Intra-cytoplasmic Morphologically Selected Sperm Injection (IMSI)

imsi procedure

In this IMSI photograph, arrows point to two sperm with round patches inside the head of the sperm. The two sperm at the bottom of the photograph are considered ‘normal’.

When there is significant male infertility, the embryologist injects a sperm into each egg using a technique called ICSI. IMSI is a variation of ICSI (Intracytoplasmic sperm injection) using higher magnification, that allows the embryologist to look at the sperm head in detail.

Benefits of IMSI:

  • Higher pregnancy rates have been reported in selected groups of patients.
  • The chance of miscarriage may be reduced by selecting better sperm.

Useful to know:

  • IMSI is not useful for sperm taken directly from the testis.


How IMSI works:

  • Washed sperm are viewed at a magnification 600 times their normal size.
  • This magnification shows irregular features in sperm heads that otherwise cannot be seen.
  • The embryologist then chooses sperm with the most normal looking heads.

Who can benefit from IMSI?

  • Men with poor sperm morphology because poor morphology makes sperm more susceptible to oxidation damage.
  • Men with a higher level of DNA fragmentation in their sperm (DNA fragmentation is a sign of oxidation damage).
  • People with few embryos developing to the blastocyst stage.
  • People who have not become pregnant despite the transfer of several reasonable quality embryos.