The Effect of Ejaculatory Abstinence Interval on Sperm Parameters and Clinical Outcome of ART. A Systematic Review of the Literature

Association of abstinence time with semen quality and fertility outcomes: a systematic review and dose-response meta-analysis

BACKGROUND

Infertility affects 186 million people worldwide, with male factors contributing to 50% of infertility cases. Semen analysis is a key for diagnosing male factor infertility, but sperm parameters can be influenced by ejaculatory abstinence (EA) duration. Shortening or prolonging EA can impact on semen quality and assisted reproductive technology (ART) outcomes, but the optimal EA duration remains unclear, particularly for infertility patients.

OBJECTIVES

This study conducts a comprehensive meta-analysis to explore the impact of varying abstinence durations on semen quality and fertility outcomes.

METHODS

Three English database (PubMed, Embase, and Cochrane Central Register of Controlled Trials) as well as four Chinese database (China National Knowledge Infrastructure, Chinese Scientific Journals database, WanFang database, and Chinese Biomedical Literature database) were searched from 2000 to August 2023. The classical meta-analysis and "one-stage" dose-response meta-analysis were conducted to compare the associations of different abstinence durations (short-term abstinence vs. long-term abstinence) on semen quality in healthy adult and different type of infertile patients.

RESULTS

There were 85 eligible studies were finally included. The meta-analysis of volume (mean difference [MD] = -0.95 mL, 95% confidence interval [CI]: -1.16 to -0.74 mL), total sperm count (TSC) (MD = -102.45×106, 95% CI: -117.98×106 to -86.91×106), sperm concentration (SC) (MD = -11.88×106/mL, 95% CI: -18.96×106/mL to -4.80×106/mL), DNA fragmentation index (DFI) (MD = -2.37%, 95% CI: -4.73% to -0.01%) in healthy men showed a significant decrease with different abstinence durations (short-term abstinence vs. long-term abstinence). The meta-analysis of infertile men showed significant decrease in volume in various subgroups (MD range: -0.73 to -1.17 mL) with P < 0.01; TSC (MD = -61.93×106, 95% CI: -88.84×106 to -35.01×106), SC (MD = -5.39×106/mL, 95% CI: -9.97×106 to -0.81×106/mL), DFI (MD = -5.63%, 95% CI: -10.19% to -1.06%) in unexplained infertility subgroup; significant increase in viability (MD = 6.14%, 95% CI: 3.61% to 8.68%) in the unexplained infertility subgroup. The dose-response meta-analysis showed that TSC in oligozoospermia showed a nonlinear increase (coefficient from 3.38 to -5.76, P from 0.02 to 0.22) and the truncation point was around the 4th to 5th abstinence day. The percentage of progressive motile sperm (PR) in asthenozoospermia showed a significant decrease (coefficient = -2.39, 95% CI: -4.28 to -0.50). For fertility outcomes of different ARTs, only the clinical pregnancy rate (CPR) in the intrauterine insemination (IUI) subgroup showed a significant decrease around the 3rd day (coefficient = 0.85, 95% CI: 0.75 to 0.97).

CONCLUSIONS

Short-term abstinence may be associated with limited improvements in semen quality in healthy men but could be more beneficial for infertile men, especially within the first 4 days of abstinence. Caution is urged in making definitive conclusions about the causal relationship between abstinence time and semen quality changes due to potential confounding and interactions.

Effect of ejaculatory abstinence period on fertilization and clinical outcomes in ICSI cycles: a retrospective analysis

RESEARCH QUESTION

Does ejaculatory abstinence impact fertilization outcomes in intracytoplasmic sperm injection (ICSI) cycles in infertile couples?

DESIGN

This single-centre retrospective observational study included 6919 ICSI cycles from 2013 to 2022. The primary outcome was the assessment of oocyte fertilization, measured in terms of the rate of formation of two-pronuclear (2PN), 3PN and 1PN zygotes. Secondary outcomes were blastulation, cumulative positive β-human chorionic gonadotrophin test and clinical pregnancy rates. Relationships between ejaculatory abstinence and fertilization outcomes, and ejaculatory abstinence and clinical outcomes were evaluated with multivariable analysis, including possible confounders.

