BACKGROUND: Infertility is a burdensome, often overlooked condition. This study aimed to investigate the global distribution and trends in the burden of infertility from 1990 to 2021. METHODS: We obtained data on the prevalence and years lived with disability (YLDs) related to infertility from the Global Burden of Disease 2021 study and evaluated them by calculating the estimated annual percentage change in age-standardized rates. We investigated the relationship between sociodemographic index (SDI) and the burden of infertility on the global, regional, and national levels. RESULTS: In 2021, there were 143,261,562 female and 55,481,380 male infertility cases worldwide, respectively. In China, female and male infertility cases accounted for 23.59% and 21.47% of the global totals, reaching 33,795,944 and 11,909,889, respectively. Compared with 2019, the global number of female and male infertility cases increased by 5,286,227 in females and 2,017,271 in males. In contrast, China saw a decline in both female and male infertility cases, with reductions of 698,735 and 154,591, respectively. From 1990 to 2021, the age-standardized prevalence rate (ASPR) and age-standardized YLDs rate (ASYR) for female infertility both increased by 0.59% annually, whereas these two corresponding indicators for male infertility increased by 0.50% annually worldwide. The burden of female infertility was consistently higher than that of male infertility and demonstrated a faster rate of increase. East Asia had the highest ASPR and ASYR for female infertility, whereas Eastern Europe had the highest metrics for male infertility. A horizontal S-shaped association was observed between the SDI and ASPR and ASYR of infertility, with a rapid decline in the infertility burden when the SDI exceeded 0.7. CONCLUSIONS The global burden of infertility has increased over the years, with a higher burden on women and underdeveloped regions. These findings emphasize the need to prioritize healthcare for patients with infertility to address the rising burden.
Humans ; Female ; Male ; Global Burden of Disease ; Prevalence ; Infertility/epidemiology* ; Adult ; Infertility, Male/epidemiology* ; Persons with Disabilities/statistics & numerical data* ; Middle Aged ; Infertility, Female/epidemiology* ; China/epidemiology* ; Disability-Adjusted Life Years

Recently, male reproductive health has attracted extensive attention, with the adverse effects of circadian disruption on male fertility gradually gaining recognition. However, the mechanism by which circadian disruption leads to damage to male reproductive system remains unclear. In this review, we first summarized the dual regulatory roles of circadian clock genes on the male reproductive system: (1) circadian regulation of testosterone synthesis via the hypothalamic-pituitary-testicular (HPT) and hypothalamic-pituitary-adrenal (HPA) axes; (2) non-circadian regulation of spermatogenesis. Next, we further listed the possible mechanisms by which circadian disruption impairs male fertility, including interference with the oscillatory function of the reproductive system, i.e., synchronization of the HPT axis, crosstalk between the HPT axis and the HPA axis, as well as direct damage to germ cells by disturbing the non-oscillatory function of the reproductive system. Future research using spatiotemporal omics, epigenomic assays, and neural circuit mapping in studying the male reproductive system may provide new clues to systematically unravel the mechanisms by which circadian disruption affects male reproductive system through circadian clock genes.
Male ; Humans ; Animals ; Circadian Clocks/physiology* ; Hypothalamo-Hypophyseal System/physiology* ; Circadian Rhythm/genetics* ; Spermatogenesis/physiology* ; Pituitary-Adrenal System/physiology* ; Testis/physiology* ; Testosterone/biosynthesis* ; CLOCK Proteins ; Infertility, Male/physiopathology*

Testicular tumor is the most common solid malignancy in males under 40 years of age. This malignancy is known to have a negative impact on male fertility. Therefore, several techniques for sperm retrieval have been proposed, including microdissection testicular sperm extraction (mTESE). The objective of this study was to review the literature on the outcomes of oncological (Onco)-mTESE at the time of radical orchiectomy. We conducted a comprehensive literature search through PubMed, Scopus, and Cochrane Central Controlled Register of Trials. Only studies reporting ex vivo mTESE in patients with testicular tumor were considered. Twelve papers met the inclusion criteria and were included in this review. Tumor size was identified as the sole preoperative factor influencing spermatogenesis. The considered studies demonstrated a satisfactory success rate for Onco-mTESE, associated with a similarly valid percentage of live healthy births through assisted reproductive technology. Currently, no comparison has been made between Onco-mTESE and conventional Onco-TESE, hence further assessment is required. In cases where the tumor completely replaces the cancer-bearing testicle, a contralateral micro-TESE may be a viable alternative. However, the surgeon should evaluate associated risks and benefits preoperatively. In conclusion, Onco-mTESE at the time of radical orchiectomy appears to be a promising therapeutic option for young patients with testicular tumors. Nevertheless, additional studies are necessary to achieve a definitive conclusion.
Humans ; Male ; Azoospermia/etiology* ; Sperm Retrieval ; Orchiectomy/methods* ; Testicular Neoplasms/complications* ; Microdissection/methods* ; Testis/surgery* ; Adult

