***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    ***EXAMPLES*** 
    Input: One of the causes of failure in ART is sperm DNA fragmentation which may be associated with long period of spermatozoa incubation at 37 ° C . The objective was to evaluate the rate of sperm DNA fragmentation using the sperm chromatin dispersion ( SCD ) test after swim‐up at different time intervals prior to use . In this prospect i ve study , 21 normozoospermic specimens were analysed . The sample s were incubated at 37 ° C after preparation by direct swim‐up .  DNA fragmentation was assessed at different time intervals ( 0 , 1 , 2 and 3 h ) using SCD test . Spermatozoa with no DNA fragmentation showed large‐ or medium‐sized halos , and sperm cells with DNA fragmentation showed either a small halo or no halo . The rates of normal morphology and progressive motility after sperm processing were 72.33 ± 2.53 % and 90 ± 1.02 % , respectively . The rate of sperm DNA fragmentation was significantly higher after 2 h ( 8.81 ± 0.93 % , P = 0.004 ) and 3 h ( 10.76 ± 0.89 % , P < 0.0001 ) of incubation compared to 0 h ( 4.38 ± 0.8 % ) . A positive correlation was found between the incubation time and sperm DNA damage ( P < 0.0001 ) . Prolonged incubation of prepared normozoospermic sample s at 37 ° C is associated with higher rates of sperm DNA fragmentation . Therefore , sperm sample s intended for ART procedures should be used within 2 h of incubation at 37 ° C OBJECTIVE To examine sperm DNA fragmentation in semen used for assisted reproduction procedures to establish this factor 's prognostic role in fertilization rate , embryo development , pregnancy rate , and outcome . DESIGN Prospect i ve study . SETTING Department of Medicine and Biology of Reproduction of the Edouard Herriot Hospital in Lyon , France . PATIENT(S ) 322 couples , divided into 88 cycles of in vitro fertilization ( IVF ) or 234 cycles of intracytoplasmic sperm injection ( ICSI ) .  INTERVENTION(S ) Sperm DNA fragmentation was detected in sperm obtained 2 to 5 months before the ART procedure . MAIN OUTCOME MEASURE(S ) Sperm DNA fragmentation was measured with the  terminal deoxynucleotidyl transferase-mediated digoxigenin-dUTP nick-end labeling ( TUNEL ) technique .  RESULT ( S ) There was a negative statistical correlation between the rate of fragmentation and the semen characteristics . A statistically significant negative relationship was found for sperm DNA fragmentation and fertilization when ICSI and IVF were compared . With ICSI , a statistically significant negative relationship was found between fertilization rate and percentage of sperm DNA fragmentation ( DNA fragmentation index , or DFI ) . The risk of nontransfer due to blocked embryo development increased when the DFI exceeded 15 % ( 18.2 % for ICSI vs 4.2 % for IVF ) with an odds ratio of 5.05 . The miscarriage risk increased fourfold when the DFI exceeded 15 % ( 37.5 % for ICSI vs 8.8 % for IVF ) . CONCLUSION ( S ) Sperm DNA fragmentation measured 2 to 5 months before the assisted reproduction procedure was a prognostic indicator of the fertilization , pregnancy , and miscarriage rates and the pregnancy outcome BACKGROUND We aim ed to investigate whether sperm DNA quality may predict intrauterine insemination ( IUI ) outcome . METHODS The study was design ed in a prospect i ve cohort fashion , at a tertiary centre for reproductive medicine . A total of 119 patients underwent 154 cycles of IUI .  Parameters related to demography , cycle management and semen sample used for IUI were evaluated . Conventional semen parameters , morphology ( strict criteria ) , sperm DNA fragmentation and stability [ evaluated by terminal deoxynucleotidyl transferase-mediated dUDP nick-end labelling ( TUNEL ) and acridine orange staining under both acid and acid + heat denaturing conditions respectively ] were measured . The main outcome measure was clinical pregnancy , defined as ultrasonographic visualization of intrauterine gestational sac(s ) . RESULTS Logistic regression analyses were done on six sets of data , including all cycles combined , cycles with washed sample s , first cycle of each couple , first cycle of each couple with washed sample s , cycles stimulated with gonadotrophins and finally gonadotrophin-stimulated cycles with washed sample s. The number of pre-ovulatory follicles on day of hCG , the age of the woman and the percentage of sperm with acid- + heat-resistant DNA were the parameters that