Effect of sperm DNA fragmentation on embryo euploidy rate in assisted reproductive technologies: a systematic review and meta-analysis

Abstract

Objectives

To quantitatively evaluate the association between sperm DNA fragmentation (SDF) and embryo euploidy rates in assisted reproductive technology (ART) cycles through a systematic review and meta-analysis.

Materials and methods

Following the PRISMA 2020 guidelines, a comprehensive search of PubMed, Web of Science, Embase, Scopus, and the Cochrane Library was conducted from inception to August 5, 2025. Eligible studies included infertile couples undergoing in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI), in which SDF was assessed using validated assays and embryo euploidy was determined via preimplantation genetic testing for aneuploidy (PGT-A). The Newcastle–Ottawa Scale was used for quality assessment. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using random- or fixed-effects models based on heterogeneity.

Results

Six studies involving 1,516 ART cycles met the inclusion criteria. All studies measured SDF using the sperm chromatin structure assay (SCSA), with cutoff values ranging from 15 to 30%. Embryo chromosomal status was evaluated at the blastocyst stage using PGT-A platforms, such as next-generation sequencing (NGS), array comparative genomic hybridization (aCGH), or single nucleotide polymorphism (SNP) arrays, with whole genome amplification (WGA) applied as a pre-analytical step rather than a detection method. Meta-analysis revealed no significant association between high SDF and embryo euploidy when using the 15% cutoff (pooled OR = 0.897; 95% CI 0.741–1.085; I² = 0.0%). At the 30% cutoff, high SDF (DFI ≥ 30%) was associated with lower embryo euploidy rates (pooled OR = 0.742; 95% CI 0.558–0.988; I² = 62.2%).

Conclusions

Elevated SDF, particularly above 30%, is associated with a reduced likelihood of obtaining euploid embryos in ART cycles, suggesting a potential threshold-dependent effect of sperm DNA integrity on embryo chromosomal normality. These findings support the integration of SDF assessment into the evaluation of selected couples, especially in cases of recurrent ART failure or advanced maternal age. Further prospective studies with standardized SDF protocols and uniform PGT-A methods are warranted to validate these results.

Introduction

Embryo euploidy, defined as the presence of a normal chromosomal complement, is a critical determinant of embryo viability in assisted reproductive technology (ART) cycles, including in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) [1–3]. Euploid embryos, when transferred, have a higher likelihood of successful implantation, reduced miscarriage risk, and improved live birth outcomes compared with aneuploid embryos [3–5]. Preimplantation genetic testing for aneuploidy (PGT-A) has become an essential tool to assess chromosomal status, enabling clinicians to identify euploid embryos for transfer and thereby optimize ART success rates. As such, factors influencing embryo euploidy are of great clinical and research interest [6].

Traditionally, embryo chromosomal abnormalities have been primarily attributed to maternal factors, particularly advanced maternal age, which is strongly associated with meiotic errors in oocytes [7]. However, emerging evidence indicates that paternal contributions—especially sperm chromatin integrity—may also play a role in determining embryo chromosomal normality [8]. Among various markers of sperm quality, sperm DNA fragmentation (SDF) has gained increasing attention [9]. SDF represents the presence of single-or double-strand breaks in sperm nuclear DNA, arising from defective spermatogenesis, oxidative stress, apoptosis, or environmental insults [10]. Elevated SDF has been reported in conditions, such as varicocele, infection, lifestyle-related exposures, and idiopathic male infertility [10, 11].

SDF reflects the integrity of paternal genetic material and is increasingly recognized as an important marker of male fertility [12, 13]. Numerous studies have investigated the impact of SDF on reproductive outcomes, with associations reported between high SDF and lower fertilization rates, impaired embryo development, poorer blastocyst quality, increased miscarriage risk, and reduced live birth rates [10, 14]. These findings have led to the incorporation of SDF testing into certain clinical decision-making processes, including recommendations for lifestyle modification, antioxidant therapy, or consideration of testicular sperm retrieval in select patients [10, 15]. However, the impact of SDF on embryo euploidy rate remains controversial. Some studies suggest that high SDF correlates with reduced euploidy rates [16–19], while others report no significant association [20–22]. Clarifying this relationship is essential to understanding male factor contributions to embryo chromosomal competence and may guide clinical decision-making in infertility treatment.

