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Cited by 23Sperm and Testicular FunctionMale Reproductive Health StudiesReproductive Health and Technologies

Isolated teratozoospermia: revisiting its relevance in male infertility: a narrative review

Open access
Atmoko, Widi, Savira, Missy, Shah, Rupin, Chung, Eric, Agarwal, Ashok·2024·Translational Andrology and Urology
DOI 10.21037/tau-23-397PMC PMC10932644
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Abstract

Background and Objective: Basic semen analysis is the first step in the evaluation of male infertility. It includes an assessment of sperm morphology which is believed to reflect on overall spermatogenesis and sperm function. Teratozoospermia, defined as abnormal sperm morphology, is frequently present in association with severe oligoasthenozoospermia, but isolated teratozoospermia (in the presence of normal counts and motility) is a poorly understood clinical entity with conflicting implications in terms of fertility potential and treatment strategies. The following paper aims to: (I) discuss the classification of sperm morphology, causes, and molecular mechanism of teratozoospermia; (II) analyze the clinical significance and potential treatment options of isolated teratozoospermia as a cause of male infertility and a predictor of fertility outcome; and (III) provide a SWOT (strengths, weaknesses, opportunities, and threats) analysis based on the existing literature on this topic. Methods: A comprehensive search from database inception to 25 April 2023 was conducted in PubMed for relevant papers relating to isolated teratozoospermia in male infertility. Finally, seven systematic reviews/reviews/meta-analyses and 81 original articles were synthesized into the current narrative review. Key Content and Findings: Classification of sperm morphology has evolved significantly since the first edition of the World Health Organization (WHO) Manual of Human Semen Analysis. Kruger's strict criteria are the most used classification and have been shown to correlate with fertility outcomes. There are many causes of teratozoospermia including genetic and environmental factors and physical conditions like varicocele. Teratozoospermia correlates with sperm DNA damage, elevated oxidative stress, low antioxidant function, and apoptotic alterations, which can result in impaired spermatozoa function and lower pregnancy rates. However, the clinical correlation between teratozoospermia and assisted reproductive technology (ART) outcome shows conflicting data with recent meta-analyses suggesting that isolated teratozoospermia was not associated with poor fertility outcomes from ART and that intrauterine insemination (IUI) can be an effective option even in the presence of teratozoospermia. There is very limited data on effective therapeutic options to treat idiopathic isolated teratozoospermia. The opportunity for future research is huge to fill the gap in the medical literature on this topic. Conclusions: Contemporary literature on isolated teratozoospermia shows conflicting results in terms of its actual clinical implication in male infertility and the utility of available treatment options. Further research is warranted on this clinical entity to improve sperm function and future paternity.

AI snapshot

Written from the paper’s full text.

TL;DR

This narrative review synthesizes evidence on isolated teratozoospermia in male infertility, covering classification, causes, molecular mechanisms, clinical significance, and management. It concludes that the clinical relevance and optimal treatment of isolated teratozoospermia remain controversial, with conflicting data on natural and assisted reproduction outcomes and no clear treatment recommendations.

Key findings

  • Isolated teratozoospermia prevalence was higher in fertile controls than infertile men in one cited study: 35.9% in 103 fertile controls versus 11.9% in 1,824 infertile men.
  • Assisted reproduction outcomes are conflicting: one meta-analysis found no significant decrease in pregnancy likelihood after IVF with or without ICSI in couples with isolated teratozoospermia, while another study reported lower cumulative live birth after four IUI attempts in teratozoospermia groups (30.32% vs. 53.22%, P<0.001).
  • In men with isolated teratozoospermia and clinically palpable varicocele, varicocelectomy was associated with a 30.5% natural pregnancy rate versus 16.7% in an antioxidant-only control group; antioxidants improved sperm morphology (0.9% vs. 1.5%, P=0.04) and sperm DNA fragmentation (33% vs. 29%, P=0.03) after 6 months in one study.
  • Genetic causes are identified mainly for monomorphic defects such as macrozoospermia (e.g., AURKC mutations) and globozoospermia (e.g., DPY19L2 variants in more than 55% of Chinese globozoospermic men in one multicenter study), but the etiology of most cases remains unclear.

Methods

  • Narrative review based on a PubMed search from database inception to 25 April 2023, using terms related to teratozoospermia, isolated abnormal sperm morphology, male infertility, and related concepts.
  • From 145 articles reviewed, 88 publications were included: seven systematic reviews/reviews/meta-analyses and 81 original articles; 55 were published in the last ten years.
  • Evidence was extracted and synthesized narratively, with a SWOT analysis of the current evidence on isolated teratozoospermia.

Limitations

  • Stated by the paper: available evidence is conflicting and of low quality; there are no guidelines for treating isolated teratozoospermia; there are no controlled trials of antioxidants in men with isolated teratozoospermia without varicocele; and many genetic findings come from case reports or case series.
  • Evident from the text: as a narrative review, it did not use a registered protocol, formal risk-of-bias assessment, or quantitative meta-analysis, and the search was limited to PubMed and English-language articles.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.21037/tau-23-397

Cites

97 of 97 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

87 of 157 cited sources checked · 57 supported · 0 flagged · accuracy not yet measured

  • Findingcitation

    A multicenter study by Pacey et al. in 2014 showed a non-significant association between smoking, alcohol consumption, type of underwear, and body mass index to sperm morphology.