Discovery of spermatozoa during the 17 th century led to developing technologies for semen analysis in the early 1900s, and then, standard techniques were implemented during the 20 th century. Semen analysis has a pivotal role in the male infertility evaluation, and azoospermia is an important finding. Azoospermia is identified in 15% of infertile men. However, the accurate laboratory assessment of azoospermia poses certain technical challenges. Laboratories currently perform semen assessment with great variability; thus, a standard method should be used. Planning suitable management and determining the cause of infertility require a precise evaluation of azoospermia. This review aims to address the definition of azoospermia and highlight laboratory methods in the assessments of azoospermia. Basic methods such as centrifugation, repeat pellet analysis, and staining and advanced methods such as genetic testing and biomarkers have been discussed. These methods have helped in standardizing the protocol for accurate azoospermia assessments with less variability.
Humans ; Azoospermia/genetics* ; Male ; Semen Analysis/methods* ; Andrology/methods*

When microdissection testicular sperm extraction (micro-TESE) fails, a redo procedure may be the only option for patients who want a biological child. However, there are many gaps of knowledge surrounding the procedure, which need to be addressed to help clinicians and patients make informed decisions. This review explores redo micro-TESE in the context of nonobstructive azoospermia (NOA). Literature was searched using Google Scholar, Medline, and PubMed. Search terms were "NOA" AND "second microdissection testicular sperm extractions" AND "redo microdissection testicles sperm extraction" AND "repeat microdissection testicular sperm extractions" AND "failed microdissection testicular sperm extractions" AND "salvage microdissection testicular sperm extractions". Only original articles in English were included. A total of nine articles were included, consisting of four retrospective and five prospective studies. The time gap between the first and second micro-TESE varied from 6 months to 24 months. Most of the included studies reported successful surgical sperm retrieval (SSR) in the second micro-TESE in the range of 10%-21%, except in one study where it reached 42%. It has not been presented any definitive information about the use of hormonal treatment or the benefit of varicocelectomy prior to the second micro-TESE. Patients with hypospermatogenesis and Klinefelter syndrome (KS) had the highest chance of success in redo surgery. In conclusion, redo micro-TESE following a negative procedure can lead to sperm recovery in 10%-21%. Patients with hypospermatogenesis and KS have a higher chance of success. There is no enough evidence to conclude which is the best hormonal stimulation if any before a redo surgery.
Humans ; Male ; Azoospermia/surgery* ; Sperm Retrieval ; Microdissection ; Reoperation ; Treatment Failure ; Testis/surgery* ; Treatment Outcome

Nonobstructive azoospermia (NOA) is the most challenging and complex clinical scenario for infertile men. Besides circumstances such as hypogonadotropic hypogonadism, surgical sperm retrieval is typically necessary, and microdissection testicular sperm extraction (micro-TESE) is the procedure of choice for men with NOA desiring to father children with their own gametes. Micro-TESE results in the highest numbers of sperm cells retrieved for use with in vitro fertilization/intracytoplasmic sperm injection (ICSI) in comparison to all other techniques for surgical sperm retrieval in men with NOA. Several factors may affect sperm retrieval rate and ICSI outcomes, including the patient's age, testicular volume, histopathological and genetic profile, and serum hormone levels. This article aims to review the medical literature describing predictors of successful micro-TESE and the outcomes of ICSI in men with NOA.
Humans ; Azoospermia/surgery* ; Male ; Sperm Injections, Intracytoplasmic ; Sperm Retrieval ; Treatment Outcome ; Testis/pathology* ; Female ; Microdissection