RESULTS

A positive association was observed between ejaculatory abstinence and semen sample volume (P < 0.001), sperm concentration (P < 0.001) and total motile sperm count (P < 0.001). No association was found between the 1PN zygote rate and ejaculatory abstinence (P = 0.97). Conversely, for each additional day of ejaculatory abstinence, the likelihood of obtaining 2PN zygotes from all inseminated oocytes decreased by 3% [adjusted odds ratio (aOR) 0.97, 95% CI 0.94-0.99], whilst the likelihood of obtaining 3PN zygotes from all inseminated oocytes increased significantly by 14% (aOR 1.14, 95% CI 1.07-1.22). No significant associations were found between ejaculatory abstinence and blastulation, cumulative pregnancy or miscarriage rates.

CONCLUSIONS

A longer ejaculatory abstinence period significantly decreases the rate of 2PN zygotes, and increases the rate of 3PN zygotes without directly affect blastulation and pregnancy rates.

Technical Aspects and Clinical Limitations of Sperm DNA Fragmentation Testing in Male Infertility: A Global Survey, Current Guidelines, and Expert Recommendations

PURPOSE

Sperm DNA fragmentation (SDF) is a functional sperm abnormality that can impact reproductive potential, for which four assays have been described in the recently published sixth edition of the WHO laboratory manual for the examination and processing of human semen. The purpose of this study was to examine the global practices related to the use of SDF assays and investigate the barriers and limitations that clinicians face in incorporating these tests into their practice.

MATERIALS AND METHODS

Clinicians managing male infertility were invited to complete an online survey on practices related to SDF diagnostic and treatment approaches. Their responses related to the technical aspects of SDF testing, current professional society guidelines, and the literature were used to generate expert recommendations via the Delphi method. Finally, challenges related to SDF that the clinicians encounter in their daily practice were captured.

RESULTS

The survey was completed by 436 reproductive clinicians. Overall, terminal deoxynucleotidyl transferase deoxyuridine triphosphate Nick-End Labeling (TUNEL) is the most commonly used assay chosen by 28.6%, followed by the sperm chromatin structure assay (24.1%), and the sperm chromatin dispersion (19.1%). The choice of the assay was largely influenced by availability (70% of respondents). A threshold of 30% was the most selected cut-off value for elevated SDF by 33.7% of clinicians. Of respondents, 53.6% recommend SDF testing after 3 to 5 days of abstinence. Although 75.3% believe SDF testing can provide an explanation for many unknown causes of infertility, the main limiting factors selected by respondents are a lack of professional society guideline recommendations (62.7%) and an absence of globally accepted references for SDF interpretation (50.3%).

CONCLUSIONS

This study represents the largest global survey on the technical aspects of SDF testing as well as the barriers encountered by clinicians. Unified global recommendations regarding clinician implementation and standard laboratory interpretation of SDF testing are crucial.

Short-interval second ejaculation improves sperm quality, blastocyst formation in oligoasthenozoospermic males in ICSI cycles: a time-lapse sibling oocytes study

Background

Does short-interval second ejaculation improve sperm quality, embryo development and clinical outcomes for oligoasthenozoospermia males received intracytoplasmic sperm injection (ICSI) treatment?

Methods

All enrolled male patients underwent short-interval secondary ejaculation on the day of oocyte retrieval, and 786 sibling MII oocytes from 67 cycles were equally divided into two groups based on whether the injected spermatozoons originated from the first or second ejaculation. Semen parameters, embryo development efficiency, morphokinetic parameters and clinical outcomes were compared between the two groups to assess the efficiency and clinical value of short-interval second ejaculation in ICSI cycles.

Results

Short-interval second ejaculation significantly improved sperm motility, normal morphological rate, and sperm DNA integrity both before and after sperm swim-up. The high-quality blastocyst rate (24.79% versus 14.67%), available blastocyst rate (57.56% versus 48.44%), and oocyte utilization rate (52.93% versus 45.29%) were significantly higher in the second ejaculation group (P<0.05). The clinical pregnancy rate (59.09% versus 47.37%), implantation rate (42.11% versus 32.35%) and live birth rate (40.91% versus 31.58%) were higher in the second ejaculation group, but the differences were not significant (P>0.05). Time-lapse analysis showed that morphokinetic time points after the 7-cell stage were earlier in the second ejaculation group but without a significant difference (P>0.05), and abnormal embryo cleavage patterns between the two groups were not significantly different (P>0.05).