    “On the contrary, a multicenter study by Pacey et al. in 2014 showed a non-significant association between smoking, alcohol consumption, type of underwear, and even body mass index to sperm morphology.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [58] Pacey AA Povey AC Clyma JA Modifiable and non-modifiable risk factors for poor sperm morphology. Hum Reprod 2014; 29: 1629- 36. 10.1093/humrep/deu116 24899128 source
  • Interpretationreasoning

    The low cut-off points may have missed a proper infertility evaluation.

    “Therefore, the low cut-off points may have missed a proper infertility evaluation (32).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [32] Jensen CFS Khan O Nagras ZG Male infertility problems of patients with strict sperm morphology between 5-14% may be missed with the current WHO guidelines. Scand J Urol 2018; 52: 427- 31. 10.1080/21681805.2018.1548503 30602328 source
  • Interpretationcitation

    There is still the possibility of other contributing male infertility factors in patients with 5-14% normal sperm morphology.

    “Moreover, there is still the possibility of other contributing male infertility factors in patients with 5–14% normal sperm morphology.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [32] Jensen CFS Khan O Nagras ZG Male infertility problems of patients with strict sperm morphology between 5-14% may be missed with the current WHO guidelines. Scand J Urol 2018; 52: 427- 31. 10.1080/21681805.2018.1548503 30602328 source
  • Findingcitation

    In some cases of globozoospermia with certain genetic mutations, sperm cannot initiate oocyte activation even after the use of ICSI.

    “In some cases of globozoospermia with certain genetic mutations, sperm cannot initiate oocyte activation even after the use of ICSI (45).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [45] Huang G Zhang X Yao G A loss-of-function variant in SSFA2 causes male infertility with globozoospermia and failed oocyte activation. Reprod Biol Endocrinol 2022; 20: 103. 10.1186/s12958-022-00976-5 35836265 PMC9281110 source
  • Findingcitation

    Some studies have shown a correlation between sperm morphological defects and nuclear genetic defects, apoptotic alterations, and reactive oxidative stress, which may negatively impact fertility potential.

    “Some studies have shown a correlation between sperm morphological defects and nuclear genetic defects, apoptotic alterations, and reactive oxidative stress, which may negatively impact fertility potential (13-15).”
    Quote in the paperSubstantial claim2 of 3 sources checked
    • cites [13] Oumaima A Tesnim A Zohra H Investigation on the origin of sperm morphological defects: oxidative attacks, chromatin immaturity, and DNA fragmentation. Environ Sci Pollut Res Int 2018; 25: 13775- 86. 10.1007/s11356-018-1417-4 29508198 source
    • cites [14] Ammar O Mehdi M Muratori M. Teratozoospermia: Its association with sperm DNA defects, apoptotic alterations, and oxidative stress. Andrology 2020; 8: 1095- 106. 10.1111/andr.12778 32096605 source
    • cites [15] Agarwal A Tvrda E Sharma R. Relationship amongst teratozoospermia, seminal oxidative stress and male infertility. Reprod Biol Endocrinol 2014; 12: 45. 10.1186/1477-7827-12-45 24884815 PMC4049374 source

      The Background (page unavailable) links abnormal sperm morphology with DNA fragmentation and reactive oxygen species overproduction, and the Discussion relates abnormal morphology to reduced fertilization and pregnancy rates. Our copy does not establish a correlation between morphological defects and apoptotic alterations, so that part of the claim is unsupported. (LLM, conf=0.87)

      Experimental — accuracy not yet measured
  • May combine two claims. 36
  • Classified as probably not a substantial claim. 31

  • May combine two claims.

    Findingcitation

    Pacey et al. found that sample production in summer and Cannabis use in the 3 months before semen collection are associated with teratozoospermia in men aged thirty or less.

    “Instead, they found that sample production in summer and Cannabis use in the 3 months before semen collection are associated with teratozoospermia in men aged thirty or less (58).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [58] Pacey AA Povey AC Clyma JA Modifiable and non-modifiable risk factors for poor sperm morphology. Hum Reprod 2014; 29: 1629- 36. 10.1093/humrep/deu116 24899128 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingcitation

    Another study found that the presence of asymptomatic bacteriospermia does not correlate with abnormal semen parameters.

    “These findings were in contrast with another study that found that the presence of asymptomatic bacteriospermia does not correlate with abnormal semen parameters (65).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [65] Vilvanathan S Kandasamy B Jayachandran AL Bacteriospermia and Its Impact on Basic Semen Parameters among Infertile Men. Interdiscip Perspect Infect Dis 2016; 2016: 2614692. 10.1155/2016/2614692 26880908 PMC4736773 source

  • May combine two claims.

    Premisecitation

    The strict criteria consider a slight or borderline abnormality as abnormal, resulting in a significantly lower threshold of normally shaped sperm compared to the liberal approach.

    “These criteria consider a slight or borderline abnormality as abnormal, which results in a significantly lower threshold of normally shaped sperm compared to the liberal approach (30).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [30] Gatimel N Moreau J Parinaud J Sperm morphology: assessment, pathophysiology, clinical relevance, and state of the art in 2017. Andrology 2017; 5: 845- 62. 10.1111/andr.12389 28692759 source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Globozoospermia is the round-headed sperm without acrosome, with an aberrant nuclear membrane, and a defect on the midpiece of sperm.

    “The other abnormality is globozoospermia, the round-headed sperm without acrosome, with an aberrant nuclear membrane, and a defect on the midpiece of sperm (43).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [43] Ricci G Andolfi L Zabucchi G Ultrastructural Morphology of Sperm from Human Globozoospermia. Biomed Res Int 2015; 2015: 798754. 10.1155/2015/798754 26436098 PMC4578751 source

      The Results describe human globozoospermic sperm with round heads, no acrosomes, and an abnormal tail-coiling sequence involving the midpiece. The Discussion describes nuclear-envelope defects in animal models, but does not establish an aberrant nuclear membrane as a feature of the human sperm examined. (LLM, conf=0.85)

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S2 (checkable).

