Sperm – the other half of the fertility equation

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Sperm contributes half of the genetic material needed for embryos to form. Issues related to sperm quality or function can lead to difficulties in embryo development, including issues with:

  • Genetic material quality: For successful fertilisation and healthy embryo development, ideally sperm DNA should remain intact. Damage to this genetic material – whether from oxidative stress, environmental factors or ageing – can lead to chromosomal abnormalities or improper DNA variations in the embryo, increasing the risk of developmental issues or miscarriage.
  • Sperm chromatin structure: Sperm chromatin, the DNA arranged within the sperm cell, must be tightly packed and properly organised to protect against DNA damage. Normal sperm chromatin structure is needed for successful fertilisation and embryo development. Abnormalities in chromatin structure can result in poor DNA repair, leading to embryo fragmentation (when tiny pieces of the cells that make up the embryo break away from the cells during division) or developmental arrest (when an embryo stops developing).
  • Sperm motility (movement): Sperm with low motility (asthenospermia) may struggle to reach and fertilise the egg through natural conception or IVF. Even if fertilisation occurs, impaired motility – depending on its cause – can impact early embryonic development, as the sperm may not deliver the essential signals and factors needed for optimal growth.
  • Sperm morphology: Sperm with abnormal morphology (size or shape) can affect fertilisation and embryo development. For instance, abnormal sperm may struggle to penetrate the egg, preventing fertilisation or causing abnormal embryo development. Structural defects, such as head or tail abnormalities, may prevent the sperm from properly interacting with the egg’s membrane, making fertilisation difficult in both natural conception and IVF.  Therefore, abnormal sperm morphology is indicative of low sperm quality.
  • Sperm epigenetics: Sperm carries epigenetic information – modifications that influence how genes function without changing the underlying DNA sequence. Disrupted sperm epigenetics can lead to improper gene expression in the embryo, increasing the risk of developmental issues, infertility or genetic disorders.
  • Oxidative stress: Sperm are vulnerable to oxidative stress – an imbalance between free radicals and antioxidants in the body – caused by factors such as smoking, alcohol consumption, environmental toxins or prolonged heat exposure. This oxidative damage can lead to DNA fragmentation, where sperm DNA strands break, potentially compromising embryo development after fertilisation.
  • Paternal age: As men age, their sperm quality may gradually decline, making conception more challenging. Although men do not experience a sudden decrease in fertility like women, ageing impacts sperm health, testicular function and pregnancy outcomes. For instance, older men may produce lower-quality sperm, reducing the chances of fertilisation. Sperm from older men are also more susceptible to DNA damage, which can increase the risk of miscarriage and DNA changes contributing to genetic conditions, including autism or schizophrenia in children.

Lifestyle changes to support sperm health

While some factors affecting sperm health are beyond control, lifestyle choices can play a significant role in improving sperm quality. Making positive changes may help enhance sperm function and increase the chances of successful conception. Suggestions that may assist with sperm quality include:

Keep the testicles cool

High temperatures can damage sperm. Avoid hot tubs, saunas, car seat warmers, placing your laptop on your lap for long periods, and carrying your mobile phone in your front pocket. Wear loose-fitting underwear to keep your testicles cool and prevent overheating.

Maintain a healthy diet

A balanced diet rich in vitamins, minerals and antioxidants from fruits, vegetables, nuts, seeds, whole grains and lean proteins can help protect sperm from damage.

Additionally, fertility-boosting nutrients such as vitamins C, E and folic acid, as well as zinc and selenium, have been linked to improved sperm quality. These are present in citrus fruits, leafy greens, eggs and nuts.

Consider fertility supplements

If you’re finding it difficult to obtain enough nutrients from your diet, you may wish to consider fertility supplements. Specifically, supplements such as zinc, folic acid, selenium and CoQ10 may support sperm health. However, please consult your fertility specialist before starting any new supplements.

Engage in regular exercise

Moderate physical activity can help maintain a healthy weight and improve overall health, which supports sperm production. However, excessive exercise or overtraining can have the opposite effect, leading to reduced testosterone levels and impaired sperm quality. Additionally, prolonged cycling (over 1.5 hours) should be avoided.

