These days, the IMSI procedure allows IVF with morphological selection of the spermatoa, before it is injected into the egg.
This state-of-the-art technique has many benefits for men with teratoozospermia, where the majority of sperm have an abnormal structure. By selecting the sperm with the best morphology, we increase the odds of pregnancy occuring.
Provided below is an index with the 8 points we are going to expand on in this article.
What does IMSI consist of?
The ongoing improvements in the field of Assisted Reproductive Technology (ART) allow improved and innovative techniques to become available for IVF patients. All of these techniques are developed to increase the success rates of fertility treatments.
IMSI, sometimes also known as Super-ICSI, is one of these cutting-edge technologies. It uses a special lens for the microscope, to study the sperm under very high levels of magnification, greater than 6300x. This is a major advantage in comparison with ICSI, in which sperm are selected individually under a less powerful microscope at 400x magnification.
Thus, IMSI allows the embryologist to see the structure of spermatozoa in great detail, allowing them to detecting potential defects in the head, middle-piece, and/or tail.
According to the World Health Organization (WHO), for a sperm cell to have an excellent morphology, it must have the following characteristics:
- Oval head
- Straight or uncoiled tail
- Fixed nucleus
- Transparent color
Additionally, the sperm must have their acrosome intact and not contain vacuoles in their interior. You can find more information about spermatozao in this article: Sperm Cells, definition and structure.
ICSI o IMSI?
Currently, the most widely used technique used in IVF cycles is ICSI, especially in cases of severe male infertility, or when the sperm count, motility, or morphology are affected.
However, ICSI is a subjective technique, as it is the specialist who chooses the sperm cells, following his personal criteria when observing the head, middle-piece, and tail.
Thanks to IMSI and the improvements that it brings to the process of examining and selecting sperm, we have seen the pregnancy success rates improve in cases of male infertility.
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When we select the sperm with the best morphology, the spermatozoa with poor morphology are ruled out depiste their potential ability to fertilize the egg. Poor morphology is associated with implantation failure and a higher risk of miscarriage. Therefore, motile spermatozoa without alterations and without vacuoles in the nucleus are chosen.
Another difference between ICSI and IMSI is the magnification at which the sperm is observed. In the case of ICSI, the microscope used is 400X. IMSI, on the other hand, offers an image magnified over 6000 times, allowing a much better evaluation of the sperm both externally and internally.
When is IMSI used?
Severe male factor infertility is one of the most common causes of not be able to get pregnant. It is estimated that 30% of infertility cases are due to a male factor. For example, if a man has low sperm quality a low sperm count, lazy or slow-moving sperm, or abnormal sperm morphology.
IMSI technique is particularly recommended when sperm morphology is the defect, a disorder that is known as teratozoospermia or teratospermia.
Selecting sperms with a good, normal morphology increases the pregnancy success rates in patients with infertility problems.
In addition, IMSI is used in the following cases:
- Failure of fertilization with ICSI failure
- Poor quality embryos that stop growing
- Implantation failure
- Severe oligoasthenoteratozoospermia
- Severe sperm DNA fragmentation
- Long-term unexplained infertility
It should be noted that IMSI is not used on a standard basis in IVF labs. It is used only in special cases, as the cost is considerably high and it does not necessarily increase the success rates in all cases.
Benefits of IMSI
The main benefit of IMSI is that it allows for an detailed visualization of sperm cells, thanks to magnification level of 6300X their normal size. This is an optical increase 15 times more powerful than in conventional IVF/ICSI cycles.
Furthermore, with IMSI live sperm can be selected in real time. As such, the use of dyes that could damage the sperm cells becomes unecessary.
Visualizing the sperms in such great detail not only allows us to detect potential head defects, but also in the middle-piece or neck, and the tail. The presence of such defects is associated with sperm DNA fragmentation.
In general, the IMSI technique has resulted in an increase in fertilization and pregnancy rates, whilst decreasing the miscarriage rate.
Disadvantages of IMSI
In spite of all the advantages that IMSI can add to your fertility treatment, it also has some disadvantages that one should consider, including:
- It adds a considerable amount of extra time to the IVF procedure: about 1.5 to 5 hours.