Conclusions

Short-interval second ejaculation significantly improves sperm quality in oligoasthenozoospermic males, and is beneficial for blastocyst formation efficiency in ICSI cycles. This study suggested a non-invasive and simple but effective strategy for improving ICSI treatment outcomes.

The Variability of Semen Parameters With Sexual Abstinence Using Mail-in Sperm Testing Is Similar to That Seen With Traditional In-Office Semen Analysis

The impact of ejaculatory abstinence on semen parameters using in-office semen analyses has been well-established; however, their variability has not been evaluated in men using mail-in semen analysis kits. Our study aims to describe how the sperm parameters using mail-in semen analysis tests change with abstinence and validate their equivalence to those seen with in-office semen analysis tests. We retrospectively reviewed the semen analysis results of men using mail-in semen analysis tests provided by Give Legacy, Inc (Legacy) facilities from 2019 to 2021. We collected their demographic information, abstinence duration, and semen parameters (conventional and kinematic) from their records. Semen samples were categorized as normozoospermic and oligozoospermic based on concentration. The shape of the relationship between abstinence duration and semen parameters was assessed via generalized additive models. We have collected 3,469 unique samples provided by 2,609 (75%) normozoospermic men and 860 (25%) oligozoospermic from all over the United States. In normozoospermic men, longer periods of sexual abstinence were linked to higher levels of sperm concentration, total sperm count, and total motile sperm. However, there was a decline in both total and progressive motility. Conversely, in oligozoospermic men, extended periods of abstinence led to a rapid decline in total motile sperm, as well as total and progressive motility. There was no significant correlation observed between sexual abstinence and variations in sperm morphology. Our study shows that variability of sperm parameters with abstinence, as measured through mail-in semen analysis tests, is comparable to the patterns observed with conventional in-office sperm testing.

Trends in sperm quality by computer-assisted sperm analysis of 49,189 men during 2015-2021 in a fertility center from China

Background

Sperm quality, including semen volume, sperm count, concentration, and total and progressive motility (collectively, "semen parameters"), has declined in the recent decades. Computer-assisted sperm analysis (CASA) provides sperm kinematic parameters, and the temporal trends of which remain unclear. Our objective is to examine the temporal trend of both semen parameters and kinematic parameters in Shanghai, China, in the recent years.

Methods

This retrospective study analyzed semen parameters and kinematic parameters of 49,819 men attending our reproductive center by using CASA during 2015-2021. The total sample was divided into two groups: samples that surpassed the WHO guideline (2010) low reference limits ("above reference limit" group, ARL; n = 24,575) and samples that did not ("below reference limit" group, BRL; n = 24,614). One-way analysis of variance, Kruskal-Wallis test, independent samples t-test, and covariance analysis were used to assess the differences among groups. Year, age, and abstinence time were included in the multiple linear regression model of the ARL group to adjust the confounders and depict the trends in sperm quality.

Results

Among all the total sample and the ARL and BRL groups, the age of subjects increased in recent years. Semen volume and sperm count showed declined tendency with years in the total sample, the ARL and BRL groups, and the subgroup of age or abstinence time, whereas sperm velocities showed increased tendency with years on the contrary. The multiple linear regression model of the ARL group, adjusting for age and abstinence time, confirmed these trends. Semen volume (β1= -0.162; CI: -0.172, -0.152), sperm count (β1= -9.97; CI: -10.813, -9.128), sperm concentration (β1 = -0.535; CI: -0.772, -0.299), motility (β1 = -1.751; CI: -1.830, -1.672), and progressive motility (β1 = -1.12; CI: -0.201, -0.145) decreased with year, whereas curvilinear line velocity (VCL) (β1 = 3.058; CI: 2.912, 3.203), straight line velocity (VSL) (β1 = 2.075; CI: 1.990, 2.161), and average path velocity (VAP) (β1 = 2.305; CI: 2.224, 2.386) increased over time (all p < 0.001). In addition, VCL, VSL, and VAP significantly declined with age and abstinence time.

Conclusion

The semen parameters declined, whereas the kinematic parameters increased over the recent years. We propose that, although sperm count and motility declined over time, sperm motion velocity increased, suggesting a possible compensatory mechanism of male fertility.