To our knowledge, this is the first meta-analysis to specifically and comprehensively examine the relationship between SDF and embryo euploidy rates in ART cycles, despite the increasing clinical use of PGT-A. This systematic review and meta-analysis are designed to fill this important gap by integrating all available evidence on the association between SDF and embryo euploidy. We aim to determine whether elevated SDF is linked to a reduced likelihood of obtaining euploid embryos. By delivering a robust quantitative synthesis, this study seeks to clarify the contribution of paternal DNA integrity to embryo chromosomal normality and provide insights that may inform clinical decision-making.

Materials and methods

Protocol and registration

This study was designed and conducted in strict accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement, ensuring methodological transparency and reproducibility. The protocol was prospectively registered in the International Prospective Register of Systematic Reviews (PROSPERO) prior to data extraction and analysis (Registration ID: CRD420251118851).

Literature search

A comprehensive search of PubMed, Embase, Web of Science, Cochrane Library, and Scopus was performed from inception to 5 August 2025. The search strategy combined free-text keywords and Medical Subject Headings (MeSH) related to sperm DNA fragmentation and embryo chromosomal status, including terms, such as “sperm DNA fragmentation,” “DNA fragmentation index,” “embryo euploidy,” “euploidy,” “embryo aneuploidy,” “aneuploidy,” “PGT-A,” “chromosomal normality,” “in vitro fertilization,” and “intracytoplasmic sperm injection.” In addition, the reference lists of included studies and relevant reviews were manually screened to identify additional eligible publications.

Inclusion and exclusion criteria

Two independent investigators (BW and YF) screened the titles, abstracts, and full texts of all identified records, and any discrepancies were resolved by consensus or consultation with a third reviewer. Studies were included if they met the following criteria: human studies involving infertile couples undergoing assisted reproductive technology (IVF or ICSI); SDF measured using validated assays, such as terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), sperm chromatin structure assay (SCSA), single cell gel electrophoresis (Comet assay), or sperm chromatin dispersion test (SCD); embryo euploidy rate assessed by PGT-A using next-generation sequencing (NGS), array comparative genomic hybridization (aCGH), or single nucleotide polymorphism (SNP) arrays; whole genome amplification (WGA) was applied as a pre-analytical step when required; and sufficient data available to calculate odds ratios (ORs) or directly extract embryo euploidy outcomes. Exclusion criteria were animal studies, reviews, editorials, conference abstracts without full data, or case reports; studies not reporting embryo euploidy outcomes or lacking data for meta-analysis; and non-English publications unless detailed data extraction was feasible.

Data extraction and quality assessment

Data extraction was independently performed by two investigators (BW and YF) using a standardized form, and discrepancies were resolved by discussion. To ensure data integrity and consistency, all extracted data and quality assessments were cross-verified by the review team. Any discrepancies or inconsistencies identified during the integrity check were re-evaluated against the original publications before final inclusion. The methodological quality of observational studies was independently assessed in duplicate by two reviewers (BW and YF) using the Newcastle–Ottawa Scale (NOS), which assigns scores ranging from 0 to 9 and classifies studies as low (0–4), moderate (5–6), or high quality (7–9). Any disagreement in quality scoring was resolved through consensus or consultation with a third reviewer (ZZ).

Statistical analyses

Meta-analyses were performed in R (version 4.4.2) using the ‘meta’ package. The primary outcome was embryo euploidy rate (euploid embryos per total embryos analyzed). Effect sizes were expressed as ORs with 95% confidence intervals (CIs). When multiple studies reported relevant outcomes, pooled ORs were calculated.

Statistical heterogeneity was assessed using Cochran’s Q test and quantified with the I² statistic, with I² values > 50% indicating substantial heterogeneity. When substantial heterogeneity was present (I² > 50%), a random-effects model (DerSimonian–Laird method) was used to calculate the OR. In the absence of significant heterogeneity (I² ≤ 50%), a fixed-effects model was applied to compute the pooled OR. Two-sided p < 0.05 was considered statistically significant.