    Interpretationcitation

    There needs to be more evidence of the clinical value of multiple sperm defect indices.

    “There needs to be more evidence of their clinical value (30).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [30] Gatimel N Moreau J Parinaud J Sperm morphology: assessment, pathophysiology, clinical relevance, and state of the art in 2017. Andrology 2017; 5: 845- 62. 10.1111/andr.12389 28692759 source

  • May combine two claims.

    Findingcitation

    Febrile illness and testicular cancer have been shown to affect sperm morphology due to defective spermatogenesis.

    “Febrile illness and testicular cancer have also been shown to affect sperm morphology due to defective spermatogenesis (70,71).”
    Quote in the paperNot a substantial claim2 of 2 sources checked
    • cites [70] Carlsen E Andersson AM Petersen JH History of febrile illness and variation in semen quality. Hum Reprod 2003; 18: 2089- 92. 10.1093/humrep/deg412 14507826 source

      No passage from our indexed copy states that febrile illness affects sperm morphology through defective spermatogenesis. Searches for febrile illness, morphology, fever, and testicular cancer returned no substantive passage; the only result was bibliographic metadata and keywords, which cannot establish the claim. (LLM, conf=0.73)

      Experimental — accuracy not yet measured
    • cites [71] Ghasemi B Mosadegh Mehrjardi A Jones C Semen analysis of subfertility caused by testicular carcinoma. Int J Reprod Biomed 2020; 18: 539- 50. 10.18502/ijrm.v13i7.7371 32803118 PMC7385918 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingcitation

    Some abnormalities related to varicocele include elongated sperm head and abnormal retention of cytoplasmic droplets.

    “Some abnormalities that are related to varicocele include elongated sperm head and abnormal retention of cytoplasmic droplets (68,69).”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites [68] Vásquez F Soler C Camps P Spermiogram and sperm head morphometry assessed by multivariate cluster analysis results during adolescence (12-18 years) and the effect of varicocele. Asian J Androl 2016; 18: 824- 30. 10.4103/1008-682X.186873 27751986 PMC5109870 source

      The Results (Sperm head morphometric subpopulations; page unavailable) report more elongated sperm heads in subpopulations from adolescents with varicocele. The paper does not report abnormal retention of cytoplasmic droplets, so it supports only the sperm-head portion of the claim. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
    • cites [69] Zini A Defreitas G Freeman M Varicocele is associated with abnormal retention of cytoplasmic droplets by human spermatozoa. Fertil Steril 2000; 74: 461- 4. 10.1016/S0015-0282(00)00703-2 10973638 source

  • May combine two claims.

    Findingcitation

    Other genetic causes of sperm morphological abnormalities include mutations of SUN5, SPATA20, ACTL7A, and CCIN, which result in pinhead spermatozoa, acephalic spermatozoa syndrome, bubble-shaped acrosome, and severe head malformations, respectively.

    “Other genetic causes of sperm morphological abnormalities include mutations of the SUN5, SPATA20, ACTL7A, and CCIN genes which result in pinhead spermatozoa and acephalic spermatozoa syndrome, bubble-shaped acrosome and severe head malformations, respectively (37,48,49,50).”
    Quote in the paperNot a substantial claim1 of 4 sources checked
    • cites [37] Auger J. Assessing human sperm morphology: top models, underdogs or biometrics? Asian J Androl 2010; 12: 36- 46. 10.1038/aja.2009.8 20111080 PMC3739679 source

      Section 4 says several sperm abnormalities have a precise genetic origin, and the References list a study of acephalic spermatozoa described as a syndrome of genetic origin. But our copy does not identify SUN5, SPATA20, ACTL7A, or CCIN or link their mutations to the specific abnormalities claimed. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
    • cites [48] Wang X Jiang C Dai S Identification of nonfunctional SPATA20 causing acephalic spermatozoa syndrome in humans. Clin Genet 2023; 103: 310- 9. 10.1111/cge.14268 36415156 source
    • cites [49] Dai J Chen Y Li Q Pathogenic variant in ACTL7A causes severe teratozoospermia characterized by bubble-shaped acrosomes and male infertility. Mol Hum Reprod 2022; 28: gaac028. 10.1093/molehr/gaac028 35863052 source
    • cites [50] Fan Y Huang C Chen J Mutations in CCIN cause teratozoospermia and male infertility. Sci Bull (Beijing) 2022; 67: 2112- 23. 10.1016/j.scib.2022.09.026 36546111 source

  • Classified as probably not a substantial claim.

    Premisecitation

    ART, particularly ICSI, is often recommended in men with severe teratozoospermia.

    “Hence, assisted reproductive technology (ART), particularly intracytoplasmic sperm injection (ICSI), are often recommended in men with severe teratozoospermia (16,17).”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [16] Oehninger S Kruger TF Simon T A comparative analysis of embryo implantation potential in patients with severe teratozoospermia undergoing in-vitro fertilization with a high insemination concentration or intracytoplasmic sperm injection. Hum Reprod 1996; 11: 1086- 9. 10.1093/oxfordjournals.humrep.a019302 8671396 source
    • cites [17] El Khattabi L Dupont C Sermondade N Is intracytoplasmic morphologically selected sperm injection effective in patients with infertility related to teratozoospermia or repeated implantation failure? Fertil Steril 2013; 100: 62- 8. 10.1016/j.fertnstert.2013.02.048 23548938 source

      The Study Groups section reports that patients with severe teratozoospermia underwent ICSI or IMSI, supporting the use of these ART procedures in that group. But the Semen Evaluation and Preparation section lists other common indications for ICSI, and the paper does not say that ICSI is often recommended specifically for severe teratozoospermia. Its Discussion instead suggests IMSI may benefit those patients. (LLM, conf=0.83)

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Patients with Kartegener syndrome have immotile cilia syndrome due to abnormal morphology and function of the sperm tail.