predicted IUI outcome in most of these data subsets . For the gonadotrophin-stimulated cycles , age of the man appeared as a predictor as opposed to that of the woman ; and for the cycles within this subgroup , where the semen sample was washed , sperm DNA fragmentation and age of the man were the only two parameters to predict IUI outcome . No sample s with > 12 % of sperm having DNA fragmentation result ed in pregnancy . CONCLUSIONS The number of follicles , age of the woman/man and sperm DNA quality may predict IUI outcome OBJECTIVES To st and ardize the TUNEL assay by establishing inter- and intraobserver variability , interassay variability , cutoff values , sensitivity and specificity of the assay , and study ing the distribution of the DNA damage in a population of infertile men referred to a clinical and rology laboratory . METHODS Seminal ejaculates from 25 healthy male volunteers ( controls ) and 194 infertile men ( with male factor infertility ) referred to an and rology laboratory were examined for DNA damage by TUNEL assay using flow cytometric analysis . RESULTS Both the inter- and intraobserver variability and interassay variability was small ( < 10 % ) . DNA damage in the controls was 11.9 ± 6.8 % vs. 29.5 ± 18.7 % in patients ( P < .001 ) . The cut-off value of 19.25 % maximized the observed sensitivity ( 64.9 % ) and specificity ( 100 % ) of the assay . The distribution of DNA damage in the patients was as follows : 14.9 % ( 29 of 194 ) with DNA damage between 0 % and 10 % ; 22.7 % ( 44 of 194 ) between 10 % and 20 % ; 8.8 % ( 17 of 194 ) between 20 % and 30 % ; and 17.5 % ( 34 of 194 ) between 30 % and 40 % . Finally , 27.3 % ( 53 of 194 ) had TUNEL values > 40 % . CONCLUSIONS We report a detailed st and ardization of the TUNEL assay for clinical use , as well as reference ranges for DNA damage in normal healthy donors and infertile men . A cut-off of 19.25 % with observed 100 % specificity established in our program can differentiate infertile men with DNA damage from healthy men . This test can be offered to infertile patients who are idiopathic , have severe oxidative stress-related abnormal semen quality , and contribute to the infertility problem of the couple who are considering assisted reproductive techniques Testicular and epididymal spermatozoa are used routinely for intracytoplasmic sperm injection ( ICSI ) to treat men with obstructive azoospermia . Little is known of the effects of obstruction and stasis on the DNA of these spermatozoa , particularly in the epididymis where spermatozoa have been retained for long periods . Surgical epididymal aspiration for ICSI could provide spermatozoa that are senescent or dying . Using the Comet assay , the percentage of undamaged DNA of testicular spermatozoa from 20 men with obstructive azoospermia was significantly better ( 83.0 + /- 1 . 2 % ) than from proximal epididymal spermatozoa ( 75.4 + /- 2.3 % ; P < 0 . 05 ) . There was no difference between the percentage of undamaged DNA of testicular spermatozoa from 39 men with obstructive azoospermia ( 84.0 + /- 0.9 ) or from 10 fertile men at vasectomy ( 86.8 + /- 1.8 ) or from ejaculated spermatozoa from five of the controls ( 78.9 + /- 3.9 ; P > 0.05 ) . In nine subjects , a second biopsy was carried out 6 months later . There was no significant difference in undamaged DNA on these two occasions ( 83.5 + /- 5.6 and 84.1 + /- 4.2 ; P > 0.05 ) . This confirms the reproducibility of the Comet assay for non-ejaculated spermatozoa . Our data suggest that testicular sperm DNA appears to be significantly less damaged than epididymal sperm DNA , and so testicular spermatozoa should be used in preference for ICSI to treat men with obstructive azoospermia OBJECTIVE : To estimate the effects of aging on the percentage of outwardly healthy couples who are sterile ( completely unable to conceive without assisted reproduction ) or infertile ( unable to conceive within a year of unprotected intercourse ) . METHODS : A prospect i ve fecundability study was conducted in a sample of 782 couples recruited from 7 European centers for natural family planning . Women aged 18–40 years were eligible .  