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

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

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

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

Advanced sperm tests and impact on clinical male factor management

PURPOSE OF REVIEW

Although semen analysis remains a cornerstone of male fertility evaluation, conventional semen analysis parameters do not assess for DNA integrity or functional capacity of sperm. Sperm DNA fragmentation (SDF) and sperm aneuploidy tests have been utilized as adjunct tools to distinguish fertile and infertile men and predict pregnancy outcomes. This review serves as an update on indications and utility of advanced sperm tests, as well as associated controversies and limitations.

RECENT FINDINGS

Elevated SDF is associated with prolonged time to pregnancy, lower chance of spontaneous pregnancy, and lower live birth rates. Sperm aneuploidy is more frequent in infertile men, in male partners of couples experiencing recurrent pregnancy loss, and recurrent failure of assisted reproductive technology (ART). These tests can, therefore, provide important information to guide management and counseling of infertile couples to optimize reproductive outcomes.

SUMMARY

We evaluated data surrounding SDF and sperm aneuploidy tests, which are utilized both within and beyond the scope of AUA/ASRM guidelines. While the tests at hand require further standardization and randomized controlled studies, the current data suggest strong associations with pregnancy outcomes and can be utilized to counsel and manage infertile males.

Sperm DNA fragmentation testing in clinical management of reproductive medicine

Background

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

Methods

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

Main Findings

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

Conclusion

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

Optimizing outcomes for men with severe infertility

PURPOSE OF REVIEW

To evaluate recent evidence related to optimizing outcomes for men with severe infertility, including effect of ejaculatory abstinence interval on semen parameters and assisted reproductive technology (ART) outcomes, and impact of cryopreservation on surgically retrieved testicular sperm obtained from men with nonobstructive azoospermia (also referred to as azoospermia due to spermatogenic dysfunction).

RECENT FINDINGS

Recent evidence strongly suggests that a short abstinence interval improves sperm motility and ART outcomes. Similarly, recent studies have concluded that using fresh vs. frozen testicular sperm results in higher live birth rates.

SUMMARY

Although the World Health Organization currently recommends a 2- to 7-day ejaculatory abstinence period, this interval is based more on the need to standardize semen parameters than clinical outcomes. In fact, recent evidence suggests that shorter abstinence consistently improves sperm motility and ART outcomes for infertile men. Similarly, recent studies have reported an improvement in live birth rates with fresh (vs. frozen) testicular sperm, though their retrospective design and lack of intention to treat analyses makes it difficult to draw strong conclusions. Although additional, well designed studies are needed, providers may be able to leverage these techniques in their practice to improve outcomes for some infertile men.

Longitudinal semen parameter assessments and live birth: variability and implications for treatment strategies

OBJECTIVE

To examine whether semen parameters are associated with live birth among couples seeking infertility treatment after accounting for semen parameter variability.

DESIGN

Folic Acid and Zinc Supplementation Trial (FAZST) prospective cohort.

SETTING

Four US reproductive endocrinology and infertility care study centers, 2013-2017.

PATIENT(S)

Couples (n = 2,369) seeking fertility consultations at 4 US infertility care study centers.

INTERVENTION(S)

Semen volume, pH, sperm viability, morphology, progressive and total motility, concentration, count, and total and progressive motile count assessed at baseline and at 2, 4, and 6 months after enrollment.

MAIN OUTCOME MEASURE(S)

Log-binomial models stratified by fertility treatment received (in vitro fertilization [IVF], intrauterine insemination [IUI], ovulation induction [OI], or no treatment) estimated risk differences (RDs) between semen parameter quartiles and live birth and accounted for multiple semen assessments per person. We accounted for abstinence time, the biological interdependence of semen parameters, and potential selection bias because of loss to follow-up.

RESULT(S)

Among couples using OI only or no treatment, 39% had a live birth, and relative to the highest quartile, the lowest quartiles of morphology (RD, -19 [95% CI, -23 to -15] per 100 couples), motility (RD, -13 [95% CI, -17 to -9]), concentration (RD, -22 [95% CI, -26 to -19]), and total motile count (RD, -18 [95% CI, -22 to -14]) were associated with fewer live births. For IUI, 26% had a live birth, and the lowest quartiles of volume (RD, -6 [95% CI, -11 to -0.4]), concentration (RD, -6 [95% CI, -11 to -0.1]), count (RD, -10 [95% CI, -15 to -4]), and total motile count (RD, -7 [95% CI, -13 to -1]) were associated with fewer live births. For IVF, 61% had a live birth, and only morphology (Q1 RD, -7 [95% CI, -14 to 0.2]; Q2 RD, -10 [95% CI, -17 to -2.2]) was associated with live birth.