    “Patients with Kartegener syndrome have immotile cilia syndrome, due to abnormal morphology and function of the sperm tail (66).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [66] Sha YW Ding L Li P. Management of primary ciliary dyskinesia/Kartagener’s syndrome in infertile male patients and current progress in defining the underlying genetic mechanism. Asian J Androl 2014; 16: 101- 6. 10.4103/1008-682X.122192 24369140 PMC3901865 source

      The Introduction identifies Kartagener’s syndrome as a form of primary ciliary dyskinesia involving abnormal ciliary function in several parts of the body. The Incidence and Clinical Manifestations section says abnormal sperm-flagellar structure may impair movement and cause male infertility; it does not say sperm-tail abnormalities cause the syndrome itself. Page numbers are unavailable in our copy. (LLM, conf=0.87)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Findingcitation

    The effect of sulfasalazine can be temporary and semen may return to normal after cessation of use.

    “The effect of the latter can be temporary and semen may return to normal after cessation of use (61).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [61] Toovey S Hudson E Hendry WF Sulphasalazine and male infertility: reversibility and possible mechanism. Gut 1981; 22: 445- 51. 10.1136/gut.22.6.445 6114897 PMC1419267 source

      The Conclusion reports that semen quality improves after sulphasalazine withdrawal, supporting the claim that the effect can be temporary. In the Results passage under HORMONE STUDIES, 11 of 14 patients had normal sperm density after at least two months off the drug, but mean motility remained below normal and morphology did not improve. The paper therefore supports recovery, not a general return of semen quality to normal. (LLM, conf=0.88)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Findingcitation

    The cut-off of 4% in the fifth edition was criticized as being too low, resulting in poor prediction of ART outcomes.

    “Although some research found a good correlation between the strict classification of sperm morphology and pregnancy outcome, the cut-off of 4% in the fifth edition was criticized as being too low, resulting in poor prediction of ART outcomes (31).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [31] Morbeck DE Leonard PH Weaver AL Sperm morphology: classification drift over time and clinical implications. Fertil Steril 2011; 96: 1350- 4. 10.1016/j.fertnstert.2011.08.036 21958691 source

      The Results and Discussion report that a 4% strict-morphology threshold did not predict pregnancy in the later IUI era. But the same threshold was predictive in the earlier era, and the paper attributes the loss of predictive value to classification drift, not to the fifth edition’s cut-off being too low. The study concerns IUI outcomes, rather than ART outcomes generally. (LLM, conf=0.87)

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingcitation

    One study found that isolated teratozoospermia was more common in fertile than infertile males.

    “and one study found that isolated teratozoospermia was more common in fertile than infertile males (20).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [20] Candela L Boeri L Capogrosso P Correlation among isolated teratozoospermia, sperm DNA fragmentation and markers of systemic inflammation in primary infertile men. PLoS One 2021; 16: e0251608. 10.1371/journal.pone.0251608 34097690 PMC8184012 source

  • May combine two claims.

    Findingcitation

    Morphological assessment can be highly subjective, with high intra- and inter-laboratory variations resulting in questionable reliability and high heterogeneity of the available evidence.

    “To further complicate matters, morphological assessment can be highly subjective, with high intra- and inter-laboratory variations resulting in questionable reliability and high heterogeneity of the available evidence (12).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [12] Agarwal A Sharma R Gupta S Sperm Morphology Assessment in the Era of Intracytoplasmic Sperm Injection: Reliable Results Require Focus on Standardization, Quality Control, and Training. World J Mens Health 2022; 40: 347- 60. 10.5534/wjmh.210054 34169687 PMC9253798 source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingcitation

    Two of the most commonly found monomorphic teratozoospermic defects are macrocephalic head syndrome (macrozoospermia) and total globozoospermia syndrome.

    “Interestingly, two of the most commonly found monomorphic teratozoospermic defects are macrocephalic head syndrome (macrozoospermia) and total globozoospermia syndrome (39).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [39] De Braekeleer M Nguyen MH Morel F Genetic aspects of monomorphic teratozoospermia: a review. J Assist Reprod Genet 2015; 32: 615- 23. 10.1007/s10815-015-0433-2 25711835 PMC4380889 source

  • May combine two claims.

    Premisecitation

    The Tygerberg strict criteria were based on the observation that the morphology of spermatozoa in the cervical mucus was better than those from the semen sample and similar to the morphology required for binding to zona pellucida.

    “This approach was based on the observation that the morphology of spermatozoa in the cervical mucus was better than those from the semen sample and similar to the morphology required for binding to zona pellucida (28,29).”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites [28] Menkveld R Franken DR Kruger TF Sperm selection capacity of the human zona pellucida. Mol Reprod Dev 1991; 30: 346- 52. 10.1002/mrd.1080300409 1751039 source
    • cites [29] Liu DY Baker HW. Morphology of spermatozoa bound to the zona pellucida of human oocytes that failed to fertilize in vitro. J Reprod Fertil 1992; 94: 71- 84. 10.1530/jrf.0.0940071 1552494 source

      The Introduction (page unavailable) says cervical mucus selects morphologically normal spermatozoa, and the study reports that normal spermatozoa bind to the zona pellucida at much higher rates than abnormal ones. Our copy does not establish that sperm morphology in cervical mucus is similar to the morphology needed for zona binding, or that this observation was the basis for the Tygerberg strict criteria. (LLM, conf=0.84)

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingcitation

    Isolated teratozoospermia contributed to 20% of all isolated sperm abnormality cases, accounting for more than 5% of infertile men cases based on a study of almost five thousand infertile men.

