Infertility and problems of impaired fecundity have been a concern through ages and is also a significant clinical problem today, which affects 8-12% of couples worldwide. Of all infertility cases, approximately 40-50% is due to "male factor" infertility and as many as 2% of all men will exhibit suboptimal sperm parameters. It may be one or a combination of low sperm concentration, poor sperm motility, or abnormal morphology. The rates of infertility in less industrialized nations are markedly higher and infectious diseases are responsible for a greater proportion of infertility. The present literature will help in knowing the trends of male factor infertility in developing nations like India and to find out in future, various factors that may be responsible for male infertility.

Trends of male factor infertility, an important cause of infertility: A review of literature.

Consistent age-dependent declines in human semen quality: A systematic review and meta-analysis

Phthalate exposure and male infertility

Reports regarding the changes in sperm concentration in different counties of the world are inconsistent. Furthermore, the reports that sprung up from specific epidemiological and experimental examinations did not include data of prior studies or geographical variations. The current study, following a previous report of massive fall in semen volume over the past 33 years, attempts to delineate the trend of altering sperm concentrations and factors responsible for this by reviewing article published from 1980 to July 2015 with geographic differences. The current study identified an overall 57% diminution in mean sperm concentration over the past 35 years ( r = -.313, p = .0002), which, when analyzed for each geographical region, identified a significant decline in North America, Europe, Asia, and Africa. An increasing trend of sperm concentration was identified only in Australia. The association of male age with such a trend ( R2 = .979) is reported. The authors also correlated male fertility with sperm concentration. Thus, this comprehensive, evidence-based literature review aims to concisely and systematically present the available data on sperm concentration from 1980 to 2015, as well as to statistically analyze the same and correlate male health with the declining pattern of sperm count in a single scientific review to serve the scientific research zone related to reproductive health. It points to the threat of male infertility in times ahead.

https://journals.sagepub.com/doi/pdf/10.1177/1557988316643383

The Disappearing Sperms: Analysis of Reports Published Between 1980 and 2015.

Although semen quality is an important determinant of fertility, defining clear thresholds for normal ranges has proven difficult. According to 'time to pregnancy' studies, fecundity starts to decline when sperm concentrations fall below 30-55 × 106/ml, whereas the WHO criterion for normal values is currently 15 × 106/ml. Multiple studies over the past 15 years have reported median sperm concentrations of 41-55 × 106/ml in young men (mean age 18-21 years) from the general population, suggesting that many of them have suboptimal semen quality. Sperm numbers remain fairly constant between 19 and 29 years of age, which points to the importance of developmental effects. Discussion on whether population semen quality has declined has continued for decades, as regional differences in trends have been noted. The reasons for poor semen quality and adverse trends are not well established, but some associations suggest a causal relationship, for example, with maternal smoking during pregnancy. The role of chemical exposures leading to endocrine disruption and detrimental reproductive effects has been in the focus of research during the past 20 years. Identification of exposures that affect fertility could provide opportunities for effective prevention of reproductive health problems.

Semen quality in the 21st century.

The data on semen analysis of subjects attending the Fertility Clinic at NIHFW (National Institute of Health and Family Welfare) Munirka New Delhi for the last 11 years were analyzed to verify the claims and speculations on declining sperm counts in men. Approximately 10 % of the records every year starting from 1990 to 2000 (numbering 1176 in total) were randomly selected for analysis. Subjects with azoospermia or severe oligozoospermia were excluded from analysis. The average age of the men attending the infertility clinic was 31.2 years. The average semen volume and sperm count were found to be (2.6±0.1) mL and (60.6±0.9) ×106/mL respectively. No significant decline in sperm counts was observed in any year during the entire study period. Only 1.8 % of the total number of sperm counts in the random sampling were less then 20×106/mL. On the basis of WHO criteria on motility the total percentage of non-progressive and non-motile sperm in the ejaculate was higher (63 %) as compared to the combined categories of slow and rapid linear progressive. The present study has confirmed similar findings from other different countries that declining sperm counts in humans is not a global phenomenon. (authors)

Misro Mm

Papers

Evaluation of trend in semen analysis for 11 years in subjects attending a fertility clinic in India.