CONCLUSION(S)

Semen parameters are critical in couples undergoing OI/IUI. Only low morphology was important for live birth after IVF. Although data supporting the use of semen parameters are fragmented across differing populations, current findings are generalizable across the range of male fertility and couple fertility treatments, providing evidence about which semen parameters are most relevant in which settings.

CLINICAL TRIAL REGISTRATION NUMBER

NCT#01857310.

mRNA and Viral Vector COVID-19 Vaccines Do Not Affect Male Fertility: A Prospective Study

PURPOSE

To assess whether mRNA and viral vector coronavirus disease 2019 (COVID-19) vaccines detrimentally affected semen parameters.

MATERIALS AND METHODS

In this prospective study, we enrolled 101 men vaccinated for COVID-19 (76% received mRNA vaccines, 20% viral vector vaccines, 2% a mixed formulation, and for 2 men no information about vaccine type was available) in 2021 and with a previous semen analysis. For each man we compared semen parameters before and after vaccination.

RESULTS

Post-vaccine samples were obtained at a median of 2.3±1.5 months after the second dose. After vaccination, the median sample volume significantly decreased (from 3.0 to 2.6 mL, p=0.036), whereas the median sperm concentration, the progressive motility, and total motile sperm count increased (from 25.0 to 43.0 million/mL, p<0.0001; from 50% to 56%, p=0.022; from 34.8 to 54.6 million, p<0.0001, respectively). Thirty-four patients were oligospermic before the vaccine, and also in these patients we observed a significant increase of sperm parameters after vaccine. Finally, we confirmed the aforementioned results in men who received a mRNA or a viral vector vaccine.

CONCLUSIONS

The semen parameters following COVID-19 vaccination did not reflect any causative detrimental effect from vaccination, and for the first time we demonstrated that this applies to both mRNA and viral-vector vaccines. The known individual variation in semen and the reduced abstinence time before the post-vaccine sample collection may explain the increases in sperm parameters.

In vitro maturation of human oocytes maintaining good development potential for rescue intracytoplasmic sperm injection with fresh sperm

BACKGROUND

The outcomes of the use of commercial in vitro maturation (IVM) medium to culture immature oocytes obtained from conventional ovulation induction, followed by rescue intracytoplasmic sperm injection (RICSI), are not ideal. It is thus difficult to widely adopt this approach in clinical practice. Therefore, it is necessary to explore methods for improving the clinical outcome of IVM.

AIM

To study the effect of sperm on the developmental potential of in vitro-matured oocytes in conventional culture.

METHODS

This was a retrospective study of patients whose immature oocytes were harvested from conventional oocyte stimulation cycles and underwent ICSI at our hospital between June 2018 and August 2020. RICSI was performed using sperm collected on the day of oocyte harvest (old) and sperm collected on the day of RICSI (fresh) and oocytes matured in vitro after 24 h of culture in conventional medium. The rates of in vitro oocyte maturation, normal fertilization, normal cleavage, day-3 top-quality embryos, and useful blastocyst formation were compared between the two groups.

RESULTS

In total, 102 germinal vesicle (GV)-stage immature oocytes were cultured in the old sperm group. In the fresh sperm group, 122 GV-stage immature oocytes were collected and cultured in vitro for 24 h. There were no significant differences in the general conditions of males and females between the two groups (P > 0.05). The oocyte maturation, normal fertilization, and normal cleavage rates of the old and fresh groups were 51.0% vs 55.7%, 61.5% vs 64.7%, and 93.8% vs 93.2%, respectively. None of the rates differed significantly (P > 0.05) between the two groups. However, the day-3 top-quality embryo and useful blastocyst rates of the old and fresh sperm groups were 16.6% vs 63.4%; 6.67% vs 34.6%, respectively. The day-3 top-quality embryos and useful blastocyst rates of the old sperm group were significantly lower than those of the fresh group (P < 0.05).

CONCLUSION

In vitro maturation with conventional culture medium combined with the use of fresh sperm collected on the day of RICSI is an easy-to-implement strategy for patients whose oocytes are completely or mostly immature.