    “Isolated teratozoospermia contributed to 20% of all isolated sperm abnormality cases, accounting for more than 5% of infertile men cases based on a study of almost five thousand infertile men (83).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [83] Belloc S Benkhalifa M Cohen-Bacrie M Which isolated sperm abnormality is most related to sperm DNA damage in men presenting for infertility evaluation. J Assist Reprod Genet 2014; 31: 527- 32. 10.1007/s10815-014-0194-3 24566945 PMC4016368 source

  • Classified as probably not a substantial claim.

    Interpretationcitation

    Kovac et al. contended that sperm morphology assessment may not be a reliable indicator of fertility potential.

    “and hence they contended that sperm morphology assessment may not be a reliable indicator of fertility potential.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [82] Kovac JR Smith RP Cajipe M Men with a complete absence of normal sperm morphology exhibit high rates of success without assisted reproduction. Asian J Androl 2017; 19: 39- 42. 10.4103/1008-682X.189211 27751992 PMC5227671 source

  • May combine two claims.

    Findingcitation

    ROS production is higher among immature spermatozoa with abnormal morphology, which may indicate abnormal regulation of spermatogenesis.

    “Reactive oxygen species (ROS) production is also found to be higher among immature spermatozoa with abnormal morphology which may indicate abnormal regulation of spermatogenesis (76).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [76] Gil-Guzman E Ollero M Lopez MC Differential production of reactive oxygen species by subsets of human spermatozoa at different stages of maturation. Hum Reprod 2001; 16: 1922- 30. 10.1093/humrep/16.9.1922 11527899 source

  • Classified as probably not a substantial claim.

    Interpretationcitation

    Lockwood et al. suggested that IUI should be considered even in those with a very low percentage of sperm with normal shape.

    “and suggested that IUI should be considered even in those with a very low percentage of sperm with normal shape (88).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [88] Lockwood GM Deveneau NE Shridharani AN Isolated abnormal strict morphology is not a contraindication for intrauterine insemination. Andrology 2015; 3: 1088- 93. 10.1111/andr.12098 26384603 source

  • May combine two claims.

    Premisecitation

    IVF is sufficient and there is no need for ICSI just because of isolated teratozoospermia.

    “IVF is sufficient and there is no need for ICSI just because of isolated teratozoospermia (94).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [94] Keegan BR Barton S Sanchez X Isolated teratozoospermia does not affect in vitro fertilization outcome and is not an indication for intracytoplasmic sperm injection. Fertil Steril 2007; 88: 1583- 8. 10.1016/j.fertnstert.2007.01.057 17448467 source

  • May combine two claims.

    Findingcitation

    Abnormal sperm morphology in general has shown a correlation with changes in genetic materials, increased rate of apoptosis, overproduction of oxidative stress, and a decrease in antioxidant activities.

    “While some morphological defects are associated with specific functional deficiencies, such as those with tail defects that result in abnormal motility, abnormal sperm morphology, in general, has shown a correlation with changes in genetic materials, increased rate of apoptosis, overproduction of oxidative stress as well as a decrease in antioxidant activities (13-15).”
    Quote in the paperNot a substantial claim2 of 3 sources checked
    • cites [13] Oumaima A Tesnim A Zohra H Investigation on the origin of sperm morphological defects: oxidative attacks, chromatin immaturity, and DNA fragmentation. Environ Sci Pollut Res Int 2018; 25: 13775- 86. 10.1007/s11356-018-1417-4 29508198 source
    • cites [14] Ammar O Mehdi M Muratori M. Teratozoospermia: Its association with sperm DNA defects, apoptotic alterations, and oxidative stress. Andrology 2020; 8: 1095- 106. 10.1111/andr.12778 32096605 source
    • cites [15] Agarwal A Tvrda E Sharma R. Relationship amongst teratozoospermia, seminal oxidative stress and male infertility. Reprod Biol Endocrinol 2014; 12: 45. 10.1186/1477-7827-12-45 24884815 PMC4049374 source

      The Background (page not provided) links abnormal sperm morphology to DNA fragmentation and ROS overproduction. The copy does not establish a correlation with increased apoptosis or decreased antioxidant activity; the Conclusions instead propose further study of seminal antioxidant status. (LLM, conf=0.88)

      Experimental — accuracy not yet measured

  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationcitation

    Keegan et al. concluded that in men with isolated teratozoospermia IVF is sufficient and there is no need for ICSI just because of isolated teratozoospermia.

    “and concluded that in men with isolated teratozoospermia IVF is sufficient and there is no need for ICSI just because of isolated teratozoospermia (94).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [94] Keegan BR Barton S Sanchez X Isolated teratozoospermia does not affect in vitro fertilization outcome and is not an indication for intracytoplasmic sperm injection. Fertil Steril 2007; 88: 1583- 8. 10.1016/j.fertnstert.2007.01.057 17448467 source

  • May combine two claims.

    Findingcitation

    A recent study of 1,824 infertile men found that while 11.9% of infertile males had isolated teratozoospermia, the prevalence was higher in 103 fertile controls at 35.9%.