Results

Study selection

A total of 1356 studies were identified through database searches (PubMed: n = 689; Web of Science: n = 268; Embase: n = 201; Scopus: n = 109; Cochrane Library: n = 89) and 0 through manual searching. After removing duplicates (n = 787), 569 studies were screened, of which 17 were assessed for full-text eligibility. Ultimately, 6 studies met the inclusion criteria and were included in the final analysis [16, 19, 20, 23–25] (Fig. 1).

Fig. 1.

Flow diagram outlining the study selection process. A total of 1356 records were identified through database searches (PubMed, Web of Science, Embase, Scopus, and Cochrane Library). After removing duplicates, 569 records remained for screening. Following title and abstract screening, 552 records were excluded due to being reviews, letters, non-English publications, or not meeting the inclusion criteria. Seventeen full-text articles were assessed for eligibility, of which 11 were excluded due to missing embryo ploidy data or insufficient information for meta-analysis. Ultimately, 6 studies were included in the quantitative synthesis

Study characteristics

A total of six studies, published between 2017 and 2025, were included in this systematic review and meta-analysis, comprising a total of 1516 ART cycles. Both IVF and ICSI were utilized as ART methods. In all studies, embryo chromosomal status was evaluated at the blastocyst stage, providing consistency in developmental assessment.

SDF was measured by SCSA in all included studies. High and low SDF groups were defined based on cutoff values ranging from 15 to 30%, although specific thresholds varied slightly among studies. Embryo chromosomal status was determined using next-generation sequencing (NGS), array comparative genomic hybridization (aCGH), or single nucleotide polymorphism (SNP) array platforms, with whole genome amplification (WGA) applied as a pre-analytical step rather than a chromosomal detection method. These molecular techniques enabled reliable detection of chromosomal abnormalities, although methodological heterogeneity in the type of PGT-A platform used may have introduced variability across studies.

The methodological quality of the included studies was assessed using the NOS, with scores ranging from 6 to 9, indicating an overall moderate to high quality of evidence. Detailed characteristics of the included studies are provided in Table 1.

Table 1.

Characteristics of included studies evaluating the association between sperm DNA fragmentation and embryo euploidy rate in ART cycles

First author	Year	Country	Study design	SDF group definition	Euploidy rate, % (n)	SDF assay	ART type	Male age (years)	DFI (%)	Number of couples	Cycles (n)	Euploidy assessment method	Embryo stage	NOS score
Gao et al	2023	China	Retrospective cohort study	Low DFI (DFI < 27%), high DFI (DFI ≥ 27%)	low DFI: 70.39% (435/618), high DFI: 63.64% (77/121)	SCSA	IVF with PGT-A	low DFI: 32.20 ± 0.25, high DFI: 34.82 ± 0.76	NR	174	238	NGS	Blastocyst	6
Kong et al	2025	China	Retrospective cohort study	Low DFI (DFI < 15%), moderate DFI (15% ≤  DFI ≤ 30%), high DFI (DFI > 30%)	low DFI: 31.3% (126/403), moderate DFI: 28.5% (55/193), high DFI: 28.2% (20/71)	SCSA	ICSI with PGT-A	low DFI: 40.6 ± 4.6, moderate DFI: 43.4 ± 5.5, high DFI: 44.5 ± 4.9	low DFI: 8.6 ± 3.5, moderate DFI: 20.9 ± 3.9, high DFI: 39.9 ± 8.4	492	492	NGS (with WGA)	Blastocyst	9
Ping et al	2023	China	Retrospective cohort study	Low DFI (DFI ≤ 15%), moderate DFI (15% < DFI < 30%), high DFI (DFI ≥ 30%)	low DFI: 72.2% (148/205),moderate DFI: 71.6% (111/155), high DFI: 57.3% (55/96)	SCSA	ICSI with PGT-A	low DFI: 33.74 ± 3.96, moderate DFI: 33.34 ± 3.91, high DFI: 35.44 ± 4.56	low DFI: 11.74 ± 2.74, moderate DFI: 20.52 ± 3.53, high DFI: 43.51 ± 9.63	119	119	NGS	Blastocyst	6
Yang et al	2023	China	Retrospective cohort study	Normal DFI (DFI < 15%), high DFI (DFI ≥ 15%)	normal DFI: 62.2% (102/164), high DFI: 55.3% (52/94)	SCSA	ICSI with PGT-A	normal DFI: 30.7 ± 5.6, high DFI: 33.5 ± 4.4	normal DFI: 8.5 ± 4.4, high DFI: 28.5 ± 10.7	64	64	NGS (with WGA)	Blastocyst	6
Fu et al	2023	China	Retrospective cohort study	Low DFI (DFI ≤ 30%), high DFI (DFI > 30%)	low DFI: 41.3% (816/1974), high DFI: 29.7% (129/434)	SCSA	ICSI with PGT-A	low DFI: 33.85 ± 5.38, high DFI: 32.18 ± 4.40	low DFI: 13.98 ± 6.77, high DFI: 41.39 ± 9.98	426	426	SNP array	Blastocyst	6
Gat et al	2017	Canada	Retrospective cohort	Low DFI (DFI ≤ 15%), moderate DFI (15% < DFI < 30%), high DFI (DFI ≥ 30%)	low DFI: 46.0% (119/259), moderate DFI: 47.4% (83/175), high DFI: 50.8% (59/116)	SCSA	IVF/ICSI with PGT-A	low DFI: 38.3 (range 29–62), moderate DFI: 45.6 (range 31–61), high DFI: 45.1 (range 32–62)	low DFI: 10.2 ± 3, moderate DFI: 20.7 ± 4.5, high DFI: 43.12 ± 13.8	134	177	aCGH	Blastocyst	7

