Understanding IMSI
Standard ICSI selects sperm at around 200–400× magnification. IMSI uses digital magnification of several thousand times, allowing embryologists to look for subtle structural features of sperm heads.
The rest of the process — stimulation, egg retrieval, injection and embryo transfer — follows the IVF/ICSI pathway.
Who may need this?
It may be considered in situations such as the following. Suitability is always decided after individual assessment.
- Selected couples with severe male factor infertility.
- Some couples with repeated unsuccessful ICSI cycles.
- Cases where sperm show a high proportion of abnormal forms.
How does it work?
- 01
Assessment
Review of semen analysis and previous treatment history.
- 02
IVF/ICSI cycle
Stimulation and egg retrieval as for IVF.
- 03
High-magnification selection
Sperm are examined at very high magnification.
- 04
Injection and culture
The selected sperm is injected into the egg, and embryos are cultured and transferred.
Potential benefits
- More detailed assessment of sperm appearance before selection.
- May be considered when previous ICSI outcomes were poor.
Important considerations
- Evidence on whether IMSI improves pregnancy rates is mixed; benefits vary and are not guaranteed.
- It is not routinely needed for most couples.
- Availability and suitability should be confirmed with the clinic.
Preparation
- Bring previous semen analyses and IVF/ICSI records.
- Preparation for the female partner follows the IVF pathway.
This information is educational and does not replace an individual medical consultation. Outcomes vary and no treatment can guarantee a particular result.