    “Interestingly, a recent study of 1,824 infertile men found that while 11.9% of infertile males had isolated teratozoospermia, the prevalence was higher in 103 fertile controls at 35.9% (20).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [20] Candela L Boeri L Capogrosso P Correlation among isolated teratozoospermia, sperm DNA fragmentation and markers of systemic inflammation in primary infertile men. PLoS One 2021; 16: e0251608. 10.1371/journal.pone.0251608 34097690 PMC8184012 source

  • May combine two claims.

    Findingcitation

    There is still an overlap between fertile and sub-fertile men, and multiple sperm defect indices cannot be used as a strict assessment to define men's sperm potential.

    “Even though these indices have been correlated to both in vivo and IVF outcomes, there is still an overlap between fertile and sub-fertile men, and they cannot be used as a strict assessment to define men’s sperm potential (5).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [5] World Health Organization. WHO Laboratory Manual for the Examination and Processing of Human Semen. 6th edition. Geneva: WHO Press, 2021.

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Findingnone given

    Macrozoospermia correlates with high sperm DNA fragmentation and results in primary infertility.

    “It also correlates with high sperm DNA fragmentation (SDF) and results in primary infertility.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingcitation

    Globozoospermia is associated with aneuploid spermatozoa and sperm DNA fragmentation.

    “Like macrozoospermia, it is also associated with aneuploid spermatozoa and SDF (44).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [44] Eskandari N Tavalaee M Zohrabi D Association between total globozoospermia and sperm chromatin defects. Andrologia 2018; 50:. 10.1111/and.12843 28660655 source

  • Probably not a substantial claim: may not pass S4 (based).

    Findingnone given

    There is very limited data on effective therapeutic options to treat idiopathic isolated teratozoospermia.

    “There is very limited data on effective therapeutic options to treat idiopathic isolated teratozoospermia.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    The included articles cover seven systematic reviews/reviews/meta-analyses and 81 original articles.

    “The included articles cover seven systematic reviews/reviews/meta-analyses and 81 original articles.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingown data

    A total of 88 publications were included in the review, of which 55 were published in the last ten years.

    “A total of 88 publications were included in this analysis, of which 55 of them were published in the last ten years.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingcitation

    One study found that patients with teratozoospermia had a higher proportion of spermatozoa with late-stage apoptosis, and there was a substantial correlation between the frequencies of atypical sperm forms and apoptotic biomarkers.

    “One study found that patients with teratozoospermia had a higher proportion of spermatozoa with late-stage apoptosis, and there was a substantial correlation between the frequencies of atypical sperm forms and apoptotic biomarkers (81).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [81] Ammar O Mehdi M Tekeya O Novel association between apoptotic sperm biomarkers with seminal biochemical parameters and acetylcholinesterase activity in patients with teratozoospermia. J Assist Reprod Genet 2019; 36: 2367- 78. 10.1007/s10815-019-01579-7 31512048 PMC6885487 source

  • May combine two claims.

    Findingcitation

    Kruger et al. reported that men with less than 4% sperm with normal morphology had a fertilization rate of 7.6% while those with normal morphology between 4% and 14% had a fertilization rate of 63.9%.

    “The predictive value of morphological assessment by strict criteria during IVF was first highlighted by Kruger et al. who reported that men with less than 4% sperm with normal morphology had a fertilization rate of 7.6% while those with normal morphology between 4% and 14% had a fertilization rate of 63.9% (90).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [90] Kruger TF Acosta AA Simmons KF Predictive value of abnormal sperm morphology in in vitro fertilization. Fertil Steril 1988; 49: 112- 7. 10.1016/S0015-0282(16)59660-5 3335257 source

  • May combine two claims.

    Findingcitation

    Oxidative stress results in lower protamination and disulfide bond formation, leading to DNA breaks and increased free radicals.

    “Oxidative stress results in lower protamination and disulfide bond formation, leading to DNA breaks and increased free radicals (13).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [13] Oumaima A Tesnim A Zohra H Investigation on the origin of sperm morphological defects: oxidative attacks, chromatin immaturity, and DNA fragmentation. Environ Sci Pollut Res Int 2018; 25: 13775- 86. 10.1007/s11356-018-1417-4 29508198 source

  • May combine two claims.

    Findingcitation

    Knez et al. found that the number of morphologically normal zygotes, blastocyst rate, and fraction of arrested embryos were better when using spermatozoa without head vacuoles than when using spermatozoa with vacuoles and other head problems.

    “This study also found that the number of morphologically normal zygotes, blastocyst rate, and fraction of arrested embryos were better when using spermatozoa without head vacuoles than when using spermatozoa with vacuoles and other head problems.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [92] Knez K Tomazevic T Zorn B Intracytoplasmic morphologically selected sperm injection improves development and quality of preimplantation embryos in teratozoospermia patients. Reprod Biomed Online 2012; 25: 168- 79. 10.1016/j.rbmo.2012.03.011 22717245 source

  • May combine two claims.

    Findingcitation

    Men with isolated teratozoospermia have higher rates of sperm DNA fragmentation, chromosomal aneuploidy, and chromosome 13 disomy.

    “Men with isolated teratozoospermia have higher rates of SDF, chromosomal aneuploidy, and chromosome 13 disomy.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [73] Tang SS Gao H Zhao Y Aneuploidy and DNA fragmentation in morphologically abnormal sperm. Int J Androl 2010; 33: e163- 79. 10.1111/j.1365-2605.2009.00982.x 19732195 source

  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationnone given

    Isolated teratozoospermia is a poorly understood clinical entity with conflicting implications for fertility potential and treatment strategies.

