Advanced sperm selection techniques in IVF: How fertility clinics use sperm selection technology to improve success
Overview of selection methods in assisted reproduction
In assisted reproductive treatments like IVF and ICSI, the quality of the sperm used can significantly influence the outcome. While the focus is often on the egg, sperm selection plays an equally important role – especially when considering IVF success rates, embryo development and long-term pregnancy outcomes.
Over the past years, clinics and embryologists have introduced a range of laboratory-based sperm selection methods to improve fertilisation, embryo quality and overall IVF success. These techniques go far beyond traditional approaches and aim to isolate the most viable sperm cell – based on motility, morphology and DNA integrity.
For couples struggling with infertility or those planning IVF treatment, understanding how sperm is selected – and which options are available – can offer clarity and confidence. This overview outlines key sperm selection technologies currently used in reproductive medicine, from basic preparation steps to advanced sperm selection techniques such as IMSI and microfluidic sperm selection.
Whether you are exploring fertility treatment for the first time, comparing IVF clinics, or seeking answers after a previous IVF failure – this guide provides a structured overview of the most relevant sperm selection tools in assisted reproduction today.
Older sperm handling techniques still mentioned in IVF clinics
Some sperm preparation techniques used in early IVF cycles are still mentioned today, though they are no longer considered standard in assisted reproductive treatments. Their main purpose was to separate more active sperm from the rest of the sample. However, these older methods do not provide insights into DNA quality, morphology or long-term fertilisation potential.
Swim-up preparation and its limited role in IVF treatment
The swim-up method allows motile sperm to move into a clean medium, leaving behind less active or abnormal cells. While simple and non-invasive, this technique does not evaluate sperm morphology or DNA integrity. It is rarely used in modern IVF or ICSI procedures, where a single sperm is injected directly into the egg.
Density gradient preparation in assisted reproductive technologies
Density gradient centrifugation separates sperm based on their density and structure. It helps reduce debris and select more structurally intact cells. However, it does not actively identify the best-quality sperm. This method is sometimes used before ICSI, but newer sperm selection technologies are preferred in most fertility clinics to improve success rates.
Biochemical and viability-based techniques in male infertility
In cases of male factor infertility, standard preparation is often not enough. Several biochemical methods help assess sperm functionality, including binding ability, membrane integrity and early cell death. These tests are used to evaluate sperm quality before selecting a sperm cell for ICSI or other assisted reproductive procedures.
HBA test and sperm quality assessment
The hyaluronan binding assay (HBA) measures a sperm cell’s ability to bind to natural substances found around the egg. A high binding rate is often linked to better sperm maturity and lower DNA fragmentation. HBA can be used in fertility clinics to support sperm selection for intracytoplasmic sperm injection, particularly when morphology or motility are poor.
HOST and sperm viability in vitro fertilization
The hypo-osmotic swelling test (HOST) helps embryologists determine if a sperm cell is viable based on how its membrane reacts to a controlled environment. Swelling indicates an intact membrane, which is important for successful fertilisation. HOST is not a selection method on its own but may be used to guide sperm choice in cases of low motility during IVF treatment or ICSI.
Using apoptosis markers in fertility treatment
Some sperm show early signs of programmed cell death, known as apoptosis. By identifying these cells with specific markers, labs can reduce the risk of selecting damaged sperm. This test is not routine but may be useful for couples with repeated IVF failure or unexplained infertility. It is sometimes combined with magnetic selection techniques or other advanced sperm selection methods.
“Even if you face OAT and the numbers look discouraging, remember that only one good sperm is enough to fertilise an egg – and that single sperm can be the start of a new life.”
Nathalie Wiederkehr
Advanced sperm selection techniques for better IVF success
Some fertility clinics use advanced sperm selection techniques to improve fertilisation and embryo quality, especially in cases of male infertility or previous IVF failure. These methods go beyond basic preparation and aim to select sperm based on genetic integrity, structure and function. Each technique serves a different purpose and may be considered depending on the patient’s history, sperm parameters and overall IVF treatment plan.
