility, DNA integrity, and apoptosis. Collectively, the data encourage MLT use as an integrative molecule to ameliorate human gamete quality when compromised by stressful conditions.

Antioxidants for male subfertility

BACKGROUND

The inability to have children affects 10% to 15% of couples worldwide. A male factor is estimated to account for up to half of the infertility cases with between 25% to 87% of male subfertility considered to be due to the effect of oxidative stress. Oral supplementation with antioxidants is thought to improve sperm quality by reducing oxidative damage. Antioxidants are widely available and inexpensive when compared to other fertility treatments, however most antioxidants are uncontrolled by regulation and the evidence for their effectiveness is uncertain. We compared the benefits and risks of different antioxidants used for male subfertility.

OBJECTIVES

To evaluate the effectiveness and safety of supplementary oral antioxidants in subfertile men.

SEARCH METHODS

The Cochrane Gynaecology and Fertility (CGF) Group trials register, CENTRAL, MEDLINE, Embase, PsycINFO, AMED, and two trial registers were searched on 15 February 2021, together with reference checking and contact with experts in the field to identify additional trials.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared any type, dose or combination of oral antioxidant supplement with placebo, no treatment, or treatment with another antioxidant, among subfertile men of a couple attending a reproductive clinic. We excluded studies comparing antioxidants with fertility drugs alone and studies that included men with idiopathic infertility and normal semen parameters or fertile men attending a fertility clinic because of female partner infertility.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures recommended by Cochrane. The primary review outcome was live birth. Clinical pregnancy, adverse events and sperm parameters were secondary outcomes.

MAIN RESULTS

We included 90 studies with a total population of 10,303 subfertile men, aged between 18 and 65 years, part of a couple who had been referred to a fertility clinic and some of whom were undergoing medically assisted reproduction (MAR). Investigators compared and combined 20 different oral antioxidants. The evidence was of 'low' to 'very low' certainty: the main limitation was that out of the 67 included studies in the meta-analysis only 20 studies reported clinical pregnancy, and of those 12 reported on live birth. The evidence is current up to February 2021. Live birth: antioxidants may lead to increased live birth rates (odds ratio (OR) 1.43, 95% confidence interval (CI) 1.07 to 1.91, P = 0.02, 12 RCTs, 1283 men, I2 = 44%, very low-certainty evidence). Results in the studies contributing to the analysis of live birth rate suggest that if the baseline chance of live birth following placebo or no treatment is assumed to be 16%, the chance following the use of antioxidants is estimated to be between 17% and 27%. However, this result was based on only 246 live births from 1283 couples in 12 small or medium-sized studies. When studies at high risk of bias were removed from the analysis, there was no evidence of increased live birth (Peto OR 1.22, 95% CI 0.85 to 1.75, 827 men, 8 RCTs, P = 0.27, I2 = 32%). Clinical pregnancy rate: antioxidants may lead to increased clinical pregnancy rates (OR 1.89, 95% CI 1.45 to 2.47, P < 0.00001, 20 RCTs, 1706 men, I2 = 3%, low-certainty evidence) compared with placebo or no treatment. This suggests that, in the studies contributing to the analysis of clinical pregnancy, if the baseline chance of clinical pregnancy following placebo or no treatment is assumed to be 15%, the chance following the use of antioxidants is estimated to be between 20% and 30%. This result was based on 327 clinical pregnancies from 1706 couples in 20 small studies. Adverse events Miscarriage: only six studies reported on this outcome and the event rate was very low. No evidence of a difference in miscarriage rate was found between the antioxidant and placebo or no treatment group (OR 1.46, 95% CI 0.75 to 2.83, P = 0.27, 6 RCTs, 664 men, I2 = 35%, very low-certainty evidence). The findings suggest that in a population of subfertile couples, with male factor infertility, with an expected miscarriage rate of 5%, the risk of miscarriage following the use of an antioxidant would be between 4% and 13%. Gastrointestinal: antioxidants may lead to an increase in mild gastrointestinal discomfort when compared with placebo or no treatment (OR 2.70, 95% CI 1.46 to 4.99, P = 0.002, 16 RCTs, 1355 men, I2 = 40%, low-certainty evidence). This suggests that if the chance of gastrointestinal discomfort following placebo or no treatment is assumed to be 2%, the chance following the use of antioxidants is estimated to be between 2% and 7%. However, this result was based on a low event rate of 46 out of 1355 men in 16 small or medium-sized studies, and the certainty of the evidence was rated low and heterogeneity was high. We were unable to draw conclusions from the antioxidant versus antioxidant comparison as insufficient studies compared the same interventions.

