What advances may the future bring to the diagnosis, treatment, and care of male sexual and reproductive health?

Over the past 40 years, since the publication of the original WHO Laboratory Manual for the Examination and Processing of Human Semen, the laboratory methods used to evaluate semen markedly changed and benefited from improved precision and accuracy, as well as the development of new tests and improved, standardized methodologies. Herein, we present the impact of the changes put forth in the sixth edition together with our views of evolving technologies that may change the methods used for the routine semen analysis, up-and-coming areas for the development of new procedures, and diagnostic approaches that will help to extend the often-descriptive interpretations of several commonly performed semen tests that promise to provide etiologies for the abnormal semen parameters observed. As we look toward the publication of the seventh edition of the manual in approximately 10 years, we describe potential advances that could markedly impact the field of andrology in the future.

The past, present, and future of the semen analysis.

This month's Views and Reviews provides an added perspective to the World Health Organization laboratory manual for the examination and processing of human semen, which was recently published in the 6th edition. The first artice provides a historical context of the prior editions of the World Health Organization manuals and modifications adopted over the years. The next piece then provides additional perspectives on the methodologies used for the performance of semen analysis. The third article then examines some of the new semen analytic technologies and enhancements that have become more common over the years. Finally, the last article proposed where male reproductive testing will head in the coming years with emerging research and technologies.

Evolution of the WHO "Semen" processing manual from the first (1980) to the sixth edition (2021).

As stated clearly in all editions of the WHO Laboratory Manual for the Examination and Processing of Human Semen, the goal of the manual is to meet the growing needs for the standardization of semen analysis procedures. With constant advances in andrology and reproductive medicine and the advent of sophisticated assisted reproductive technologies for the treatment of infertility, the manual has been continuously updated to meet the need for new, evidence-based, validated tests to not only measure semen and sperm variables but also to provide a functional assessment of spermatozoa. The sixth edition of the WHO manual, launched in 2021, can be freely downloaded from the WHO website, with the hope of gaining wide acceptance and utilization as the essential source of the latest, evidence-based information for laboratory procedures required for the assessment of male reproductive function and health.

Association between urinary bisphenol A concentrations and semen quality: A meta-analytic study.

Although preclinical research has revealed disrupting effects on male reproductive functions of bisphenol A (BPA), as yet clinical studies have led to inconsistent results. The present meta­analysis aims to establish the existence and the extent of the association between BPA exposure and semen quality. A thorough search of PubMed, Scopus and Web of Science databases was carried out. Only studies reporting data from multivariable linear regression analyses (ß-coefficients with 95% CI), assessing the association between urinary levels of BPA and standard semen parameters were included. Nine studies provided information about an overall sample of 2,399 men. Only the negative association between urinary BPA levels and sperm motility reached statistical significance (pooled ß-coefficient = -0.82; 95% CI: -1.51 to -0.12, p = 0.02; Pfor heterogeneity = 0.1, I2 = 42.9%). Yet, such a significance was lost after data adjustment for publication bias, as well as at the sensitivity analysis, when each of the two studies that contributed most to the overall estimate was excluded. In conclusion, the overall estimates of data produced by clinical studies point to a clinically negligible, if any, association between urinary BPA concentrations and semen quality. Further studies in workers at high risk of occupational exposure are warranted to corroborate the herein revealed weak correlation with a worse sperm motility.

Long-term male fertility after treatment with radioactive iodine for differentiated thyroid carcinoma.

CONTEXT: Whilst radioactive iodine (RAI) is often administered in the treatment for differentiated thyroid carcinoma (DTC), long-term data on male fertility after RAI are scarce. OBJECTIVE: To evaluate long-term male fertility after RAI for DTC, and to compare semen quality before and after RAI. DESIGN, SETTING, AND PATIENTS: Multicenter study including males with DTC ≥2 years after their final RAI treatment with a cumulative activity of ≥3.7 GBq. MAIN OUTCOME MEASURE(S): Semen analysis, hormonal evaluation, and a fertility-focused questionnaire. Cut-off scores for 'low semen quality' were based on reference values of the general population as defined by the World Health Organization (WHO). RESULTS: Fifty-one participants had a median age of 40.5 (interquartile range (IQR): 34.0-49.6) years upon evaluation and a median follow-up of 5.8 (IQR: 3.0-9.5) years after their last RAI administration. The median cumulative administered activity of RAI was 7.4 (range: 3.7-23.3) GBq. The proportion of males with a low semen volume, concentration, progressive motility, or total motile sperm count did not differ from the 10th percentile cut-off of a general population (P = 0.500, P = 0.131, P = 0.094, and P = 0.500, respectively). Cryopreserved semen was used by 1 participant of the 20 who had preserved semen. CONCLUSIONS: Participants had a normal long-term semen quality. The proportion of participants with low semen quality parameters scoring below the 10th percentile did not differ from the general population. Cryopreservation of semen of males with DTC is not crucial for conceiving a child after RAI administration but may be considered in individual cases.