ICSI – Intracytoplasmic sperm injection in IVF
ICSI is one of the most widely used IVF techniques, especially in cases of male factor infertility or poor semen quality. It involves selecting a single sperm and injecting it directly into the egg, bypassing the natural fertilisation process. This approach is now considered standard in many fertility clinics.
The selection of sperm for intracytoplasmic sperm injection is often done manually, using basic visual assessment under a microscope. While this method has high fertilisation rates, it does not guarantee optimal sperm quality. That’s why many fertility centres now combine ICSI with more advanced sperm selection methods such as IMSI, PICSI or MACS to improve embryo quality and pregnancy rates.
ICSI is not an add-on in most clinics, but a core part of assisted reproductive treatments. It plays a central role in IVF success, especially for couples dealing with male infertility.
IMSI – Intracytoplasmic morphologically selected sperm injection
IMSI is an extended version of ICSI that uses a much higher level of magnification – up to 6000x – to examine fine details of the sperm’s structure. In contrast, standard ICSI is performed at around 400x magnification and focuses mainly on motility and basic shape.
By using IMSI, embryologists can detect small vacuoles or head abnormalities that are not visible under conventional microscopes. This detailed view helps select the best-quality sperm, especially in cases of repeated IVF failure, poor sperm morphology or unexplained infertility. IMSI is considered part of advanced sperm selection and may improve embryo development in selected cases.
While IMSI is not necessary for all patients, it can be a useful tool when other sperm selection methods do not provide the desired results – particularly in IVF cycles involving intracytoplasmic sperm injection.
PICSI and its role in sperm selection technology
PICSI uses a dish containing hyaluronic acid to mimic natural egg binding. Only mature sperm can attach to the surface, allowing for better-quality sperm selection. This technique is sometimes recommended when DNA fragmentation is suspected or sperm morphology is poor, particularly in IVF cycles involving ICSI.
MACS and factor infertility in male patients
Magnetic activated cell sorting (MACS) helps remove sperm showing early signs of apoptosis. By filtering out these damaged cells, MACS may improve the selection process in patients with high DNA fragmentation or other indicators of male factor infertility. It is sometimes used alongside other sperm selection methods during ICSI.
CASA and high-quality sperm analysis
Computer-assisted sperm analysis (CASA) provides a detailed assessment of motility, concentration and morphology. Unlike manual observation, this method delivers objective data on sperm movement and structure. CASA is used in many fertility clinics as part of a comprehensive diagnostic process, especially before advanced sperm selection.
DNA fragmentation tests and embryo quality
DNA fragmentation tests such as TUNEL or SCSA measure the integrity of genetic material inside the sperm cell. High levels of fragmentation can reduce embryo quality and lower the success rate of IVF and ICSI. These tests are typically used when no other cause of infertility is found, or when embryo development has failed in previous cycles.
Microfluidic and AI-assisted sperm selection methods
Recent advances in reproductive medicine include new tools that use artificial intelligence and microfluidic technology to improve how sperm are selected in IVF and ICSI treatments. These methods aim to reduce human error and avoid physical stress on the sperm during the selection process. While not yet used in every clinic, they represent a growing trend in assisted reproduction.
Advanced sperm selection methods using microfluidic chips
Microfluidic sperm selection uses a small chip that mimics the natural barriers of the female reproductive system. Only highly motile sperm with intact membranes can pass through the channels, making this a gentle and non-invasive method. This approach helps isolate viable sperm with low DNA fragmentation, and may support better embryo development and fertilisation outcomes. Microfluidic chips are now available in several fertility clinics and are often combined with ICSI.
AI-based analysis in sperm selection technology
Artificial intelligence is used to analyse sperm movement, shape and behaviour in more detail than the human eye can detect. This technology supports the assessment of sperm quality by identifying subtle defects in morphology or motility patterns. AI-based sperm selection technology is still under development, but early results suggest it could impact sperm selection decisions in future IVF cycles.
Combining AI and microchips to improve IVF success rates
Some systems now integrate AI with microfluidic sperm selection in a single device. The goal is to filter out damaged sperm and highlight those with the best potential for fertilisation. By removing variability in the selection process, these tools may improve embryo quality and support better IVF success rates – especially in cases of male infertility or previous IVF failure.
