The Association of Sperm DNA Fragment and Assisted Reproductive Outcomes: A 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.

Sperm DNA fragmentation and infertility: a narrative review

PURPOSE

The purpose of this narrative review is to provide a practical understanding of sperm DNA fragmentation (SDF) in the management of male infertility.

METHODS

A search for systematic reviews and meta-analyses (SRMA) on SDF between April 1st, 2018 and April 1st, 2023 was performed using PubMed and articles were selected as per their relevance to the topic. Guidelines from major societies were also reviewed. Three clinical cases are reported and discussed.

RESULTS

The search initially identified 80 articles. We selected 13 SRMAs based on their relevance to the topic. Of the 13 SRMAs, 7 evaluated the effect of SDF on assisted reproductive technology (ART) outcomes and recurrent pregnancy loss, 3 studied the effect of varicocele repair on SDF, and 3 evaluated the role of SDF involving lifestyle and environmental health factors including body mass index and male factor treatment strategies.

CONCLUSION

Evidence suggests that increased SDF has a negative impact on natural pregnancy and ART outcomes. SDF testing may be particularly important in the infertility evaluation of men with varicoceles, idiopathic or unexplained infertility, recurrent pregnancy loss, or previous ART failure. Further studies are needed on SDF testing and the implications it can have on male factor infertility and pregnancy outcomes as well as its implementation in the setting of ART.

Comparison of Embryological Results of Microinjection in Two Groups of Men with and without Requesting Sperm DNA Fragmentation Index Measurement

Introduction

The sperm DNA fragmentation index (DFI) is considered a valuable measure to assess male fertility, but the predictive value of DFI for the outcomes in assisted reproductive technology (ART) is still controversial. Therefore, this study is aimed at investigating the effect of requesting a DFI test or performing ART without DFI on the results observed in the embryology laboratory (number of embryos, fertilization rate, and embryo quality) after intracytoplasmic sperm injection (ICSI).

Methods

This retrospective study was conducted on infertile men who underwent ICSI and were referred to the Avicenna Infertility and Recurrent Abortion Treatment Center in Tehran from 2019 to 2022. The samples were categorized into two groups: a case group with DFI measurement and a control group without DFI measurement. We conducted a comparative analysis of the embryology results between the two groups, focusing on parameters such as fertilization rate, number of embryos, and embryo quality. t-tests and Mann-Whitney U tests were used to conduct single variable analysis. Potential confounding effects were adjusted to use the multivariate linear and logistic regression.

Results

Data analysis showed no significant statistical difference between the case group and the control group in terms of the number of embryos (95% confidence interval for the regression coefficient (β) = -0.257-0.123), and embryo quality (95% confidence interval for β = -0.199-0.114). There was no significant statistical difference between the two groups due to the fertilization rate (95% confidence interval for β = -3.42-3.42), except for the variables of woman's age and sperm count after ICSI, as determined by adjusted linear regression.

Conclusions

Although DFI measurement is used to assess male infertility, its importance as a predictor for the embryology outcomes after ICSI requires further evaluation and the determination of a cut-off point for predicting results. This study was based on retrospectively collected DFI data, and prospective studies confirming the superiority of ICSI outcomes are necessary.

High sperm DNA fragmentation increased embryo aneuploidy rate in patients undergoing preimplantation genetic testing

RESEARCH QUESTION

Is high sperm DNA fragmentation (SDF) associated with a high embryonic aneuploidy rate in patients undergoing intracytoplasmic sperm injection (ICSI)-preimplantation genetic testing (PGT)?

DESIGN

This was a retrospective study of 426 couples with normal karyotypes undergoing ICSI-PGT at the authors' centre from March 2017 to March 2021. SDF was assessed using the sperm chromatin structure assay. The population was divided into low and high SDF groups according to cut-off values found by the receiver operating characteristic (ROC) curve. A 1:1 ratio propensity score matching (PSM) method was used to control for potential confounding factors, and a generalized linear mixed model was established to evaluate the relationship between SDF and the embryonic aneuploidy rate.

RESULTS

The ROC curve indicated a threshold of 30%. In total, 132 couples were included after PSM, and the high SDF group (>30%) had significantly higher SDF (40.74% ± 9.78% versus 15.54% ± 7.86%, P < 0.001) and a higher embryo aneuploidy rate (69.36% versus 53.96%, P < 0.001) compared with the low SDF group (≤30%). The two pronuclear fertilization rate, cleavage rate, rate of high-quality embryos at day 3 rate, blastocyst rate, biochemical pregnancy rate, clinical pregnancy rate, miscarriage rate, live birth rate, caesarean section rate, preterm birth rate, singleton rate and low birthweight rate were similar in both groups (P > 0.05). After PSM, SDF > 30% was significantly correlated with an increased embryo aneuploidy rate after adjusting for all confounding variables (adjusted odds ratio 1.70, 95% CI 1.00-2.88, P = 0.049).

CONCLUSIONS

SDF > 30% was associated with an increased embryo aneuploidy rate in couples with normal karyotypes undergoing PGT, but did not affect embryonic and clinical outcomes after transfer of euploid embryos.

[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.

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.