Avoid smoking and limit alcohol

Smoking and vaping are associated with poor sperm quality, including reduced count and motility and increased DNA damage. Quitting should be a priority for those looking to improve fertility.

Excessive alcohol consumption can also negatively affect sperm count and quality, so keep your intake to moderate levels for optimal reproductive health.

Maintain a healthy weight

Being overweight or obese can lead to hormonal imbalances, reduced sperm quality and lowered overall fertility. Achieving and maintaining a healthy weight through diet and exercise can help improve sperm health.

Avoid exposure to toxins

Minimise exposure to harmful chemicals such as pesticides, heavy metals and industrial toxins, as they can negatively affect sperm health. Avoid contact with pollutants in some cleaning products, plastics and air pollution – and skip drinking from plastic water bottles.

If chemical exposure is unavoidable (i.e. due to your work environment), always use appropriate protective equipment, such as gloves and masks, to reduce risk.

Attend regular medical assessments

Prioritising your overall health is essential, as conditions like diabetes, high blood pressure and infections can negatively affect sperm quality. Regular check-ups with your GP or healthcare professional can help detect and manage these issues early.

If you’re trying to conceive, inform your fertility specialist about any medications or supplements you’re taking, as some may impair sperm function.

Avoid drug use

Recreational drug use, such as marijuana or anabolic steroids, can significantly reduce sperm count and quality. If you’re using these substances, consider seeking help to quit.

Manage stress

Chronic stress can negatively impact hormone levels, affecting sperm production. Consider practising relaxation techniques like meditation, yoga, deep breathing, exercise or hobbies that help you relax.

Get enough sleep

Quality sleep is essential for overall health and plays a crucial role in hormone regulation. Poor sleep can disrupt hormone levels, including testosterone, which is vital for sperm production. To support reproductive health, prioritise restful sleep and aim for 7–9 hours of quality rest each night.

Limit caffeine intake

Excessive caffeine may negatively affect sperm quality. Limiting your intake to moderate levels (one or two cups per day) can be beneficial.

When to seek help

Making these lifestyle changes can help improve sperm quality over time. However, if you and your partner have been trying to conceive without success – 12 months if the female partner is under 35 years or six months if over 35 years – it may be time to seek specialist guidance. A fertility specialist can provide personalised advice and may recommend fertility testing to gain a clearer understanding of your reproductive health.

To book an appointment with one of our fertility specialists and explore your options, call Newlife IVF on (03) 8080 8933 or schedule a consultation online via our appointments page.

My doctor says we need ICSI – how will this improve our chances of a successful IVF cycle?

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The traditional IVF approach is to allow this meeting to take place ‘naturally’, albeit in a laboratory dish: the woman’s egg is placed in a special culture medium with a prepared semen sample containing thousands of sperm. The fittest sperm fertilises the egg, mimicking what would normally happen in the woman’s reproductive tract.

As its name suggests, ICSI is far more precise. Rather than leaving the egg and sperm to meet of their own accord in a laboratory dish, this technique allows us to directly inject a single sperm into a woman’s egg – thereby, overcoming any issues that may be getting in the way of a sperm and an egg meeting and coming together naturally. Here, we consider some of the reasons why ICSI may be considered during IVF and what specific fertility problems it can help overcome.

Who is ICSI suitable for?

When a couple is experiencing difficulties getting pregnant, it can be easy to focus solely on the woman’s fertility. However, a male factor contributes to infertility in approximately 40% of couples who fail to conceive.1 ‘Male factor infertility’ typically involves an alteration in the number, shape and/or movement of the man’s sperm, all of which can affect the sperm’s ability to fertilise an egg the natural way. ICSI is most commonly used to help overcome these types of sperm-related issues.

ICSI may also sometimes be offered if a woman has very few eggs available (e.g. due to age). In this case, ICSI is used to increase the chances of successful fertilisation, thereby lowering the risk that the woman runs out of eggs before she achieves a successful pregnancy through IVF.