One major challenge in male factor infertility is nonobstructive azoospermia (NOA), which is characterized by spermatozoa-deficient semen without physical duct blockage. This review offers a thorough overview of the histopathology of the testes in NOA cases, clarifying its complex etiology and emphasizing the possible value of histopathology inspection for both diagnosis and treatment. Variable histopathological findings have been linked to NOA, such as tubular hyalinization, Sertoli cell-only syndrome, hypospermatogenesis, and germ cell arrest. Understanding the pathophysiology and forecasting the effectiveness of treatment are further enhanced by both morphometric and ultrastructural analyses. The potential significance of testicular biopsy in forecasting reproductive outcomes is assessed, especially concerning assisted reproductive technologies like intracytoplasmic sperm injection (ICSI). Besides, testicular microlithiasis, serum hormone profiles, and testicular size are investigated concerning NOA histopathology. It is concluded that understanding the histopathological patterns in NOA is crucial for its accurate diagnosis and appropriate management. Further research is still warranted to improve understanding of the complex pathophysiology underlying NOA.
Humans ; Azoospermia/etiology* ; Male ; Testis/pathology* ; Sertoli Cell-Only Syndrome/pathology* ; Sperm Injections, Intracytoplasmic

Approximately 15% of men in the general population have varicoceles, and varicoceles are diagnosed in 40% of men presenting for fertility evaluations. One percent of men in the general population are azoospermic, and 15% of men presenting for fertility evaluations are diagnosed with azoospermia. This article aims to review the impact of varicoceles on testicular function in men with azoospermia, the impact of varicocele repair on the semen parameters of azoospermic men, and the impact of varicocele repair on sperm retrieval and pregnancy outcomes when the male partner remains azoospermic after varicocele repair.
Humans ; Varicocele/physiopathology* ; Azoospermia/physiopathology* ; Male ; Pregnancy ; Female ; Sperm Retrieval ; Semen Analysis ; Pregnancy Outcome ; Testis/physiopathology*

Varicocele is a prevalent condition in the infertile male population. However, to date, which patients may benefit most from varicocele repair is still a matter of debate. The purpose of this study was to evaluate whether certain preintervention sperm parameters are predictive of successful varicocele repair, defined as an improvement in total motile sperm count (TMSC). We performed a retrospective study on 111 patients with varicocele who had undergone varicocele repair, collected from the Department of Endocrinology, Metabolic Diseases and Nutrition, University of Catania (Catania, Italy), and the Unit of Urology at the Selcuk University School of Medicine (Konya, Türkiye). The predictive analysis was conducted through the use of the Brain Project, an innovative tool that allows a complete and totally unbiased search of mathematical expressions that relate the object of study to the various parameters available. Varicocele repair was considered successful when TMSC increased by at least 50% of the preintervention value. For patients with preintervention TMSC below 5 × 10 6 , improvement was considered clinically relevant when the increase exceeded 50% and the absolute TMSC value was >5 × 10 6 . From the preintervention TMSC alone, we found a model that predicts patients who appear to benefit little from varicocele repair with a sensitivity of 50.0% and a specificity of 81.8%. Varicocele grade and serum follicle-stimulating hormone (FSH) levels did not play a predictive role, but it should be noted that all patients enrolled in this study were selected with intermediate- or high-grade varicocele and normal FSH levels. In conclusion, preintervention TMSC is predictive of the success of varicocele repair in terms of TMSC improvement in patients with intermediate- or high-grade varicoceles and normal FSH levels.
Humans ; Varicocele/complications* ; Male ; Retrospective Studies ; Machine Learning ; Adult ; Treatment Outcome ; Sperm Count ; Infertility, Male/etiology* ; Sperm Motility ; Follicle Stimulating Hormone/blood* ; Young Adult

Nonobstructive azoospermia (NOA) is considered the most challenging clinical scenario for infertile men and current treatments leave many men unsuccessful at being able to achieve a pregnancy with their partner using their own sperm. Microdissection testicular sperm extraction (micro-TESE) is the choice for men with NOA desiring to father children with their own gametes. Micro-TESE results in the highest numbers of sperm cells retrieved for use with in vitro fertilization/intracytoplasmic sperm injection. With suboptimal micro-TESE success rates of sperm retrieval and then pregnancy and live birth using the retrieved sperm with in vitro fertilization/intracytoplasmic sperm injection, advances to improve outcomes are necessary. This article comprehensively reviews the technologies investigated to date to improve the outcomes for men undergoing micro-TESE.
Humans ; Male ; Sperm Retrieval ; Azoospermia/surgery* ; Pregnancy ; Female ; Sperm Injections, Intracytoplasmic ; Microdissection/methods* ; Fertilization in Vitro ; Testis/surgery*