Protective Effects of Fisetin in the Mice Induced by Long-Term Scrotal Hyperthermia.

Exposure to heat in the male reproductive system can lead to transient periods of partial or complete infertility. The current study aimed to examine the beneficial effects of  Fisetin against spermatogenic disorders in mice affected by long-term scrotal hyperthermia. For this purpose, hyperthermia was induced daily by exposure to the temperature of 43 °C for 20 min for 5 weeks. Except for the Healthy group, six other groups were exposed to heat stress: two treated groups including Preventive and Curative which received oral administration of fisetin (10 mg/kg/day) starting immediately before heat exposure and 15 consecutive days after the end of the heat exposure, respectively. And for each treated group, two groups including Positive Control (Pre/Cur+PC group) and vehicle (Pre/Cur+DMSO group) were considered. Our results showed that the testicular volume; the density of spermatogonia, primary spermatocyte, round spermatid, and Sertoli and Leydig cells; and sperm parameters, as well biochemical properties of the testis tissue, were remarkably higher in both Preventive and Curative groups compared to the other hyperthermia-induced groups and were highest in Preventive ones. Unlike the c-kit gene transcript which was significantly increased in the  Fisetin treatment groups (specially the Preventive group), the expression of HSP72 and NF-kß genes, Caspase3 protein, and DFI in sperm cells were significantly more decreased in Preventive and Curative groups compared to other hyperthermia-induced groups and were lowest in Preventive ones. Overall,  Fisetin exerts preventive and curative effects against spermatogenic disorders induced by long-term scrotal hyperthermia.

Lack of trusted diagnostic tools for undetermined male infertility.

Semen analysis is the cornerstone of evaluating male infertility, but it is imperfect and insufficient to diagnose male infertility. As a result, about 20% of infertile males have undetermined infertility, a term encompassing male infertility with an unknown underlying cause. Undetermined male infertility includes two categories: (i) idiopathic male infertility-infertile males with abnormal semen analyses with an unknown cause for that abnormality and (ii) unexplained male infertility-males with "normal" semen analyses who are unable to impregnate due to unknown causes. The treatment of males with undetermined infertility is limited due to a lack of understanding the frequency of general sperm defects (e.g., number, motility, shape, viability). Furthermore, there is a lack of trusted, quantitative, and predictive diagnostic tests that look inside the sperm to quantify defects such as DNA damage, RNA abnormalities, centriole dysfunction, or reactive oxygen species to discover the underlying cause. To better treat undetermined male infertility, further research is needed on the frequency of sperm defects and reliable diagnostic tools that assess intracellular sperm components must be developed. The purpose of this review is to uniquely create a paradigm of thought regarding categories of male infertility based on intracellular and extracellular features of semen and sperm, explore the prevalence of the various categories of male factor infertility, call attention to the lack of standardization and universal application of advanced sperm testing techniques beyond semen analysis, and clarify the limitations of standard semen analysis. We also call attention to the variability in definitions and consider the benefits towards undetermined male infertility if these gaps in research are filled.

Machine-learning algorithm incorporating capacitated sperm intracellular pH predicts conventional in vitro fertilization success in normospermic patients.

