Abstract
BackgroundSince the first report of a decline in semen quality in 1974, there have been several reports of similar declines across populations. Despite some scattered reports of declining semen quality in the Indian sub-continent, comprehensive studies analyzing semen quality over the last few decades have not been undertaken. We undertook the present study to investigate the temporal trend in semen parameters in Indian populations over a period of 37 years (1979–2016).MethodsPublications providing semen analysis details for fertile and infertile men from the Indian sub-continent were collected by a thorough literature search. Semen quality data for 6466 normal fertile or presumptive normal men (from 119 studies/data sets) and 7020 infertile men (from 63 studies/data sets) published between 1979 and 2016 were retrieved. We undertook systematic review and quantitative analysis of mean sperm count, motility, normal morphology and other available parameters. Data were analyzed to estimate semen parameters reference values for Indian men and to assess temporal trends in infertile, fertile and all subjects.ResultsSeminal quality shows a decreasing temporal trend and the decrease is higher in infertile than fertile males. In pooled analysis for all individuals, significant (p < 0.05 or < 0.001) declines in sperm concentration and normal morphology are observed; however, isolated analysis for each group shows declines without statistical significance. The mean (± SD) semen volume, sperm concentration, total motility, rapid linear progressive motility, normal sperm morphology and sperm viability for Indian fertile men are 2.88 ± 0.77 ml, 81.08 ± 29.21 million/ml, 66.37 ± 10.95%, 52.64 ± 15.78%, 56.68 ± 20.23% and 72.63 ± 8.31%, respectively, whereas in infertile these are 3.07 ± 1.27 ml, 37.94 ± 26.41 million/ml, 40.22 ± 13.76%, 26.79 ± 15.47%, 36.41 ± 21.66% and 55.25 ± 11.99%, respectively. The mean seminal parameter values were significantly lower (p < 0.001) in infertile as compared to fertile men, except semen volume.ConclusionsSemen parameters in Indian men have declined with time and the deterioration is quantitatively higher in the infertile group. The study also provides reference values for semen parameters in Indian men.
Highlights
Since the first report of a decline in semen quality in 1974, there have been several reports of similar declines across populations
The effect of decline in semen quality can be understood more clearly from a decline in fertility rate seen in a number of populations
Relevant studies were gathered by computerized search on MEDLINE, GoogleScholar, ResearchGate and Scopus databases, using search terms such as sperm density, sperm morphology, sperm concentration, sperm motility, sperm count, male fertility and semen analysis
Summary
Since the first report of a decline in semen quality in 1974, there have been several reports of similar declines across populations. A threat to sperm production would be Mishra et al Reproductive Biology and Endocrinology (2018) 16:103 clinicians all around the world conducted many retrospective and prospective studies to investigate such changes in the male population of their respective regions and many of them found conceivable downward trend in various semen parameters [4,5,6,7,8,9,10,11,12,13,14,15,16,17,18]. The effect of decline in semen quality can be understood more clearly from a decline in fertility rate seen in a number of populations. With a decline in semen quality, there has been an increase in the demand for assisted reproductive techniques. In India, the number of IVF cycles increased at a rate of 18% and is expected to rise upto 20% by the year 2020 [28]
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