A recent study published in the journal Scientific Reports has shown a decrease in the quality of sperm in men from Nigeria and South Africa. The study, titled “Trends in semen parameters of infertile men in South Africa and Nigeria,” is the first to examine temporal trends in semen parameters in Sub-Saharan Africa.
The findings show an “alarming decreasing trend in semen parameters in Nigeria and South Africa from 2010 to 2019,” with asthenozoospermia and teratozoospermia being the leading causes of male infertility in these regions. The study is a retrospective analysis of semen analyses of 17,292 men attending fertility hospitals in Nigeria and South Africa in 2010, 2015, and 2019.
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The variables assessed included ejaculate volume, sperm concentration, progressive motility, total progressively motile sperm count (TPMSC), total sperm count, and normal sperm morphology.
The study found that normal sperm morphology and ejaculatory volume had significantly decreased between 2010 and 2019, indicating a progressive deterioration of the values in both countries. In Nigeria, there were significant decreases in progressive motility, TPMSC, and sperm morphology between 2010 and 2019.
Spearman’s rank correlation revealed significant negative associations between age and morphology, progressive motility, and TPMSC. Patients in South Africa were younger than those from Nigeria, with also a significantly higher sperm morphology, sperm concentration, progressive motility, total sperm count, and TPMSC.
Semen parameters including sperm concentration, total sperm count, sperm motility, TPMSC, sperm morphology, and semen volume are essential diagnostic tools for assessing the reproductive health and fertility status of men. Several studies have shown a decline in sperm concentration and quality in western countries including the United States, Australia, and Europe since the late 1930s.
A decline in sperm motility, sperm count, and morphology has also been reported among Indian men. Similarly, significant declines in sperm concentration and total sperm count have been reported among Chinese men within four decades. A 23-year (1995–2018) study in Brazil also reported a decline in sperm parameters.
Researchers led by Professor Oladapo Adenrele Ashiru, joint pioneer of In Vitro Fertilisation (IVF) in Nigeria and President, African Fertility Society (AFS), have expressed concern over the decline in semen parameters and have called for a thorough investigation on the underlying factors promoting this worrisome decline.
Aberrations in sperm parameters remain the leading cause of male factor infertility. The findings of this study could be a valuable tool for policymakers and healthcare practitioners in addressing infertility issues in Nigeria and South Africa.