OBJECTIVE: To measure human sperm intracellular pH (pHi) and develop a machine-learning algorithm to predict successful conventional in vitro fertilization (IVF) in normospermic patients. DESIGN: Spermatozoa from 76 IVF patients were capacitated in vitro. Flow cytometry was used to measure sperm pHi, and computer-assisted semen analysis was used to measure hyperactivated motility. A gradient-boosted machine-learning algorithm was trained on clinical data and sperm pHi and membrane potential from 58 patients to predict successful conventional IVF, defined as a fertilization ratio (number of fertilized oocytes [2 pronuclei]/number of mature oocytes) greater than 0.66. The algorithm was validated on an independent set of data from 18 patients. SETTING: Academic medical center. PATIENT(S): Normospermic men undergoing IVF. Patients were excluded if they used frozen sperm, had known male factor infertility, or used intracytoplasmic sperm injection only. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Successful conventional IVF. RESULT(S): Sperm pHi positively correlated with hyperactivated motility and with conventional IVF ratio (n = 76) but not with intracytoplasmic sperm injection fertilization ratio (n = 38). In receiver operating curve analysis of data from the test set (n = 58), the machine-learning algorithm predicted successful conventional IVF with a mean accuracy of 0.72 (n = 18), a mean area under the curve of 0.81, a mean sensitivity of 0.65, and a mean specificity of 0.80. CONCLUSION(S): Sperm pHi correlates with conventional fertilization outcomes in normospermic patients undergoing IVF. A machine-learning algorithm can use clinical parameters and markers of capacitation to accurately predict successful fertilization in normospermic men undergoing conventional IVF.

Live Birth Rate in Patients With Premature Ovarian Insufficiency During Long-Term Follow-Up Under Hormone Replacement With or Without Ovarian Stimulation.

We analyzed data from 466 patients with premature ovarian insufficiency (POI) who wished to have a biological child and were followed up while undergoing hormone replacement (HR) therapy with or without ovarian stimulation (OS) between April 2014 and December 2020. OS was conducted in 6891 cycles in 429 patients (Group OS), whereas only HR (Group HR) was conducted in 1117 cycles in 37 patients. The follicle growth rate was 48.3% (207/429) per patient in Group OS and 5.4% (2/37) in Group HR (p<0.01). There were 51 live births (LBs) in 50 patients during follow-up. In Group OS, the LB rate was 5.8% (47/807) in cycles where in vitro fertilization (IVF) and embryo transfer were attempted (Group IVF), and 1.3% (3/236) in cycles where intrauterine insemination/timed intercourse was attempted (p<0.01). No pregnancies occurred in Group HR. Among the patients in Group IVF, the LB rate was significantly higher in patients aged <35 years at the initiation of follow-up than in patients who started at later ages (p<0.01). Among the cases who achieved an LB, 39 were patients with idiopathic POI (Group IVF-1, n=297) and seven were patients who had undergone surgical treatment for benign ovarian tumors (Group IVF-2, n=50); however, no LBs occurred in patients who had undergone treatment for malignancy (n=17), and only one in patients with chromosomal abnormalities (n=22). The LB rate per case in the patients in Group IVF-1 and those aged <35 years at the start of follow-up (Group IVF-1-a) was 24.1% (26/108), which was higher than those of the other age groups. The LB rate per case in the patients in Group IVF-1-a with <4 years of amenorrhea was 37.3% (19/51), and that in the patients in Group IVF-2 with <4 years of amenorrhea was 21.2% (7/33). These results suggest that infertility treatment is possible in some patients with POI, especially those that can be classified in Group IVF-1-a and Group IVF-2 with <4 years of amenorrhea. Therefore, OS combined with HR therapy should be considered for such patients before attempts at oocyte donation.

Is there a temporal trend in semen quality in Belgian candidate sperm donors and in sperm donors' fertility potential from 1995 onwards?

BACKGROUND: A recent meta-regression analysis reported a temporal trend in sperm count showing a significant decline in sperm count between 1973 and 2011. This decline is thought to affect fecundity. Moreover, semen quality is considered of key interest to public health given its association with all-cause male morbidity/mortality. The issue requires ongoing investigation due to geographical variation in semen quality and methodological errors in semen analysis. OBJECTIVE: To study whether there is a temporal trend in semen quality in Belgian candidate sperm donors and in sperm donors' fertility potential. MATERIALS AND METHODS: Retrospective analysis of samples provided by 439 candidate donors and pregnancy outcome in acceptors over a period of 23 years. RESULTS: A total of 807 specimens from 439 candidate donors were examined from January 1995 to December 2017 (Table S1). Sub-analyses performed with regard to TSC from 2010 onwards (weighing) revealed a significant negative trend (R2 =-0.033; ß=-0.18; CI: -0.16 to 0.07; p < 0.05). We found a statistically significant association between year of donation and morphology (R2 = 0.036; ß= -0.19; CI: -0.26 to -0.08; p < 0.0001). The mean (±SD) clinical pregnancy rate per effective donor recruited (n = 104), defined as the number of women with a clinical pregnancy, per number of women who initiated treatment with a donor's spermatozoa, was 68.5 (± 24.9) %. This measure did not show a significant change in function of year of donation. DISCUSSION: Candidate sperm donors represent a select group of men; as such, these results are not to be interpreted as representative for the general population. CONCLUSION: The study did not show a significant change in sperm concentration or fertility potential in sperm donors over a period of 23 years. However, a negative trend was found for TSC from 2010 onwards. Also, the results show a significant decrease in ideal morphology over time.