- Due to its elevated cost, it is not available in all IVF laboratories.
For all these reasons, IMSI is used only when sperm quality is very poor or in cases of repeated IVF or IVF with ICSI failure.
More research is necessary for this technique in order to prove its clinical efficacy and determine the cases where it should be applied.
FAQs from users
What are the advantages of IMSI?
Selection of individual sperm under high magnification microscope, (intracytoplasmic morphologically selected sperm injection or IMSI), allows the use of the most apparantly optimal sperm according to shape (morphology) in men with the most severe male factor.
IMSI is considered for patients with recurrent implantation failure or spontaneous miscarriages (Lo Monte et al. 2013) due to the opinion the pregnancy failures were due to a sperm defect. However, recent studies have opposed this view by showing IMSI does not improve outcomes for men undergoing multiple IVF cycles. (Oliveira et al. 2011, Gatimel et al. 2016).
Is any special preparation required prior to IMSI?
A priori, IMSI does not require any special preparation prior to its performance. The process for IMSI is identical to ICSI, the only difference being the microscope used to select the sperm.
What is the difference between IMSI and conventional ICSI?
Both are laboratory techniques that consist of injecting a spermatozoon into an egg. These spermatozoa are selected using morphological criteria, which are evaluated under the microscope.
In IMSI the microscope has 6000 magnification and in ICSI 400, so the fundamental difference between the two techniques lies in the sperm selection based on morphology.
Is IMSI possible with lazy sperm?
Yes, IMSI is possible with sperm samples that contain sluggish sperm, that is, samples with asthenozoospermia, as long as it is indicated for the reasons explained above.
The main purpose of IMSI is to select the sperm cells with the best morphology only. To select sperms with progressive motility conventional ICSI is sufficient since IMSI would not add any benefits.
How is IMSI performed?
The IMSI procedure is the same as in ICSI cycles. First, the sperm sample is processed in the lab, and the pellet is resuspended at the adequate concentration. The only difference between IMSI and ICSI is the microscope used to select the sperms morphologically with IMSI. This type of microscope is based on the MSOME technology (Motile Sperm Organelle Morphology Examination), which is equipped with a digital imager.
Once the embryologist selects the best sperms, they are transferred to the ICSI plate and taken to a conventional microinjector to fertilize the eggs.
What is special about IMSI?
IMSI stands for intracytoplasmic morphologically selected sperm injection. This is an ICSI in which the sperm to be microinjected has been carefully selected based on its morphology. In order to select the sperm, ICSI is performed under a high magnification microscope that allows the morphological qualities of the sperm to be seen in detail.
Therefore, IMSI is an ICSI performed under a 6300 magnification microscope instead of the usual 400 magnification of ICSI.
Why is IMSI such a slow technique?
Because it is a very laborious technique that can be only by conducted by highly trained professionals. It often requires two embryologists to work simultaneously in order to reduce the duration of the process and perform it more objectively.
Moreover, due to the use of a more powerful microscope, finding sperm cells under the microscope becomes a difficult task, making it a technically challenging technique.
We have mentioned teratozoospermia as the main indication for the use of IMSI. To get a deeper insight on this sperm disorder, we recommend visiting the following post: What Is Teratozoospermia? – Causes, Pregnancy Rate & Treatment.
According to the WHO, a semen analysis is the most useful tool when it comes to evaluating male fertility, as it can detect potential sperm disorders. Learn more about sperm analysis here: What Is a Semen Analysis Report? – Purpose, Preparation & Cost.
Today, ICSI is the most widely used technique in IVF labs. You can get more information on this by clicking the following link: What Is ICSI Technique? – Process, Success Rates & Cost.
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FAQs from users: 'What are the advantages of IMSI?', 'Is any special preparation required prior to IMSI?', 'What is the difference between IMSI and conventional ICSI?', 'Is IMSI possible with lazy sperm?', 'How is IMSI performed?', 'What is special about IMSI?' and 'Why is IMSI such a slow technique?'.
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