IMSI stands for Intracytoplasmic Morphologically Selected Sperm Injection.

This technique, used in in vitro fertilisation (IVF) treatments, is similar to ICSI in that it involves injecting a sperm into the egg. However, the difference lies in the selection of the sperm, which is done using a microscope capable of magnifying the image more than 6,000 times. This high-resolution microscope is linked to specialised software that controls its function. This high magnification enables the visualisation of structures and abnormalities in the sperm that cannot be seen with conventional microscopes.

Studies show that there is a correlation between morphological and structural alterations in the sperm head (for example, the presence of vacuoles) and DNA damage. This can lead to a decrease in fertilisation rates, embryo implantation, and ultimately, pregnancy rates.

IMSI makes it possible to select sperm with better morphology, thereby increasing the chances of success in IVF treatment and reducing the risk of miscarriage.

This technique is not recommended for all couples undergoing IVF, but it has shown better results in patients with previous IVF failures, high DNA fragmentation in the sperm sample, and in cases of severe male factor infertility.