SARS-CoV-2 infection, male fertility and sperm cryopreservation: a position statement of the Italian Society of Andrology and Sexual Medicine (SIAMS) (Società Italiana di Andrologia e Medicina della Sessualità).

PURPOSE: The recent pandemic of severe acute respiratory syndrome (SARS) due to coronavirus (CoV) 2 (SARS-CoV-2) has raised several concerns in reproductive medicine. The aim of this review is to summarize available evidence providing an official position statement of the Italian Society of Andrology and Sexual Medicine (SIAMS) METHODS: A comprehensive Pubmed, Web of Science, Embase, Medline and Cochrane library search was performed. Due to the limited evidence and the lack of studies, it was not possible to formulate recommendations according to the Oxford 2011 Levels of Evidence criteria. RESULTS: Several molecular characteristics of the SARS-CoV-2 can justify the presence of virus within the testis and possible alterations of spermatogenesis and endocrine function. Orchitis has been reported as a possible complication of SARS-CoV infection, but similar findings have not been reported for SARS-CoV-2. Alternatively, the orchitis could be the result of a vasculitis as COVID-19 has been associated with abnormalities in coagulation and the segmental vascularization of the testis could account for an orchitis-like syndrome. Finally, available data do not support the presence of SARS-CoV-2 in plasma seminal fluid of infected subjects. CONCLUSION: Data derived from other SARS-CoV infections suggest that in patients recovered from COVID-19, especially for those in reproductive age, andrological consultation and evaluation of gonadal function including semen analysis should be suggested. Studies in larger cohorts of currently infected subjects are warranted to confirm (or exclude) the presence of risks for male gametes that are destined either for cryopreservation in liquid nitrogen or for assisted reproduction techniques.

Selecting the most competent sperm for assisted reproductive technologies.

This paper discusses the variety of effective sperm selection techniques that have been developed for use in assisted reproductive technologies. Available methods for isolating the competent sperm in an ejaculate are outlined, as well as techniques for selecting single sperm for use in intracytoplasmic sperm injection procedures. Case-specific methods for selecting the most competent sperm are discussed, with reference to the potential causes of male factor infertility and guidance for the embryologist based on the issues present for each couple seeking treatment.

Introduction: Male fertility testing: the past, present, and future.

Semen analysis remains the initial laboratory evaluation for infertile men. The limitations of the standard semen analysis along with past attempts to improve the analysis of sperm are reviewed. Advances in genetic testing will lead to fewer diagnoses of idiopathic male infertility, and improvements in picking the best sperm offer hope of improved assisted reproduction outcomes. The development of simplified testing has opened up the availability of tests performed in settings without advanced laboratory facilities as well as by patients in their own homes.

Limits of current male fertility testing.

In the current approach to male fertility testing, basic semen analysis has limitations as a predictor of fertility status, and the technology is fraught with variability. Nonetheless, it remains the cornerstone of the evaluation of the male infertility, and we recommend adherence to most recent World Health Organization guidelines. Although the current sperm function tests (bioassays) have important drawbacks, they are still valuable as research tools. Sperm quality assays with analysis of sperm DNA fragmentation need further investigation before they can be recommended for routine clinical use. The answer to the many current challenging questions relies on identifying spermatogenesis pathologies and the resulting sperm dysfunctions at the cellular and molecular levels. New discoveries may bring answers or new avenues to explore.

Home testing for male factor infertility: a review of current options.

Male factor infertility contributes to about 50% of the incidence of infertility in couples. Semen analysis is key to the diagnosis of the reproductive potential of a male subject. In current practice, men must attend a clinic or other hospital facility to have their semen analyzed. However, many men are not comfortable with this process, which they often find embarrassing and expensive. To solve these problems, many devices for home analysis of semen samples have been developed and commercialized. This review examines the literature pertaining to the currently available home semen test devices and describes their limitations and future directions.

Sperm selection methods in the 21st century.