ART assisted reproductive technology, DFI DNA fragmentation index, SDF sperm DNA fragmentation, SCSA sperm chromatin structure assay, NGS next generation sequencing, WGA whole genome amplification, SNP array single nucleotide polymorphism array, aCGH array comparative genomic hybridization, NR not reported

Main findings

Analyses were conducted using multiple sperm DNA fragmentation index (DFI) cutoff values to assess their association with embryo euploidy rates (Figs. 2, 3). In the comparison based on the 15% threshold, no statistically significant difference was observed between the low (DFI ≤ 15%) and high (DFI > 15%) groups (pooled OR = 0.897; 95% CI 0.741–1.085; I² = 0.0%). Similarly, when comparing DFI ≤ 15% with the intermediate range (15% < DFI < 30%), no significant difference was detected (pooled OR = 1.037; 95% CI 0.822–1.308; I² = 0.0%). Comparisons between the low and very high DFI groups (DFI ≤ 15% vs. DFI ≥ 30%) and between intermediate and very high DFI groups (15% < DFI < 30% vs. DFI ≥ 30%) also revealed no statistically significant differences, although moderate-to-high heterogeneity was noted (pooled OR = 1.213; 95% CI 0.733–2.006; I² = 68.2% and pooled OR = 1.179; 95% CI 0.735–1.891; I² = 57.9%, respectively). Although no statistically significant difference was observed between the DFI ≤ 15% and DFI ≥ 30% groups (pooled OR = 1.213; 95% CI 0.733–2.006), the wide confidence interval indicates imprecision, most likely due to the relatively small number of participants in the high-DFI subgroup, which may have limited statistical power. In contrast, when applying a 30% cutoff, a statistically significant difference emerged, with higher embryo euploidy rates observed in the DFI < 30% group compared to the DFI ≥ 30% group (pooled OR = 1.348; 95% CI 1.013–1.793; I² = 62.2%). These findings suggest that elevated SDF, particularly above the 30% threshold, may be associated with a reduced likelihood of obtaining euploid embryos, whereas associations are not evident at lower cutoff thresholds.

Fig. 2.

Forest plots (A–C) comparing embryo euploidy rates across different sperm DNA fragmentation index (DFI) thresholds: (A) DFI ≤ 15% vs. DFI > 15%, (B) DFI ≤ 15% vs. 15% < DFI < 30%, and (C) DFI ≤ 15% vs. DFI ≥ 30%. Pooled odds ratios (OR) and 95% confidence intervals (CI) were calculated using a fixed-effects model when I² ≤ 50% and a random-effects model when I² > 50%. Squares indicate study-specific estimates (size proportional to weight), horizontal lines represent 95% CI, and diamonds show pooled estimates

Fig. 3.

