Many fertility tests and treatments focus on the female partner, but a recent study has shown that male fertility in the west is in a state of crisis. A meta-analysis of sperm counts in men across a number of western countries, including North America, Australia, New Zealand, and Europe showed a decline of over 50% over the last 40 years.
A study in Human Reproduction Update shows not only that the decline is substantial, but that it is showing no signs of levelling off. While numerous studies have shown a drop in sperm count across general populations this is a significant meta-analysis of the subject, which included 7,500 other studies. It is more respected because it addressed two of the potential weaknesses in this type of meta-analysis; by excluding studies from populations of men attending fertility clinics, and also studies where the measurement techniques were below a certain standard. It also allowed for factors such as time from last ejaculation and age, all of which suggests that there are environmental factors at play rather than purely lifestyle changes.
The lack of rigorous control from other countries means that it is difficult to say exactly what has caused the drop – whilst the effect is not seen in countries such as Pakistan, there are fewer sperm counts conducted in developing nations so it is difficult to come to a firm conclusion about whether this is isolated to western/developed nations or is a world-wide trend.
Also, it is not the first meta-analysis on the subject. One 25 years ago suggested that sperm counts had halved around the world over the preceding 60 years. And there have been others since, all of which result in the same type of news headlines. There is reason to be sceptical and some experts have advised caution. As well as the two potential weaknesses mentioned above there can be numerous other factors; for example, over the decades methodology for evaluating sperm has improved. If we are better at spotting faulty sperm nowadays it is no wonder that a meta-analysis would reflect this as a decline in quality where none actually exists.
A common solution where there is a male-factor cause of infertility is to use IVF with ICSI. Here at Concept, we find that, over the last two years, the percentage of IVF cycles requiring ICSI has been 31%. Whilst this does not prove anything in itself, it does not indicate that there is currently a major problem. Nevertheless, this most recent meta-analysis does tell us that either there is a long trend problem with male fertility or that we need better information.
Consensus in the scientific community is that if there is a problem, environmental factors must be a root cause, as genetics would not cause such a rapid decline. Further research is required and expected.
What is clear is that it’s important to stop the under-investment in male fertility research and treatment to get to the cause of this and create solutions that will at least prevent sperm counts from dropping further, whether that is the development of treatments to increase sperm count more reliably, or government intervention to curtail the use of harmful chemicals within the environment.