    “isolated teratozoospermia (in the presence of normal counts and motility) is a poorly understood clinical entity with conflicting implications in terms of fertility potential and treatment strategies.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Initial evaluation of male fertility potential involves medical and reproductive history, physical examination, and semen analysis.

    “Initial evaluation of the male fertility potential involves a medical and reproductive history, physical examination, and semen analysis (4).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [4] Salonia A, Bettochhi P, Capogrosso P, et al. EAU Guidelines on Sexual and Reproductive Health. Arnhem: EAU Guidelines: 2023 (last accessed 1 June 2023). Available online: http://uroweb.org/guidelines/compilations-of-all-guidelines/

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    Kruger's strict criteria have been shown to correlate with fertility outcomes.

    “Kruger’s strict criteria are the most used classification and have been shown to correlate with fertility outcomes.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    Kruger's strict criteria are the most used classification of sperm morphology.

    “Kruger’s strict criteria are the most used classification and have been shown to correlate with fertility outcomes.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    There are many causes of teratozoospermia, including genetic and environmental factors and physical conditions such as varicocele.

    “There are many causes of teratozoospermia including genetic and environmental factors and physical conditions like varicocele.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    Sperm DNA damage, elevated oxidative stress, low antioxidant function, and apoptotic alterations can result in impaired spermatozoa function and lower pregnancy rates.

    “Teratozoospermia correlates with sperm DNA damage, elevated oxidative stress, low antioxidant function, and apoptotic alterations, which can result in impaired spermatozoa function and lower pregnancy rates.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    The fourth and fifth editions of the WHO manual adopted 14% and 4% as the cut-off of normal sperm morphology, respectively.

    “The fourth [1999] and fifth [2010] editions of the WHO manual adopted 14% and 4% as the cut-off of normal sperm morphology, respectively (6,11).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [6] World Health Organization. WHO Laboratory Manual for the Examination and Processing of Human Semen. 5th edition. Geneva: WHO Press, 2010.

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [11] World Health Organization. WHO Laboratory manual for the examination of human semen and sperm-cervical mucus interaction. 4th edition. Cambridge: Cambridge University Press, 1999.

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    In macrozoospermia, the spermatozoa have a large head, a length >4.7 μm and a width >3.2 μm, and multiple flagella.

    “In macrozoospermia, the spermatozoa have a large head, a length >4.7 µm and a width >3.2 µm, and multiple flagella (6).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [6] World Health Organization. WHO Laboratory Manual for the Examination and Processing of Human Semen. 5th edition. Geneva: WHO Press, 2010.

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Menkveld et al. proposed a Tygerberg strict criteria based on detailed observation of spermatozoa, particularly from the postcoital cervical mucus.

    “Menkveld et al., in later years, proposed a Tygerberg strict criteria based on detailed observation of spermatozoa, particularly from the postcoital cervical mucus (27).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [27] Menkveld R Stander FS Kotze TJ The evaluation of morphological characteristics of human spermatozoa according to stricter criteria. Hum Reprod 1990; 5: 586- 92. 10.1093/oxfordjournals.humrep.a137150 2394790 source

  • May combine two claims.

    Premisenone given

    Tail defects are critical and can result in asthenozoospermia or abnormal motility.

    “Tail defects are critical and can result in asthenozoospermia or abnormal motility.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Other sperm morphology classifications exist, but they are not accepted globally and are used in certain countries only.

    “Aside from the classification used by the WHO, other sperm morphology classifications also exist. However, they are not accepted globally but are used in certain countries only (33,34).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [33] Auger J Eustache F Andersen AG Sperm morphological defects related to environment, lifestyle and medical history of 1001 male partners of pregnant women from four European cities. Hum Reprod 2001; 16: 2710- 7. 10.1093/humrep/16.12.2710 11726600 source
    • cites [34] Blanchard M Haguenoer K Apert A Sperm morphology assessment using David’s classification: time to switch to strict criteria? Prospective comparative analysis in a selected IVF population. Int J Androl 2011; 34: 145- 52. 10.1111/j.1365-2605.2010.01066.x 20497261 source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    In the fourth edition, the cut-off was used with a statement that multicenter investigations were ongoing and that the data suggested a decrease in IVF when the proportion of normal morphology was under 15%.

    “Notably, in the fourth edition, the cut-off was used with a statement that multicenter investigations were ongoing and that the data suggested a decrease in in vitro fertilization (IVF) when the proportion of normal morphology was under 15% (11).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [11] World Health Organization. WHO Laboratory manual for the examination of human semen and sperm-cervical mucus interaction. 4th edition. Cambridge: Cambridge University Press, 1999.

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S2 (checkable). May combine two claims.

    Interpretationreasoning

    For every study or article, a detailed method of sperm morphological assessment and the criteria used should be considered and cannot be directly compared to the findings of another study.

    “Therefore, for every study or article, a detailed method of sperm morphological assessment and the criteria used should be considered and cannot be directly compared to the findings of another study.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The third edition of the WHO Manual in 1992 was the first to apply strict criteria for sperm morphology using a cut-off of 30% for normal morphology.

    “The third edition of the WHO Manual in 1992 was the first to apply strict criteria for sperm morphology using a cut-off of 30% for normal morphology, which was continually decreased in the later editions (10).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [10] World Health Organization. WHO Laboratory manual for the examination of human semen and sperm-cervical mucus interaction. 3rd edition. Cambridge: Cambridge University Press, 1992.

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

    Premisecitation

    Compared to the third edition, the fifth edition has a better definition of normal spermatozoa and sperm abnormalities.