Forest plots (A, B) comparing embryo euploidy rates across different sperm DNA fragmentation index (DFI) thresholds: (A) 15% < DFI < 30% vs. DFI ≥ 30% and (B) DFI < 30% vs. DFI ≥ 30%. Pooled odds ratios (OR) and 95% confidence intervals (CI) were calculated using a fixed-effects model when I² ≤ 50% and a random-effects model when I² > 50%. Squares indicate study-specific estimates (size proportional to weight), horizontal lines represent 95% CI, and diamonds show pooled estimates

Discussion

This systematic review and meta-analysis provides the first comprehensive quantitative synthesis of the relationship between SDF and embryo euploidy rates in ART cycles. Across six eligible studies involving 1,516 ART cycles, we found that elevated SDF was significantly associated with a reduced likelihood of obtaining euploid embryos when a higher threshold (DFI ≥ 30%) was applied, whereas no significant association was observed at lower cutoffs (DFI > 15%). The heterogeneity was moderate for the 30% cutoff and minimal for the 15% cutoff, suggesting that the threshold effect is consistent across included studies. These findings indicate that the detrimental influence of SDF on embryo chromosomal normality becomes more pronounced beyond a certain level of DNA damage [16, 18, 23, 26]. For the comparison between DFI ≤ 15% and DFI ≥ 30%, although no statistical significance was observed, the wide confidence interval (0.733–2.006) should be interpreted as a reflection of imprecision due to the relatively small number of participants in the high-DFI subgroup. This limitation may have reduced the statistical power to detect potential differences rather than indicating the absence of a biological association.

Our results align with recent evidence showing that high SDF may compromise embryo chromosomal stability through mechanisms involving oxidative DNA damage, defective chromatin packaging, and impaired paternal genome repair capacity [16, 27, 28]. The inability of mature spermatozoa to repair DNA lesions means that the oocyte must compensate; however, oocyte repair capacity is finite and declines with maternal age [26, 28–30]. This is consistent with the findings of Fu et al. who reported that elevated SDF was significantly correlated with an increased chromosomal aneuploidy rate in miscarried conceptuses from women of advanced maternal age undergoing fresh embryo transfer, with an optimal SDF threshold as low as 8.5% [23]. Such results highlight the potential synergistic effect between paternal DNA damage and diminished oocyte repair capacity, and may partly explain the age-dependent susceptibility observed in some studies. Importantly, female age did not significantly differ between the high and low SDF groups in any of the included studies, minimizing the risk of age-related confounding in the pooled analysis.

Conversely, some studies, such as Broussard et al. did not find a significant relationship between SDF and embryo ploidy status, even when applying multiple cutoff values (15%, 20%, and 30%) [21]. Discrepancies between studies may be attributable to differences in SDF assay type and timing (e.g., assessment on neat vs. processed samples) [31], variation in PGT-A platforms (NGS vs. aCGH or FISH [fluorescence in situ hybridization]) [32, 33], and study population characteristics, including maternal age and infertility etiology. Notably, earlier studies using less sensitive PGT-A methods may have underestimated subtle chromosomal abnormalities, such as segmental aneuploidies or mosaicism, potentially obscuring true associations [32, 34, 35]. Importantly, none of the included studies used FISH for PGT-A; all applied modern platforms, such as NGS, aCGH, or SNP arrays, which offer improved resolution and the ability to detect whole-chromosome aneuploidies, most segmental abnormalities above the detection threshold, and a proportion of mosaic cases.

