Male fertility investigations

Nutrition for male fertility oily fish 173657085.jpg

The most useful tool in testing for male infertility is the semen analysis. The ‘normal’ values for different measurements of sperm quality have been worked out by testing large groups of healthy fertile volunteers. When a semen analysis is done, the results are compared with the normal range of values and any abnormalities will suggest a male problem. The tests carried out on a semen sample will look for abnormalities in sperm number (the sperm count), sperm movement and sperm shape.

Blood tests to assess the levels of hormones relevant to sperm production are also used to exclude hormonal factors and/or abnormalities. Also, genetic tests may be required in men who are azoospermic or have very low sperm counts.

Investigations cover:

1 % of men suffer from azoospermia (a condition diagnosed when there is no sperm in the ejaculate) and will require sperm to be surgically retrieved for use in a cycle of ICSI to allow a chance of successful conception. 

Azoospermia can be divided into either "obstructive" or "non-obstructive."

In obstructive azoospermia there is an obstruction as a likely consequence of either an absent or blocked tube connecting the testicle to the penis (vas deferens), for example following a vasectomy or in some men who are carriers of a defective cystic fibrosis gene. In these men there is virtually a 100% chance of successfully finding sperm surgically.

Non-obstructive azoospermia is a more severe form of male infertility but still potentially treatable. It should still be remembered that sperm can still be found in up to 50% of men with non-obstructive azoospermia. Our male fertility team have published extensively in the world literature on this subject see links 1,2,3 below).

All men with azoospermia should undergo a comprehensive history and physical examination to try and find the cause of azoospermia. However, in about 60-70% of cases an underlying cause may not be found.

Investigations will include complex genetic testing including Chromosome testing, Y deletion and cystic fibrosis gene analysis. Other tests will include hormone testing and scans.

Your consultant will discuss your fertility options with you.

Patients of the Lister Fertility Clinic who need surgery will be treated in conjunction with one of our expert male fertility team.

Low sperm counts can be due to a number of causes including; infections, previous surgeries such as torsion undescended testis, varicoceles, hormone problems, drugs and chemotherapy. Depending upon the underlying cause there may be medical or surgical treatments that our team will advise you on.

In about 30% of couples despite full investigation and screening, an underlying cause for male infertility will not be found. However, it is now clear that in many cases the DNA of the sperm may be fragmented.

Our research (see attached paper) has demonstrated that sperm DNA fragmentation may now be an important reason why couples may fail to conceive either naturally, suffer from recurrent pregnancy loss and not be successful from IVF treatments. Our team will evaluate a couple on an individual basis and assess whether SDF testing should be undertaken, evaluate the causes for this and optimise your treatment.

Although both viral infections such as mumps and STI can lead to damage to the testis and blockages of the testis, there is increasing evidence that our own bacteria or male microbiome can cause infertility. Our own research and that of others has demonstrated that genital infections are associated with male infertility and can cause raised SDF. We can offer comprehensive infection screening in men with infertility.

The relationship between genitourinary microorganisms and oxidative stress, sperm DNA fragmentation and semen parameters in infertile men.
Ho CLT, Vaughan-Constable DR, Ramsay J, Jayasena C, Tharakan T, Yap T, Whiteman I, Graham N, Minhas S, Homa ST.Andrologia. 2022 Mar;54(2):e14322. doi: 10.1111/and.14322.

The semen microbiome and its impact on sperm function and male fertility: A systematic review and meta-analysis.
Farahani L, Tharakan T, Yap T, Ramsay JW, Jayasena CN, Minhas S.Andrology. 2021 Jan;9(1):115-144. doi: 10.1111/andr.12886. Epub 2020 Oct 7

It has now become quite clear that it is not just the quality of sperm on standard semen analysis that may predict outcome from treatments such as IVF. Interestingly, up to 30% of men with unexplained infertility may have a raised or damaged sperm DNA. It has been shown that a raised DNA fragmentation may lead to recurrent failure in IVF treatments.