ICSI may also be recommended if one or more previous standard IVF cycles were not successful due to failed fertilisation, or if the reason for cycle failure is unclear but a sperm-related issue is suspected despite a normal semen analysis.2

A checklist for fertile sperm

If your doctor suspects male factor infertility could be affecting your chances of pregnancy, they will usually suggest a semen (sperm) analysis. This is the main method used to test male fertility. During the analysis, a number of different factors that could be affecting your ability to conceive naturally are studied, including:

  • The volume of semen, which needs to be sufficient to transport sperm into the female reproductive tract
  • The sperm concentration and total sperm count, which affect the likelihood that enough sperm will reach the egg in order for one to fertilise it
  • The physical shape of the sperm, as abnormally shaped sperm can have difficulty swimming to the egg or penetrating the egg’s outer layer
  • The motility of the sperm (i.e. how well it can swim) – if large numbers of sperm in the sample are ‘weak swimmers’, then a natural pregnancy will be more difficult to achieve.

Your specialist might also recommend additional testing for:

  • Sperm DNA damage or fragmentation: sperm with damaged or fragmented DNA have a reduced chance of fertilising an egg
  • Sperm antibodies, which if present, can attack and impair sperm function.

Depending on your results, your doctor may then order follow-up tests to make sure the results are accurate and/or to see if anything else is preventing the semen from doing its job.

Once the tests are complete, your specialist will discuss your results with you and explain what your options are, including whether ICSI is likely to increase your chances of successful fertilisation and the overall success of your IVF treatment cycle.

Success rates with ICSI

Because of ICSI, many previously infertile men now have a good chance of fertilising eggs with their sperm. With some couples, pregnancy rates as high as 45% have been achieved with ICSI.3 However, rates this high are not always possible because of other factors, including age and egg quality.

The fertilisation of an egg and its subsequent development into a growing embryo is a complicated process, and there are many reasons why IVF may not be successful, even with the assistance of ICSI. To aid our success rates at Newlife IVF, we:

  1. Ensure an egg is suitable for fertilisation prior to ICSI: Using polarised light microscopy, we assess a structure inside the eggs called a ‘spindle’. We call this ‘egg spindle visualisation’. This allows us to identify if an egg is at a certain stage of development (called metaphase II) and therefore, in optimal condition for fertilisation via ICSI.
  2. Select the healthiest-looking sperm for ICSI: If the genetic information in the sperm has been damaged, or if the sperm is unable to use its DNA correctly, then there is a risk that development of the embryo will fail, even if it has been successfully fertilised via ICSI.4 A number of factors can increase this risk, such as smoking and older age.5,6 It’s not currently possible to know if the sperm we choose for ICSI is completely free of genetic defects. However, by using an advanced imaging system with an extremely high-powered microscope, we are able to study the structure of individual sperm, helping us to select the optimum sperm to inject into an egg. Sometimes, we may also use another technique, called intracytoplasmic morphologically selected sperm injection (IMSI), to help us pick out a healthier sperm based on its shape. A DNA test can also provide us with more details about sperm quality.
  3. Assess the best position to inject the sperm into the egg: Our extremely high-powered microscope also allows us to very precisely inject the selected sperm into the egg, such that we avoid an important structure inside the egg called the spindle. Research has shown that injecting eggs away from the spindle results in higher fertilisation rates and better embryo quality.

Still have questions?

If you are concerned about the possibility of male factor infertility or would like more information about the role of ICSI in an IVF treatment cycle, you can make an appointment with one of our fertility specialists by calling Newlife IVF on (03) 8080 8933. You can also book online via our appointments page.

References

  1. Agerwal A et al. Reprod Biol and Endocrinol. 2015;13:37–46. ↩
  2. Palermo GD et al. Sem Reprod Med. 2015;33:92–102. ↩
  3. Palermo GD et al. Sem Reprod Med. 2009;27:191–201. ↩
  4. Colaco S & Sakkas D. J Assisst Reprod Genet. 2018;35:1953–1968. ↩
  5. García-Ferreyra J et al. Clin Med Insights. Rep Health 2015;9:21–27. ↩
  6. Zini A & Sigman M. J Androl 2009;30:219–229. ↩