    “Compared to the third edition, the fifth edition has a better definition of normal spermatozoa and sperm abnormalities (6).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [6] World Health Organization. WHO Laboratory Manual for the Examination and Processing of Human Semen. 5th edition. Geneva: WHO Press, 2010.

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Classified as probably not a substantial claim.

    Interpretationnone given

    There is no absolute recommendation available for isolated teratozoospermia.

    “However, there is no absolute recommendation available for isolated teratozoospermia.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationnone given

    There is no clear evidence whether severe or moderate teratozoospermia compromises chances of natural pregnancy, or whether it is a contra-indication for IUI or IVF.

    “There is no clear evidence whether severe or moderate teratozoospermia compromises chances of natural pregnancy, or whether it is a contra-indication for IUI or IVF.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Interpretationreasoning

    The need for and role of ART for isolated teratozoospermia is controversial.

    “The need for, and role of, ART for isolated teratozoospermia is also controversial, and other factors—female fertility status, comorbidities, duration of infertility, etc.—should be considered when deciding whether IUI or ART (IVF/ICSI) is required in a couple with isolated teratozoospermia as the only male factor.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The sixth edition of the WHO manual on human semen examination recommends morphological assessment by strict criteria.

    “The sixth edition of the WHO manual on human semen examination recommends morphological assessment by strict criteria.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [5] World Health Organization. WHO Laboratory Manual for the Examination and Processing of Human Semen. 6th edition. Geneva: WHO Press, 2021.

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationnone given

    There is considerable controversy about the diagnostic utility and predictive value of strict morphological assessment.

    “However, there is considerable controversy about the diagnostic utility and predictive value of such a morphological assessment.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    In a retrospective study of 80 patients, only 20% of operated patients had significant benefits after varicocelectomy, with their mean morphology improving from 1.3% to 9.1%.

    “Another retrospective study on 80 patients found that only 20% of operated patients had significant benefits after varicocelectomy, with their mean morphology improving from 1.3% to 9.1% (102).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [102] Choe JH Seo JT. Is Varicocelectomy Useful for Subfertile Men with Isolated Teratozoospermia? Urology 2015; 86: 1123- 8. 10.1016/j.urology.2015.08.014 26341572 source

  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationnone given

    There is a lack of recommendations from professional societies and controversies in contemporary literature regarding isolated teratozoospermia.

    “due to the lack of recommendations from professional societies and controversies in contemporary literature.”
    Quote in the paperSubstantial claim
57 of 57

  • The paper relies on this without support.

    At present, there are no guidelines available for the treatment of isolated teratozoospermia.

    “At present, there are no guidelines available for the treatment of isolated teratozoospermia.”

  • The paper relies on this without support.

    Abnormal sperm shape is linked to oxidative stress and the integrity of sperm DNA and chromatin.

    “However, given the strong evidence linking abnormal sperm shape, oxidative stress, and the integrity of sperm DNA and chromatin, there is a role for therapy to try and increase the percentage of normal sperm morphology.”
2 of 2

Cites

Flagged first, then by citations

Research works printed but not linked: 6

  1. [5]World Health Organization. WHO Laboratory Manual for the Examination and Processing of Human Semen. 6th edition. Geneva: WHO Press, 2021.
  2. [6]World Health Organization. WHO Laboratory Manual for the Examination and Processing of Human Semen. 5th edition. Geneva: WHO Press, 2010.
  3. [8]World Health Organization. Laboratory manual for the examination of human semen and semen-cervical mucus interaction. Singapore: Press Concern, 1980.
  4. [9]World Health Organization. WHO Laboratory manual for the examination of human semen and semen-cervical mucus interaction. 2nd edition. Cambridge: Cambridge University Press, 1987.
  5. [10]World Health Organization. WHO Laboratory manual for the examination of human semen and sperm-cervical mucus interaction. 3rd edition. Cambridge: Cambridge University Press, 1992.
  6. [11]World Health Organization. WHO Laboratory manual for the examination of human semen and sperm-cervical mucus interaction. 4th edition. Cambridge: Cambridge University Press, 1999.

Cited by

Sorted by citations

Related

Authors
Atmoko, W., Savira, M., Shah, R., Chung, E., & Agarwal, A.
Affiliations
  • University of Indonesia (ID)
  • Lilavati Hospital & Research Centre (IN)
  • The University of Queensland (AU)
  • Cleveland Clinic (US)
Corresponding author
Agarwal, Ashok
ORCID
Venue
Translational Andrology and Urology
Publisher
AME Publishing Company
Published
2024-02
Volume
13
Issue
2
Pages
260-273
ISSN
  • 2223-4683 (ISSN-L)
  • 2223-4691
DOI
10.21037/tau-23-397
PMC
PMC10932644
OpenAlex
W4392194026
Cited by
23
References
97
Citations by year
2026: 10 · 2025: 13
FWCI
2.28
Type
journal article
Language
en
Open access
Licence
cc-by-nc-nd
Locations
  • Translational Andrology and Urology (publishedVersion, cc-by-nc-nd)
  • PubMed (publishedVersion)
  • PubMed Central (submittedVersion, cc-by-nc-nd)
Topics
  • Health Sciences › Medicine › Reproductive Medicine › Sperm and Testicular Function
  • Health Sciences › Health Professions › General Health Professions › Male Reproductive Health Studies
  • Health Sciences › Medicine › Reproductive Medicine › Reproductive Health and Technologies
Keywords
male infertility, sperm morphology, sperm DNA damage, oxidative stress, varicocele, assisted reproduction outcomes, intrauterine insemination, spermatogenesis, fertility prediction, antioxidants, idiopathic male infertility

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Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-26.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-26.

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