Decreasing male fertility... a myth or a fact?
A fact.
A recent meta-analysis in Human Reproduction showed data and evidence for a consistent decline in Total Sperm Count of 1.6% per year from 1973-2011. In addition, findings from a recent study on European, Australian and North American men between 1973-2011 found a 50-60% decline in Sperm Concentration and Total Sperm Count with no signs of levelling off in recent years.
Because we all love a graph!
This strongly suggests a significant decline in male reproductive health, which has serious implications, even beyond fertility concerns.
The World Health Organisation has even gone so far as to change their recommended 'normal' semen test parameters, reducing sperm concentration from 20 million/ml to 15 million/ml, motility from 50% to 40% and morphology from 30% to 4%.
It is well known that semen quality declines with age although much slower than egg quality does in women. Sperm DNA integrity is also critically important as it transfers half of the necessary chromosomes required for a new human. Think of it as Amazon delivering one half of a sock shipment!
Getting Technical: What is Sperm DNA
Sperm DNA is the genetic material within the sperm. The integrity of this genetic material is crucial for successful fertilisation and normal embryo development.
Sperm DNA fragmentation, i.e fragmented or abnormal material within the sperm can lead to subfertility, IVF failure and miscarriage. Unfortunately, sperm cannot repair its own DNA.
What causes Sperm DNA Fragmentation?
Naturally, sperm DNA fragmentation begins to gradually rise >30 years of age however many other factors can also cause damage. Infection, free radicals, obesity, high fever, elevated testicular temperature (hence the importance of keeping your special bits out of the hot bath), varicocoele, advanced age, poor diet, drug use, cigarette smoking, exposure to environmental and occupational pollutants and increased length of sexual abstinence have all been found to cause sperm DNA fragmentation.
Men can often have normal sperm parameters (count, motility and morphology) but still have an increase in DNA damage. Often times fertilisation of an embryo can occur with damaged sperm, with development continuing until the fragmented area is reached - then development stops. This can result in an arrested embryo (embryo thats stops growing) or an early miscarriage.
Is there any good news?!
Previous studies in 2014 found low quality evidence on the positive affects of antioxidant supplementation and clinical pregnancy rates suggesting no benefit, however more robust research is ongoing.
Preliminary research by Dr. Martin Imhof has shown that supplementation can significantly improve sperm DNA integrity thereby increasing pregnancy rates.
The study took 306 subfertile men. Sperm Chromatin Dispersion (SCD) test was done to detect DNA fragmentation
146 males receives 2 capsules daily of a standardized micronutrient compound (Profertil®, Lenus Pharma, Vienna, Austria)
160 males in control group – did not take the micronutrient supplements and made lifestyle change only (each group was similar in age and BMI).
After 3 months, the SCD test was repeated for both groups.
Findings: The study showed that for men with sperm DNA fragmentation of over 15%, two micronutrient supplements daily for 3 months decreased DNA fragmentation and increased pregnancy rate
This preliminary data is showing that taking micronutrient supplements appears to be superior to lifestyle changes alone.
Overall pregnancy rate after (9 months) for the group taking the supplements was 28.06% and those who made lifestyle changes only was 16.31%.
This is not to undermine the incredible effects of lifestyle changes such as weight loss, quitting smoking, avoiding drugs as these will improve overall health including sperm DNA fragmentation.
Official publication of these findings is pending (Dr. Imhof, Austria) before a real conclusion can be made.
Current European Society for Human Reproduction and Embryology (ESHRE 2017) guidelines recommend sperm DNA fragmentation testing for men whose partners experience recurrent pregnancy loss. It is important to understand how lifestyle can effect sperm and what small changes you can make to improve your fertility potential.
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