From a mechanistic perspective, high SDF could influence embryo chromosomal status through two primary pathways: (1) paternal meiotic errors leading to sperm chromosomal copy number abnormalities [16, 29], although current PGT-A platforms—NGS, aCGH, and SNP arrays—typically achieve a resolution of approximately 5–10 Mb and cannot detect small deletions or single nucleotide variants [32, 35] and (2) early embryonic mitotic errors, where oxidative stress-induced DNA breaks may disrupt paternal centrosome function, spindle assembly, and chromosome segregation, increasing mosaicism and whole chromosome aneuploidy risk. Experimental studies support this model, demonstrating delayed cell cycle progression and genomic instability in embryos derived from sperm with high DNA damage.

The limited number of studies (n = 6) and overall sample size (1516 cycles), particularly in the high SDF group, may have reduced the statistical power of the pooled analysis and partly explain the moderate heterogeneity observed at the 30% cutoff (I² = 62.2%). Although a random-effects model was used to account for between-study variability, residual heterogeneity may remain. Potential sources include differences in PGT-A platforms (NGS, aCGH, and SNP arrays), maternal age distribution, and ART type (IVF vs. ICSI). Future studies should perform subgroup analyses or meta-regression to more precisely identify these contributors.

Another limitation is that all included studies measured SDF using SCSA. Although SCSA is reproducible and clinically validated, it primarily reflects susceptibility to DNA denaturation and may not capture all types of sperm DNA damage. Other assays, such as TUNEL and Comet, detect DNA strand breaks directly and could yield complementary information. Future studies incorporating multiple SDF detection methods would help determine which assay best predicts embryo chromosomal outcomes.

Finally, all included studies were conducted in China, which may limit the generalizability of our findings to populations with different genetic backgrounds, lifestyles, and clinical practice patterns. Inclusion of multicenter data from diverse geographic regions will be essential to validate these results and improve external validity.

From a clinical perspective, these findings underscore the importance of considering SDF assessment in couples with recurrent ART failure, recurrent pregnancy loss, or unexplained infertility, particularly when the female partner is of advanced maternal age [13, 14, 26, 36]. While ICSI can bypass certain fertilization barriers associated with sperm DNA fragmentation—such as impaired sperm chromatin decondensation and reduced sperm–oocyte fusion rates—it does not repair DNA strand breaks and, therefore, cannot prevent downstream chromosomal abnormalities or reduce the risk of embryo aneuploidy. In such cases, targeted interventions—including antioxidant therapy, varicocele repair, lifestyle optimization, or use of testicular sperm—have been proposed to lower SDF levels [11, 37–39]. However, robust evidence from randomized controlled trials is still lacking, and the clinical efficacy of these interventions in improving euploidy rates remains to be confirmed.

In summary, our meta-analysis suggests that elevated sperm DNA fragmentation, particularly above 30%, is associated with a lower probability of obtaining euploid embryos in ART. The results support a biologically plausible link between paternal genome integrity and embryo chromosomal competence, with a likely threshold effect beyond which oocyte repair mechanisms are insufficient to prevent chromosomal errors. Given the observed heterogeneity across studies, future research should prioritize prospective, multicenter trials using standardized SDF testing protocols, consistent PGT-A methodologies, and clearly defined cutoff values. Such efforts will be essential to clarify causality, refine clinical thresholds, and determine whether interventions that lower SDF can reliably improve chromosomal outcomes and overall ART success rates.

Author contributions

Bangbei Wan and Weiying Lu designed the study and analyzed the data; Bangbei Wan, Ning Ma, and Zhi Zhou revised the images; Bangbei Wan and Yu Fu, performed the literature search and collected data for the manuscript; Bangbei Wan and Weiying Lu revised the manuscript. All authors read and approved the final manuscript.

Funding

The Specific Research Fund of The Innovation Platform for Academicians of Hainan Province,YSPTZX202311,YSPTZX202311,the Key R&D Projects of Hainan Province, ZDYF2022SHFZ074, ZDYF2022SHFZ280, ZDYF2017086, and ZDYF2019157, ZDYF2022SHFZ074, ZDYF2022SHFZ280, ZDYF2017086, and ZDYF2019157, the Natural Science Foundation of Hainan Province, 820RC771, the National Natural Science Foundation of China, 82160544 and 82260304

Data availability

No datasets were generated or analysed during the current study.

Declarations

Ethics approval and consent to participate

Not applicable.

Competing interests

The authors declare no competing interests.