Daily intercourse records were used to adjust for timing and frequency of intercourse when estimating the per-menstrual-cycle probability of conception . The number of menstrual cycles required to conceive a clinical pregnancy and the probability of sterility and infertility were derived from the estimated fecundability distributions for men and women of different ages . RESULTS : Sterility was estimated at about 1 % ; this percent did not change with age . The percentage infertility was estimated at 8 % for women aged 19–26 years , 13–14 % for women aged 27–34 years and 18 % for women aged 35–39 years . Starting in the late 30s , male age was an important factor , with the percentage failing to conceive within 12 cycles increasing from an estimated 18–28 % between ages 35 and 40 years . The estimated percentage of infertile couples that would be able to conceive after an additional 12 cycles of trying varied from 43–63 % depending on age . CONCLUSION : Increased infertility  in older couples is attributable primarily to declines in fertility rates rather than to absolute sterility . Many infertile couples will conceive if they try for an additional year . LEVEL OF EVIDENCE : The aim of the present study was to evaluate consequences of cigarette smoking on male gametes . In this prospect i ve study , sperm parameters such as sperm density , motility , viability and normal morphology were measured according to the WHO criteria . In addition to these st and ard parameters , we analysed the degree of DNA fragmentation in spermatozoa using the TUNEL-assay with flow cytometry detection in 57 non-smokers and 51 smokers seeking for infertility counselling . The smoking intoxication was assessed by question naire and measured with the CO-Tester . We show that smokers ' spermatozoa have a significantly higher DNA fragmentation than non-smokers ( 32 % versus 25.9 % , p<0.01 ) . In contrast there is no significant difference in conventional parameters between smokers and non-smokers . The degree of sperm DNA fragmentation is not significantly correlated with any of the conventional parameters . These findings suggest that cigarette smoking may have deleterious effects on sperm nuclear quality and that sperm DNA fragmentation can therefore be considered as an independent parameter with diagnostic , prognostic , and strategic value in the treatment of infertility OBJECTIVE To improve awareness of the natural age-related decline in female and male fertility with respect to natural fertility and assisted reproductive technologies ( ART ) and provide recommendations for their management , and to review investigations in the assessment of ovarian aging . OPTIONS This guideline review s options for the assessment of ovarian reserve and fertility treatments using ART with women of advanced reproductive age presenting with infertility . OUTCOMES The outcomes measured are the predictive value of ovarian reserve testing and pregnancy rates with natural and assisted fertility . EVIDENCE Published literature was retrieved through search es of PubMed or Medline , CINAHL , and The Cochrane Library in June 2010 , using appropriate key words ( ovarian aging , ovarian reserve , advanced maternal age , advanced paternal age , ART ) . Results were restricted to systematic review s , r and omized controlled trials/controlled clinical trials , and observational studies . There were no date or language restrictions . Search es were up date d on a regular basis and incorporated into the guideline to December 2010 . VALUES The quality of evidence was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care . Recommendations for practice were ranked according to the method described in that report ( Table ) . BENEFITS , HARMS , AND COSTS Primary and specialist health care providers and women will be better informed about ovarian aging and the age-related decline in natural fertility and about options for assisted reproductive technology OBJECTIVE To improve awareness of the natural age-related decline in female and male fertility with respect to natural fertility and assisted reproductive technologies ( ART ) and provide recommendations for their management , and to review investigations in the assessment of ovarian aging . OPTIONS This guideline review s 
    Output:
    
Conclusion : There are pros and cons to all the available SDF assays .
TUNEL is a reliable technique with greater accuracy and as an additional diagnostic test in And rology laboratories along with basic semen analysis can predict fertility outcome , and thus direct the choice of an assisted reproductive technology procedure for infertile couples .
Also , the TUNEL assay can be used as a prognostic test and results are beneficial in deciding personalised treatment for infertile men