AUTHORS' CONCLUSIONS

In this review, there is very low-certainty evidence from 12 small or medium-sized randomised controlled trials suggesting that antioxidant supplementation in subfertile males may improve live birth rates for couples attending fertility clinics. Low-certainty evidence suggests that clinical pregnancy rates may increase. There is no evidence of increased risk of miscarriage, however antioxidants may give more mild gastrointestinal discomfort, based on very low-certainty evidence. Subfertile couples should be advised that overall, the current evidence is inconclusive based on serious risk of bias due to poor reporting of methods of randomisation, failure to report on the clinical outcomes live birth rate and clinical pregnancy, often unclear or even high attrition, and also imprecision due to often low event rates and small overall sample sizes. Further large well-designed randomised placebo-controlled trials studying infertile men and reporting on pregnancy and live births are still required to clarify the exact role of antioxidants.

Oxidative Stress and Assisted Reproduction: A Comprehensive Review of Its Pathophysiological Role and Strategies for Optimizing Embryo Culture Environment

Oxidative stress (OS) due to an imbalance between reactive oxygen species (ROS) and antioxidants has been established as an important factor that can negatively affect the outcomes of assisted reproductive techniques (ARTs). Excess ROS exert their pathological effects through damage to cellular lipids, organelles, and DNA, alteration of enzymatic function, and apoptosis. ROS can be produced intracellularly, from immature sperm, oocytes, and embryos. Additionally, several external factors may induce high ROS production in the ART setup, including atmospheric oxygen, CO2 incubators, consumables, visible light, temperature, humidity, volatile organic compounds, and culture media additives. Pathological amounts of ROS can also be generated during the cryopreservation-thawing process of gametes or embryos. Generally, these factors can act at any stage during ART, from gamete preparation to embryo development, till the blastocyst stage. In this review, we discuss the in vitro conditions and environmental factors responsible for the induction of OS in an ART setting. In addition, we describe the effects of OS on gametes and embryos. Furthermore, we highlight strategies to ameliorate the impact of OS during the whole human embryo culture period, from gametes to blastocyst stage.

Extended semen examinations in the sixth edition of the World Health Organization manual on semen analysis: contributing to the understanding of the function of the male reproductive system

In the sixth edition of the World Health Organization manual for the examination and processing of human semen, extended examination methods to provide key diagnostics in the investigation of the male reproductive system function are elaborated. These go beyond the basic analysis of semen and may be useful in more specifically guiding the clinical characterization of fertile or infertile men. Among the extended examinations included in the chapter, the use of multiparametric scoring for sperm morphological defects, sperm DNA fragmentation, and the roles for computer-assisted analysis of sperm or semen are arguably those that will be the most widely used and may also cause the most debate.

Effects of paternal overnutrition and interventions on future generations

In the last two decades, evidence from human and animal studies suggests that paternal obesity around the time of conception can have adverse effects on offspring health through developmental programming. This may make significant contributions to the current epidemic of obesity and related metabolic and reproductive complications like diabetes, cardiovascular disease, and subfertility/infertility. To date, changes in seminal fluid composition, sperm DNA methylation, histone composition, small non-coding RNAs, and sperm DNA damage have been proposed as potential underpinning mechanism to program offspring health. In this review, we discuss current human and rodent evidence on the impact of paternal obesity/overnutrition on offspring health, followed by the proposed mechanisms, with a focus on sperm DNA damage underpinning paternal programming. We also summarize the different intervention strategies implemented to minimize effects of paternal obesity. Upon critical review of literature, we find that obesity-induced altered sperm quality in father is linked with compromised offspring health. Paternal exercise intervention before conception has been shown to improve metabolic health. Further work to explore the mechanisms underlying benefits of paternal exercise on offspring are warranted. Conversion to healthy diets and micronutrient supplementation during pre-conception have shown some positive impacts towards minimizing the impact of paternal obesity on offspring. Pharmacological approaches e.g., metformin are also being applied. Thus, interventions in the obese father may ameliorate the potential detrimental impacts of paternal obesity on offspring.

Role of female age in regulating the effect of sperm DNA fragmentation on the live birth rates in intracytoplasmic sperm injection cycles with own and donor oocytes

Background:

Sperm DNA integrity assessment has been progressively used as an unfettered measure of sperm as it proffers more prognostic and diagnostic information than routine semen analysis. The contentious effect of sperm DNA fragmentation (SDF) on clinical outcomes can be attributed to female factors such as age, oocyte quality and ovarian reserve.