When surgical sperm retrieval is needed in male factor infertility
In some cases of male factor infertility, sperm must be retrieved directly from the testicles or epididymis. This is typically necessary when no sperm are found in the ejaculate due to obstruction or impaired production. Surgical sperm retrieval is often followed by ICSI to maximise the chances of successful fertilisation.
Using TESE and MESA in assisted reproduction
TESE (testicular sperm extraction) and MESA (microsurgical epididymal sperm aspiration) are common procedures used to obtain sperm when ejaculation is not possible. The retrieved sperm are usually immotile or immature, which makes precise selection even more critical. These methods are widely used in assisted reproductive technologies and are often combined with advanced sperm selection techniques before ICSI.
Immotile sperm activation and IVF techniques
In some cases, sperm retrieved through TESE or MESA are not moving. To use them for ICSI, embryologists may apply chemical or mechanical stimulation to activate the sperm. This process requires experience and careful lab conditions. If you want to learn more about how immotile sperm are handled in IVF treatment, we cover this in detail in a separate article.
When is advanced sperm selection needed in IVF clinics?
Not every IVF cycle requires high-tech sperm selection tools. However, in some situations, advanced techniques may increase the likelihood of fertilisation, embryo development or even embryo transfer. These methods are especially relevant when there are clear concerns about sperm function or past treatment failure.
Indications for advanced techniques in sperm selection methods
Advanced sperm selection is often considered when semen analysis shows poor sperm motility, abnormal morphology or high levels of DNA fragmentation. These factors can affect how likely a sperm cell is to fertilise an egg or support embryo growth. In such cases, standard sperm separation techniques may not be enough to identify viable sperm.
Couples with a history of IVF failure or cases of male infertility may also benefit from more refined methods. For example, when motility is low or the sperm appear structurally intact but fail to fertilise the egg, tools like IMSI or microfluidic sperm selection may offer better results. These options aim to replicate natural selection processes in a laboratory setting.
How to choose the right option in your fertility journey
The decision to use advanced sperm selection depends on multiple factors, including previous embryo quality, response to ICSI, and the overall cause of infertility. Some IVF clinics routinely use ICSI with basic visual selection, while others offer additional tools when needed.
If you’re exploring different options for IVF or looking for ways to improve fertilisation rates, it’s worth asking your fertility clinic which sperm selection methods are available. In some cases, the injection of a single sperm that has been carefully selected could improve the chances of embryo transfer and successful pregnancy.
Summary and next steps in choosing IVF destinations
Choosing the right clinic and treatment method is a key step in your fertility journey. Whether you’re just starting out or considering another attempt after IVF failure, understanding the role of sperm selection can help you make informed choices. While no technique guarantees success, using the best available tools for sperm and egg quality can make a measurable difference.
What to ask your IVF clinic before treatment
Before beginning IVF treatment, it’s helpful to ask your clinic how sperm selection is handled. Do they use standard visual checks, or offer options like IMSI or microfluidic sperm sorting? What is their approach if sperm motility is low, or if sperm morphology raises concerns?
You can also ask how embryos are cultured, whether egg retrieval and ICSI are done in-house, and what their average live birth rates are. In some cases, using a single sperm directly after detailed assessment may improve outcomes — particularly if egg and sperm quality is a concern.
Understanding your options for assisted reproductive care
Different IVF clinics offer different technologies, and not all have access to advanced sperm selection for assisted reproduction. In patients with male fertility issues, or where motile human sperm cells are rare, selecting the right lab method can be crucial.
Ask whether the clinic works with cases involving low sperm motility, how they assess the morphology of motile human sperm, and how they decide which sperm are more likely to fertilize the egg. These questions can give you insight into how closely the lab tailors the process to your needs.
Get the guide to IVF destinations and book a private consultation
If you’re comparing clinics or looking for support in evaluating your options, our free guide to IVF destinations in Europe offers a helpful starting point. It includes information on popular IVF countries, available treatments, costs and success rates, and where advanced sperm selection methods are used. The guide is designed to help you make informed, ethical and confident choices — with no clinic promotion.
You can also book a private consultation to discuss your specific situation, clinic availability and success data based on your medical background. We’ll help you choose the best IVF options for your personal path to parenthood.
