IVF And IMSI
Intracytoplasmic morphologically-selected sperm injection (IMSI) is an infertility treatment developed in 2004 by Benjamin Baartov of Bar Ilan University, Israel - and is believed by some experts to be the most effective treatment to date for male factor infertility. The technique involves selecting the best quality sperm cells from a sample provided by the male partner, and injecting them directly into the eggs retrieved from the female partner, thereby increasing the probability that these sperm cells will fertilize the eggs.
Building On Past Successes
Studies have found that IMSI improves on the successes of ICSI (Intracytoplasmic sperm injection). ICSI, developed in the early 1990s, has itself been found to increase the chances of successful IVF. A 2008 study conducted in Italy reported that men who have tried and failed to become fathers through at least two previous IVF attempts were twice as likely to succeed through IMSI than through another round of conventional fertility treatment.
IMSI Versus ICSI Versus IVF
In IVF, eggs are harvested from the female partner and left in a dish with sperm cells from the male partner. These sperm cells need to be strong enough (have good enough 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 - both techniques give the sperm cells a helping hand to reach the inner layer of the egg (the cytoplasm). Where IMSI differs from ICSI, however, is that during IMSI, the embryologist carrying out the procedure uses an extremely high-powered microscope to select the sperm cells with the best morphological quality to be injected into the eggs.
Under The Microscope
In a report from July 7, 2008, the UK's Times Online reported that IMSI involves "examining sperm under a high-magnification microscope, about five times more powerful than standard laboratory equipment, to select those with a shape and size that indicates good genetic quality." And it seems that this high-magnification technology really does work.
Based on the Italian study mentioned above, involving 446 couples in which the male was infertile but the woman had no perceivable fertility problems, the pregnancy rate among the IMSI couples was 32.9% as opposed to 26.5% among the couples who used ICSI.
How Is It Done?
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, where fertilization can take place. The eggs and sperm are then left for 24 hours, during with fertilization is likely to occur. If this is indeed what happens, the now fertilized eggs (embryos) are transferred back to the woman's uterus where hopefully at least one will implant, resulting in a pregnancy.
Risks And Disadvantages
Experts say that IMSI is significantly more expensive to perform than ICSI, because of the need for specialized training and expensive state-of-the-art equipment. There is also the possibility of a higher risk of multiple pregnancy (twins or triplets) arising from IMSI than from ICSI.