Aims:

The study is mainly aimed to know the influence of SDF on the live birth rates in intracytoplasmic sperm injection (ICSI) cycles with own and donor oocytes. Second, to know the role of female age in regulating the effect of SDF on the live birth rates in ICSI cycles with own and donor oocytes.

Setting and Design:

A prospective cohort study was done at our tertiary care centre attached to the reproductive medicine unit in medical college.

Materials and Methods:

The study included 356 patients who underwent first ICSI cycles either with own or donor-oocytes along with day 5 fresh embryo transfers only. The main outcome measures were live birth rates and miscarriage rates.

Statistical Analysis Used:

Chi-squared test was used to compare the categorical variables between the groups. The receiver operating characteristic curve was developed to correlate the female age with the live birth rate.

Results:

A significant decrease in the live birth rates (42.85% vs. 26.15%, P = 0.023) and an increase in the miscarriage rates (12.30% vs. 34.61%, P = 0.013) were observed in the high-SDF group ICSI cycles of own-oocyte patients. However, there was no significant difference in the live birth rates and miscarriage rates in the low- and high-SDF groups of donor oocyte ICSI cycle patients (P > 0.05). The own-oocyte ICSI cycle patients were further stratified based on the female age. In the female age group ≤30 years there was no significant difference in the live birth and miscarriage rates (P > 0.05) similar to donor oocyte ICSI cycles. Whereas, there was a significant difference in the live birth rates in the females of age >30 years (13.79% vs. 34.37%, P = 0.040).

Conclusion:

In conclusion, high-SDF has a negative influence on the live birth rates and a positive influence on the miscarriage rates in patients with own-oocyte ICSI cycles. A similar influence was not observed in patients with donor-oocyte ICSI cycles and in young female patients (age ≤30 years) with own-oocyte ICSI cycles.

Sperm DNA fragmentation in reproductive medicine: A review

Approximately 15% of the world's couples suffer from infertility during their reproductive period of which the male factor is responsible for 50% of cases. Male factor infertility is multifactorial in origin, and sperm DNA fragmentation (SDF) has also been linked to male infertility including idiopathic male infertility. Some degree of controlled DNA nicking is essential for adequate DNA compaction, but excessive SDF is usually associated with reduced male fertility potential, reduced fertilisation, poor embryo quality, recurrent pregnancy loss and poor assisted reproductive techniques (ARTs) outcomes. Although semen analysis remains the gold standard for diagnosis of male factor infertility worldwide, its limitations motivated the search and the development of complementary tests of sperm function and integrity. SDF assay is an emerging diagnostic tool in infertile men, and several indications for SDF testing in infertile couples have also been proposed. The use of SDF in routine male infertility assessment is, however, still controversial. Furthermore, both direct and indirect SDF tests are now available. Hence, the present review was conducted to summarise the recent evidence of SDF, underlying mechanisms, clinical indications, diagnostic tests, as well as the role of SDF in male factor infertility, pregnancy and ART outcomes.

Beyond conventional sperm parameters: the role of sperm DNA fragmentation in male infertility

Infertility is a condition that widely affects the couples all over the world. In this regard, sperm DNA fragmentation can lead to harmful reproductive consequences, including male infertility and poor outcomes after assisted reproductive techniques. The investigation of SDF in male infertility diagnostics has constantly increased over time, becoming more common in clinical practice with the recent publication of several guidelines regarding its testing. This narrative review aims to provide a comprehensive overview of the pathogenesis and causes of sperm DNA fragmentation, as well as the assays which are more commonly performed for testing. Moreover, we discussed the most recently published evidence regarding the use of SDF testing in clinical practice, highlighting the implications of high sperm DNA fragmentation rate on human reproduction, and the therapeutic approaches for the clinical management of infertile patients. Our review confirms a significant harmful impact of sperm DNA fragmentation on reproduction, and points out several interventions which can be applied in clinics to reduce sperm DNA fragmentation and improve reproductive outcomes. Sperm DNA fragmentation has been shown to adversely impact male fertility potential. As high sperm DNA fragmentation levels have been associated with poor reproductive outcomes, its testing may significantly help clinicians in defining the best therapeutic strategy for infertile patients.