There are a number of causes of raised DNA fragmentation including infections, varicoceles and dietary problems and should be excluded in men and their partners before or after failing IVF treatment. In some cases, it has been proposed that sperm can be harvested directly from the testicle and may have less fragmented DNA compared to ejaculated sperm, which might improve the success rates from ICSI.

Interestingly, there may also be an abnormal complement of chromosomes in the sperm, which can also lead to failure of success of ART. This is called sperm aneuploidy.

Both of these tests are complex tests and are offered by our male fertility experts.

Damage to sperm genetic material (DNA) can occur when sperm are made, breaking or fragmenting the DNA. Men with high sperm DNA damage are less likely to get their partner pregnant and have increased miscarriage risk. Even if your sperm count is normal, the sperm may not be of good DNA fragmentation quality which can reduce the chance of conceiving.

Why should I get tested?

 The COMET test measures sperm DNA damage (fragmentation). Knowing whether you have sperm DNA damage can help you make informed decisions about the type of IVF treatment and lifestyle/health changes to improve your sperm DNA and fertility.

Can I improve my sperm DNA?

 Sperm DNA damage is often associated with underlying medical conditions (such as varicoceles or infection) and some lifestyle choices (such as smoking). Your urologist will discuss steps you can take and the best treatment options when discussing your result.

Are there any risks?

Sperm DNA damage testing is a non-invasive procedure performed on a semen sample. There are no significant additional risks to the patient. It is important to note that whilst there is some evidence for a relationship between sperm DNA damage and fertility treatment outcome, some of this evidence is inconclusive. Please refer to the treatment add-ons page of the HFEA website at

Varicoceles are dilated veins that drain the testicles often referred to as a bag of worms. They are graded I-III depending upon the size of the veins and occur in up to 15% of men but 40% of men with infertility. They can cause a reduction in sperm count and fixing them may improve fertility. More recently it has been suggested that varicoceles may also cause raised sperm DNA fragmentation and fixation may reduce DNA damage.


 Most varicoceles can be diagnosed clinically although USS of the testis is usually performed to confirm the diagnosis by measuring the diameter of the dilated veins and confirming reflux or blood going back onto the testicle.


Varicoceles can be treated by both microsurgery or an interventional radiological procedure called embolization. Our male fertility team will be able to advise you on the best procedure for you.

Testicular Swelling

Lumps or swelling in the testicles (balls) should be checked by a consultant Urologist. Lumps or swelling in the testicles are not usually an indication of anything serious. However, it could be a sign of testicular cancer. This is easy to treat if caught early.

You should always see your consultant if you find:

  • a lump in your testicles
  • a change in the shape, feel or size of your testicles
  • an ache in your testicles that doesn't go away.

Does hormonal therapy improve sperm retrieval rates in men with non-obstructive azoospermia: a systematic review and meta-analysis.
Tharakan T, Corona G, Foran D, Salonia A, Sofikitis N, Giwercman A, Krausz C, Yap T, Jayasena CN, Minhas S.Hum Reprod Update. 2022 May 8:dmac016. doi: 10.1093/humupd/dmac016.

Salvage micro-dissection testicular sperm extraction; outcome in men with non-obstructive azoospermia with previous failed sperm retrievals.
Kalsi JS, Shah P, Thum Y, Muneer A, Ralph DJ, Minhas S.BJU Int. 2015 Sep;116(3):460-5. doi: 10.1111/bju.12932. Epub 2015 Jun 3

In the era of micro-dissection sperm retrieval (m-TESE) is an isolated testicular biopsy necessary in the management of men with non-obstructive azoospermia?
Kalsi J, et al. Among authors: minhas s. BJU Int. 2012. PMID: 21883824

Analysis of the outcome of intracytoplasmic sperm injection using fresh or frozen sperm.
Kalsi J, Thum MY, Muneer A, Pryor J, Abdullah H, Minhas S.BJU Int. 2011 Apr;107(7):1124-8. doi: 10.1111/j.1464-410X.2010.09545.x.