December 9, 2024
The short answer: it depends, but, mostly, yes they can.
The long answer: it’s a bit more complicated.
For almost half a century the medical community has debated whether varicoceles can cause infertility. The amount of research and literary review on the subject is by no means limited, but issues with participant selection, examiner bias, and other fertility factors all lead to many inconclusive results.
Despite this, there is enough evidence to help you get a better understanding of the role varicoceles can play in male infertility. We’ve looked through the research so you don’t have to, and this is what we’ve found.
What is a Varicocele?
A varicocele is a collection of swollen veins in the scrotum.
Varicoceles occur because of a problem with the valves in the veins which carry blood from the scrotum and testicles.
A spermatic cord, within the pampiniform plexus, holds up each testicle, and this cord contains the veins, arteries, and nerves that support the testicles. In healthy veins, one-way valves move the blood from the testicles back to the heart.
When "leaky", these valves do not return the blood back to the heart as they should and this causes a buildup of pressure, and therefore swollen veins, and a varicocele develops slowly over time.
Suggested Reading: The 5 Must-Know Signs and Symptoms of Varicocele
Do Varicoceles Lead to Infertility?
Let’s take a quick look at what the research says about the relationship:
- An estimated 10% to 20% of men diagnosed with a varicocele will experience problems fathering a child.
- Amongst men diagnosed as infertile (for other various reasons), 40% have a varicocele
- The most common cause of male infertility (the male factor is involved in 40% to 50% of infertility cases) is idiopathic infertility, which is characterised by one or more abnormal semen parameters.
So what do these statistics mean? Put simply, varicoceles can cause infertility in 10% to 20% of men, but for men experiencing infertility due to issues such as sperm count and quality, around 40% of these also have a varicocele.
So in essence, there are multiple factors to consider when trying to determine if a link exists between having a varicocele and having issues with spontaneous pregnancy, and for most men having a varicocele will not cause infertility and it is usually caused by another issue. But the fact that varicoceles are prevalent in men who are infertile cannot easily be dismissed.
Problems in Establishing a Link #1: Varicocele Prevalence
The question of whether a varicocele can cause infertility amongst men has been debated for almost 50 years, and even amongst professionals who spend their time researching the condition and academics who review and critique the literature, there is a difference of opinion.
One of the major issues surrounding the clear establishment of a link between varicoceles and infertility is the accurate reporting of varicoceles within both fertile and infertile men.
One study noted that the prevalence of varicoceles varies greatly, depending on what studies you look at. It’s commonly accepted that varicoceles occur in 15% of men, but studies place this number anywhere from 4% to 30%. When looking at infertile men the rates vary from 17% to 41%.
To add another layer to this complexity, the World Health Organisation published a 1992 study where, dependent on geographical location, the frequency of varicoceles in infertile men ranged from 6% to 47%
Problems in Establishing a Link #2: Examiner Bias
Much of the research surrounding the link between varicoceles and infertility is influenced by some form of examiner bias. This means that the doctor diagnosing the varicocele in the first place plays an important role in establishing such a link.
Take for instance a study published in 1991 that involved two researchers examining the same group of 138 patients independent of each other. The first researcher diagnosed varicoceles in 31% of men, while the second researcher only diagnosed 19%.
If the same group of men can receive different diagnosis rates, how can we reliably establish a link between varicoceles and infertility?
Varicocele and Semen Parameters
When it comes to fertility, there are multiple factors that a fertility expert will look at the consider your sperm count and health, and there is debate amongst academics and professionals as to whether varicoceles can influence these factors.
Semen analysis considers the following semen parameters:
- number of sperm (sperm count)
- shape of sperm (sperm morphology)
- movement of sperm (sperm motility)
One study found that infertile men with a varicocele had significantly lower semen parameters than men who were fertile, suggesting that varicocele presence can play a part in reducing sperm quality and count. However, one criticism of this study was that the sample size was small and may have affected the validity and real-world applicability of the results.
A second study found, however, that there is no significant difference in semen parameters between infertile men of the general population with or without varicocele.
Thus, it is speculated that the presence of a varicocele can affect fertility and sperm quality in some, but not all, men. Further. it is assumed that sperm quality is not directly influenced by varicocele presence and that they simply coexist in men with idiopathic (no discernible cause) infertility.
Varicocele Treatment and Improved Fertility
For most men seeking an answer to the question “do varicoceles cause infertility”, the next question becomes “can treatment improve fertility", or "can a man with a varicocele get a woman pregnant?"
The short answer is yes, repairing a varicocele may improve fertility and help a couple get pregnant, but there are many studies that have found no significant improvement in fertility or the incidence of pregnancy as a result of treating a varicocele.
However, many of these studies considered varicocelectomy, and at Northern Beaches Interventional Radiology we offer patients varicocele embolisation, which has been shown to have different treatment outcomes.
Varicocele embolisation is a minimally invasive treatment option that uses special ‘blocking agents’ to block blood flow to the testicles, which can reduce varicoceles over a period of days or weeks.
One study found that varicocele embolisation, performed in men with a clinically visible left varicocele, resulted in significant improvement in semen parameters.
Other literature places the success rate between 30% and 35% for couples undergoing varicocele embolisation who also have no female infertility factors.
What has been noted by multiple studies is that, even in cases where varicocele embolisation does not improve the rate of spontaneous pregnancy, having the procedure can improve semen parameters enough for assisted fertility procedures such as IVF.
In Summary
While the debate rages on, there is sufficient evidence to suggest that varicoceles can cause infertility over time, but only in a small number of men. Most men who have a varicocele do not experience any fertility problems.
The exact cause of the infertility isn’t known, and in most cases where a man is infertile he will also have a varicocele. This has led researchers to surmise that varicoceles may impact sperm quality, which influences fertility. However, in most cases varicoceles simply coexist with low semen parameters and have no direct impact.
When it comes to treating a varicocele, varicocele embolisation has been shown to provide a boost to fertility but the circumstances under which this is the case is limited to couples with no female infertility factors.
For some men, treatment can improve the chances of spontaneous, unassisted pregnancy, and there is reliable data to suggest a positive link between varicocele embolisation and increased chances of pregnancy through assisted fertility procedures.