The relationship between genitourinary microorganisms and oxidative stress, sperm DNA fragmentation and semen parameters in infertile men

An imbalance in the genitourinary microbiome is emerging as a contributing factor to male infertility. The purpose of this study was to determine whether there is an association between genitourinary microorganisms and seminal oxidative stress, sperm DNA fragmentation and semen parameters. It included 770 men attending for diagnostic testing for subfertility. Genitourinary microorganisms were identified in 43.0% men; 20.1% had microorganisms in semen; 18.7% in urine; and 5.8% had microorganisms in urine and semen. Enterococcus faecalis was the most prevalent organism in semen (22.0% samples; 61.5% organisms) with Ureaplasma spp. (16.9% samples; 53.3% organisms) and Gardnerella vaginalis (11.4% samples; 37.4% organisms) most prevalent in urine. Semen parameters were unaffected by microorganisms (p > 0.05). Seminal ROS were significantly higher in men with microorganisms compared to those without (p < 0.001), particularly when present in both urine and semen (p < 0.01). Microorganisms were associated with significantly higher DNA fragmentation, irrespective of whether they were in semen or urine (p < 0.001). An imbalance in the genitourinary microbiome is associated with DNA damage and oxidative stress which may have considerable consequences for achieving an ongoing pregnancy. This highlights the need for incorporating genitourinary microorganism screening for all men as part of diagnostic evaluation prior to undergoing treatment for infertility.

Outcomes of Frozen Oocyte Donor In Vitro Fertilization (IVF) Cycles Using Fresh Versus Frozen Sperm

The ability to use frozen sperm for insemination during in vitro fertilization (IVF) is crucial for patients and for reproductive endocrinologists. However, concerns exist regarding the effects of cryopreservation on sperm quality and IVF outcomes. This study compares outcomes of frozen donor oocyte IVF cycles with intracytoplasmic sperm injection (ICSI) of good quality fresh versus frozen ejaculated sperm. Patients who underwent their first frozen donor oocyte IVF cycle between 2013 and 2019 at Mayo Clinic were identified. The primary outcome was live birth rate (LBR). Secondary outcomes included fertilization rate (FR), blastocyst development rate (BR), and clinical pregnancy rate (CPR). Twenty-six patients used fresh sperm and 19 patients utilized frozen sperm; there were no significant demographic differences between the groups. There were no significant differences noted in CPR, FR, and BR. Although the LBR was not statistically different when frozen versus fresh sperm was utilized (52.6% vs. 61.5%, p = 0.55), there was a distinct trend towards improved outcomes with fresh sperm that may be clinically significant. This data suggests that frozen sperm may be an alternative to a fresh sample, however fresh sperm may ultimately be a better option. This finding should be further explored with studies utilizing a larger sample size.

Does Microfluidic Sperm Sorting Affect Embryo Euploidy Rates in Couples with High Sperm DNA Fragmentation?

Male infertility contributes as the main factor in 30-50% of infertility cases. Conventional methods for sperm preparation have induced questioning of sperm recovery rates. The microfluidic sperm sorting (MSS) technique selects highly motile sperm with lower levels of SDF (sperm DNA fragmentation) compared to conventional sperm sorting techniques. This study aimed to determine whether utilizing this technique will reveal better embryo quality and euploidy rates in couples with repeated implantation failure (RIF) and high SDF in a new PGT-A (preimplantation genetic testing for aneuploidies) cycle. This retrospective study included couples referred to PGT-A for previous repeated ART (assisted reproductive techniques) cycle failures and with high SDF. In their new cycles, couples who accepted the technique were assigned to the MSS group, and the rest were managed with DGC (density-gradient centrifugation). Two groups were compared in terms of fertilization and euploidy rates, clinical miscarriage and live birth rates, the total number of blastocysts, and top quality blastocysts. There was no difference between the groups regarding fertilization rates, euploidy rates, clinical miscarriage, and live birth rates. The total number of blastocysts and top quality blastocysts were significantly higher in the MSS group. The MSS technique provides a higher number of top-quality blastocysts than DGC; however, neither euploidy nor live birth rates improved. Studies focusing on confounding factors to embryonic genomic status in the presence of high SDF are needed.

Sperm DNA Fragmentation

Sperm DNA fragmentation refers to the accumulation of adducts as well as single- or double-strand DNA breaks and reflects the sperm DNA quality. Current data suggest that there are differences in sperm DNA quality among individuals with high or low fertility, and this observation has led to the idea that testing sperm DNA fragmentation could be a useful test of male fertility. However, sperm DNA fragmentation has become one of the most frequently debated topics in reproductive medicine, as there is no agreement about the optimal way to test for DNA fragmentation, the clinically significant level of sperm DNA fragmentation, as well as the best therapeutic options for infertile men. This article presents current evidence related to sperm DNA fragmentation and its role in managing male infertility.