IMSI – Intracytoplasmic Morphologically-selected Sperm Injection is a male infertility treatment developed by Benjamin Baartov of Bar Ilan University, Israel in 2004. The technique involves selecting morphologically ,the best quality sperms from husband’s semen sample, and injecting them directly into the eggs, retrieved from the female partner, thereby increasing the probability of these sperm cells to fertilize the eggs.
In the ICSI technique, the sperm is magnified 200 times whereas in the IMSI technique the sperm is magnified 7000 times. At such magnification the sperm morphological defects namely the subtle intra-nuclear sperm defects and the chromatin compaction defects get easily detected while conventional ICSI fails to identify the same. This leads to higher fertilization rates, higher implantation rates, and ultimately higher ‘take home baby’ rates. It also reduces early abortion rates. IMSI technique is immensely beneficial for patients with more than two ICSI failures, patients where there is severe male factor abnormality e.g. severe oligoasthenospermia / normal sperm count but higher percentage of abnormal sperms- Teratozoospermia, elderly male partners, in cases of recurrent first trimester abortions(here the conventional ICSI does succeed but results in early abortions), and in patients with prolonged Unexplained Infertility.
In IVF, eggs are harvested from the female partner and left in a dish with sperm cells from the male partner in appropriate ratio. These sperm cells need to be healthy enough with good morphological quality to swim to the eggs, penetrate their outer layers and fertilize them.
IMSI and ICSI do not rely on the sperm cells’ ability to do this – and morphologically best sperms are chosen by the embryologists using higher (7000 times) magnification and manually injected into the cytoplasm of the eggs. With this microscope, Biologists can see the internal morphology of sperm and discard those with abnormalities. Being able to select sperm without morphological alterations are believed to increase the chances of successful implantation of embryo and decrease the likelihood of miscarriage.
IMSI begins with standard IVF procedure. The female partner is given ovulation-inducing drugs, and the resulting mature eggs are then harvested from her ovaries and prepared for fertilization in the laboratory. The embryologist will then use the high-powered microscope to examine the male partner’s semen sample. He then uses a long, thin, hollow needle to pick up the desired sperm cell. He holds the egg cell in a special pipette, and then uses the needle to push the sperm cell through the outer shell of the egg and into its inner area (cytoplasm) , where fertilization can take place. The eggs and sperms are then left for 18-24 hours, checked for fertilization and embryo culture continues until uterine transfer ( day 3 or day 5 ).
A 2008 study conducted in Italy reported that men who have tried and failed to become fathers through at least two previous IVF – ICSI attempts were twice as likely to succeed through IMSI than through another round of conventional fertility treatment.
The IMSI may improve the chances of fertilisation in vitro and can use it if you have performed several In Vitro Fertilization, IVF, ICSI without success.