IMSI, ICSI, IVF.. the abbreviations may seem endless when it comes to reproductive technology!
But behind the world of IVF, lay some procedures and techniques that cater to specific populations.
Not everyone’s IVF journey may be the same, not all tests recommended are similar, and not all clinics offer the same treatment.
IMSI is one such procedure that is catered to a section of IVF patients who face repeated failures, have severe male factor infertility, or have genetic abnormalities.
So what is this test, and how is it? Should you go for IMSI, if recommended?
We cover all this in this post and more. Read on to find out!
Table of contents
- Who is IMSI recommended for?
- How does IMSI work?
- How does IMSI help with higher pregnancy rates?
- Risks and limitations of IMSI
Who is IMSI recommended for?
IMSI is not a routine procedure, but is rather a specific procedure recommended for patients with:
1. Severe Male Factor Infertility
IMSI is often recommended when the male partner has a significantly low sperm count (oligospermia), poor sperm motility (asthenospermia), or a high percentage of abnormally shaped sperm (teratozoospermia). In such cases, IMSI aims to select the highest quality sperm for fertilization.
2. Repeated IVF or ICSI Failures
Couples who have experienced repeated IVF or ICSI failures may benefit from IMSI. This technique can help overcome fertilization issues caused by poor sperm quality, reducing the risk of failed fertilization.
3. Previous cases of Abnormal Embryos
If a couple has previously had IVF cycles with embryos that had genetic abnormalities or resulted in miscarriages, IMSI may be suggested to improve sperm selection and reduce the risk of embryo abnormalities.
4. Advanced Maternal Age
A study also supports the fact that in cases where the female partner has advanced maternal age, IMSI might be considered to optimize the chances of fertilization and the development of healthy embryos.
5. Unexplained Infertility
IMSI may also be recommended when the cause of infertility is unexplained, and the male partner’s sperm quality appears to be a potential contributing factor.
6. Genetic Concerns
In situations where there are concerns about the genetic integrity of the sperm, IMSI can help minimize the risk of passing on genetic abnormalities to offspring by selecting sperm with better morphology.
How does IMSI work?
To understand the IMSI procedure better, here’s a step-by-step guide:
1. Sperm sample selection and preparation
The patient sample is collected via containers, liquefied, and processed for evaluation. Most often, density gradient centrifugation is used for IMSI samples.
2. High-magnification microscopy
A specialized microscope [A Nomarski lens with optics and high magnification] is used to observe the sperm sample. This high-magnification equipment is attached to the existing ICSI microscope to view the sample at almost 6000x magnification. Additionally, the maximum magnification that the lens can offer is up to 13000x.
3. Spermatozoa evaluation and selection
This is when embryologists assess sperm morphology in detail, as per the Kruger criteria and MSOME. MSOME is a process known as motile sperm organelle morphology examination which enables examining the minute aspects of a sperm’s physical appearance, in real time.
Morphologically normal sperm are detected at this stage, separating them from ones with abnormal traits.
4. Injection of selected sperm into the egg
This is the stage where the chosen healthy sperm is injected into the egg to facilitate fertilization.
How does IMSI help with higher pregnancy rates?
The high magnification microscopy used in IMSI is the major distinguishing factor compared to conventional ICSI. While conventional ICSI magnifies sperm to around 400x magnification, IMSI is much higher at 6000x magnification.
Apart from these, some other factors that may contribute to higher pregnancy rates with IMSI include:
- The higher magnification ensures even the tiniest of abnormalities are observed, for a more accurate selection of morphologically normal, viable sperm
- Reduced risk of fertilization failure due to the injection of healthy, normal sperm
- Quality sperm injection reduces the risk of genetic abnormalities. This in turn enhances the chances of fertilization and healthy embryo development
A study done in 2015 evaluated the success of the parameters of IMSI cycles compared to conventional ICSI cycles. They found better quality blastocysts at day 3, better morphology, and better implantation rates, compared to conventional ICSI.
However, another study claims no significant difference in parameters, but rather how IMSI is a step towards better lab and clinical outcomes for the male infertile group.
Risks and Limitations of IMSI
While IMSI is generally safe, potential risks and side effects may exist, as with other procedures. Some of them are:
- Ethical considerations in IMSI: This is an ongoing process, where the implications of selecting certain traits in sperm and potential concerns for the future arise
- Costs associated with IMSI: IMSI may incur additional costs in IVF treatments, which patients should be informed of beforehand, by clinicians
- No specific indication: IMSI is often recommended as a second line of treatment, post careful evaluation. There is no specific indication that directs patients to IMSI procedures
- Procedural expertise: The duration of IMSI is longer compared to ICSI, which requires careful handling and quick evaluation from the embryologist’s end. The embryologist must be efficient and competent enough to avoid any risks associated with longer exposure of the gametes in the lab.
Ultimately, IMSI is a protocol that’s best recommended for a specific class of patients. While it’s not a routine procedure yet, there are several studies still evaluating its benefits, comparing it with standard procedures such as ICSI. However, the benefits for affected populations are clear and can aid in an embryo with better in vitro development and implantation potential.
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References
- Luna, D., Hilario, R., Dueñas-Chacón, J., Romero, R., Zavala, P., Villegas, L., & García-Ferreyra, J. (2015). The IMSI Procedure Improves Laboratory and Clinical Outcomes Without Compromising the Aneuploidy Rate When Compared to the Classical ICSI Procedure. Clinical Medicine Insights. Reproductive Health, 9, 29–37. https://doi.org/10.4137/CMRH.S33032
- Garolla, A., Fortini, D., Menegazzo, M., De Toni, L., Nicoletti, V., Moretti, A., Selice, R., Engl, B., & Foresta, C. (2008). High-power microscopy for selecting spermatozoa for ICSI by physiological status. Reproductive Biomedicine Online, 17(5), 610–616. https://doi.org/10.1016/s1472-6483(10)60307-0
- Marci, R., Murisier, F., Lo Monte, G., Soave, I., Chanson, A., Urner, F., & Germond, M. (2013). Clinical outcome after IMSI procedure in an unselected infertile population: A pilot study. Reproductive Health, 10(1), 16. https://doi.org/10.1186/1742-4755-10-16Setti, A. S., Figueira, R. C. S., Braga, D. P. a. F., Aoki, T., Iaconelli, A., & Borges, E. (2013). Intracytoplasmic morphologically selected sperm injection is beneficial in cases of advanced maternal age: A prospective randomized study. European Journal of Obstetrics, Gynecology, and Reproductive Biology, 171(2), 286–290. https://doi.org/10.1016/j.ejogrb.2013.09.006