Definition and Clinical Relevance
Immotile sperm are spermatozoa that lack movement, which is typically a key indicator of viability and fertilization potential. Immotility is commonly encountered in severe male infertility, especially in cases involving testicular sperm extraction (TESE) or conditions like immotile cilia syndrome.
Causes of Sperm Immotility
Genetic disorders (e.g., immotile cilia syndrome/Kartagener syndrome).
Severe spermatogenic failure or azoospermia, often requiring surgical sperm retrieval.
Assessment of Viability in Immotile Sperm
Motility is not always indicative of viability; specialized tests are needed to identify live but immotile sperm.
Common techniques:
Hypo-osmotic swelling test
Chemical induction of tail movement
Sperm tail flexibility test Laser-assisted selection
Assisted Reproductive Techniques Using Immotile Sperm:
Intracytoplasmic sperm injection (ICSI) allows fertilization with immotile but viable sperm.Laser-assisted selection and other viability tests improve the selection of functional sperm for ICSI.
Outcomes of Using Immotile Sperm in ART
Fertilization and pregnancy are possible with immotile sperm, though rates are generally lower compared to motile sperm.Use of calcium ionophore may improve fertilization outcomes in TESE-ICSI cycles with immotile sperm.No significant negative impact on obstetric or neonatal outcomes when using laser-selected immotile sperm.
Cryopreservation of Immotile Sperm:
Viable immotile sperm can be successfully frozen and later used for ICSI, offering fertility preservation options for men with total sperm immotility.
Recent Advances:
High-frequency ultrasound and laser techniques are emerging as noninvasive methods to improve or assess sperm motility and viability.
Clinical Implications and Counseling:
Patients with immotile sperm should be counseled on the available techniques, expected outcomes, and fertility preservation options
Immotile sperm, which lack the ability to swim, are a significant cause of male infertility. However, advancements in reproductive medicine now offer hope for individuals facing this challenge. Here’s a comprehensive look at immotile sperm, their implications, and the latest solutions available.
What Are Immotile Sperm?
Immotile sperm are spermatozoa that show no movement, even under microscopic examination. While motility is a key factor for natural conception—sperm must “swim” through the female reproductive tract to reach the egg—immotility doesn’t always mean the sperm are non-viable.
Key categories of sperm motility:
• Progressive motility: Sperm swim in straight lines or large circles.
• Non-progressive motility: Sperm move but lack purposeful direction.
• Immotile: No movement at all.
Causes of Immotility
Immotility can stem from:
• Genetic disorders: Such as immotile cilia syndrome (Kartagener syndrome), where structural defects in sperm tails prevent movement.
• Testicular dysfunction: Seen in cases of severe spermatogenic failure or after surgical sperm retrieval (e.g., testicular sperm extraction).
• Environmental factors: Exposure to toxins, smoking, or excessive heat.
Assessing Viability in Immotile Sperm
Motility ≠ viability. Specialized tests identify live sperm for use in fertility treatments:
1. Hypo-osmotic swelling (HOS) test: Viable sperm tails curl in a specific solution.
2. Laser-assisted selection: A laser shot triggers tail movement in live sperm.
3. High-frequency ultrasound: Noninvasive exposure can temporarily activate motility in some sperm.
Treatment Options for Immotile Sperm
1. Intracytoplasmic Sperm Injection (ICSI)
• A single viable sperm is injected directly into an egg, bypassing the need for motility.
• Success rates depend on sperm viability, not movement.
2. Emerging Technologies
• Ultrasound activation: A 2024 study showed that 40 MHz ultrasound exposure boosted motility in 34% of immotile sperm, with 25% becoming progressively motile.
• Laser viability testing: Rapidly identifies live sperm without damaging DNA.
3. Cryopreservation
• Immotile but viable sperm can be frozen for future ICSI cycles. Techniques like vitrification minimize damage during freezing.
Outcomes and Considerations
• Fertilization rates: Lower than motile sperm but achievable. For example, laser-selected immotile sperm yield fertilization rates comparable to motile sperm in ICSI.
• Pregnancy success: No increased risk of birth defects when using viability-tested sperm.
• Fertility preservation: Critical for men undergoing cancer treatment or with progressive infertility.
Recent Advances
• Noninvasive motility induction: High-frequency ultrasound offers a chemical-free method to transiently activate sperm, aiding selection for ICSI.
• AI and machine learning: Emerging tools improve sperm selection accuracy and predict surgical outcomes.
Key Takeaways for Patients
• Testing is crucial: Always confirm viability through HOS, laser, or ultrasound methods before discarding immotile sperm.
• ICSI is effective: Even with zero motility, viable sperm can lead to successful pregnancies.
• Explore new technologies: Ask fertility specialists about ultrasound or laser-assisted techniques.
While immotile sperm pose challenges, modern reproductive technologies continue to break barriers, offering realistic pathways to parenthood. Consulting a fertility expert can help tailor these solutions to individual needs.
Refference
Chen, H., Feng, G., Zhang, B., Zhou, H., Shu, J., & Gan, X. (2017). A successful pregnancy using completely immotile but viable frozen-thawed spermatozoa selected by laser. Clinical and Experimental Reproductive Medicine, 44, 52 – 55. https://doi.org/10.5653/cerm.2017.44.1.52
Shulman, A., Feldman, B., Madgar, I., Levron, J., Mashiach, S., & Dor, J. (1999). In-vitro fertilization treatment for severe male factor: the fertilization potential of immotile spermatozoa obtained by testicular extraction.. Human reproduction, 14 3, 749-52. https://doi.org/10.1093/HUMREP/14.3.749
Çayan, S., Conaghan, J., Schriock, E., Ryan, I., Black, L., & Turek, P. (2001). Birth after intracytoplasmic sperm injection with use of testicular sperm from men with Kartagener/immotile cilia syndrome.. Fertility and sterility, 76 3, 612-4. https://doi.org/10.1016/S0015-0282(01)01974-4
Chen, H., Wang, C., Zhou, H., Shu, J., Gan, X., Xu, K., Wu, Z., Deng, X., Huang, G., & Lin, R. (2021). Laser-assisted selection of immotile spermatozoa has no effect on obstetric and neonatal outcomes of TESA-ICSI pregnancies. Reproductive Biology and Endocrinology : RB&E. https://doi.org/10.1186/s12958-021-00835-9