Natural sperm selection in humans is a rigorous process resulting in the highest quality sperm reaching, and having an opportunity to fertilize, the oocyte. Relative to other mammalian species, the human ejaculate consists of a heterogeneous pool of sperm, varying in characteristics such as shape, size, and motility. Semen preparation in assisted reproductive technologies (ART) has long been performed using either a simple swim-up method or density gradients. Both methodologies provide highly motile sperm populations; however neither replicates the complex selection processes seen in nature. A number of methods have now been developed to mimic some of the natural selection processes that exist in the female reproductive tract. These methods attempt to select a better individual, or population of, spermatozoa when compared to classical methods of preparation. Of the approaches already tested, platforms based upon sperm membrane markers, such as hyaluronan or annexin V, have been used to either select or deselect sperm with varied success. One technology that utilizes the size, motility, and other characteristics of sperm to improve both semen analysis and sperm selection is microfluidics. Here, we sought to review the efficacy of both available and emerging techniques that aim to improve the quality of the sperm pool available for use in ART.

Original investigations into the clearance of spermatozoa after vasectomy.

"The urologist and patient, with the cooperation of the laboratory performing the sperm counts, can determine within a few days after operation that aspermia has been produced and that the procedure has been successful." -Freund M, Davis JE. Disappearance rate of spermatozoa from the ejaculate following vasectomy. Fertil Steril 1969;20:163-70.

Adverse Effects of Cannabis on Male Reproduction.

The use of cannabis use is likely to increase as regulations on its consumption are diminishing throughout the world. Coinciding with an increase in the use of cannabis is an observation that semen quality appears to be declining in developed countries, and couples are delaying conception more often than previous generations. Therefore, it is important to study the effects of cannabis on male reproductive potential in order to better counsel infertile couples and men of reproductive age. In this mini-review, we highlight the known effects of cannabis on clinical markers of male fertility potential and review the role of the endocannabinoid system as it pertains to sex hormone and sperm production, as well as sperm function. Overall, current evidence is contradictory regarding the effects of cannabis on male reproductive hormone production. However, most studies associate cannabis use with lower sperm concentrations, suggesting a negative impact on fertility potential.

Sperm cryopreservation of transgender individuals: trends and findings in the past decade.

OBJECTIVES: Awareness and acceptance of transgenderism have increased in the last two decades. There is limited literature regarding the incidence and semen characteristics of transwomen banking spermatozoa. We sought to assess the incidence of sperm cryopreservation of transgender individuals compared with the cisgender population in the last 10 years. Semen parameters were also compared between the two groups. MATERIALS AND METHODS: We performed a retrospective analysis of sperm cryopreservation performed at a single center from 2006 through 2016. Using available data on indications for banking and prior hormonal therapy status, we isolated healthy transgender and cisgender cohorts for semen parameter comparison. Linear regression was used to compare the incidence trends. Semen parameters were compared using the generalized estimating equations method. The rates of semen parameter abnormality of each group were compared using chi-square test. Semen parameter abnormalities were defined using WHO 2010 reference values. RESULTS: We analyzed 194 transgender samples and 2327 cisgender samples for a total of 84 unique transgender sperm bankers and 1398 unique cisgender sperm bankers. The number of transgender sperm bankers increased relative to cisgender sperm bankers from 2006 to 2016. Following exclusion of cisgender sperm bankers with health issues that might impact semen quality and transgender sperm bankers with known prior hormonal therapy, we compared the semen parameters of 141 healthy cisgender sperm bankers and 78 healthy transgender sperm bankers. The transgender sperm bankers demonstrated lower sperm concentration, total motile sperm count, and post-thaw sperm parameters. The transgender sperm bankers also demonstrated a higher incidence of oligozoospermia. CONCLUSIONS: This is the largest report to date on the incidence of transgender sperm cryopreservation and comparison of semen characteristics with cisgender sperm bankers. The data reveal an increased incidence of transgender sperm banking as well as poorer semen parameters of transgender individuals compared with cisgender controls.

CASA: tracking the past and plotting the future.

The human semen sample carries a wealth of information of varying degrees of accessibility ranging from the traditional visual measures of count and motility to those that need a more computational approach, such as tracking the flagellar waveform. Although computer-aided sperm analysis (CASA) options are becoming more widespread, the gold standard for clinical semen analysis requires trained laboratory staff. In this review we characterise the key attitudes towards the use of CASA and set out areas in which CASA should, and should not, be used and improved. We provide an overview of the current CASA landscape, discussing clinical uses as well as potential areas for the clinical translation of existing research technologies. Finally, we discuss where we see potential for the future of CASA, and how the integration of mathematical modelling and new technologies, such as automated flagellar tracking, may open new doors in clinical semen analysis.