What is IMSI?

Intracytoplasmic morphologically selected sperm injection (IMSI) is a sperm selection method used in intracytoplasmic sperm injection (ICSI). The technique involves using a microscope to view sperm under very high magnification (over x6000). This allows a detailed image of sperm and to select sperm that have less vacuoles. IMSI may be offered in cases where fertilisation has been poor with ICSI.

Risks of IMSI

IMSI is a non-invasive test performed on a semen sample as an additional step in the ICSI process. The risks associated with the use of ICSI also apply to IMSI; there are no significant additional risks to the patient or embryo.


RCTs and all studies carried out on infertile men found no impact of IMSI on live birth rate. One study reported a statistically significant difference with older women. A theory for this observation was that older eggs were less able to ‘fix’ DNA damage in sperm which is thought to be reduced with techniques such as ICSI and IMSI.

Current HFEA grading

For more information, please visit the HFEA website

Your next step.

When you are ready and the time is right for you, the next step is to contact us and we will help you arrange a face-to-face, telephone or video-call introduction with one of our consultants.

You can do this by filling in the contact form below or by giving one of our friendly team a call on +44 (0) 203 263 6025 or emailing us at