It stands for Intracytoplasmic morphologically selected sperm injection. This is a technique that is best used for enhancing the chance of successful fertilization and lowering the chances of miscarriage. In this technique, sperms are thoroughly examined by expert embryologist under microscope with magnification of 6500x.
The embryologist examine the sperm for their morphology and discard sperms with poor morphology. In general practice, standards laid out by WHO for morphology of healthy sperm is followed. According to the standards, sperm should be 2.5 – 3.5 micron wide, length should be around 4.5 microns and it must have an oval shaped head.
Though IMSI or Intracytoplasmic morphologically selected sperm injection could be safely used as a replacement method of ICSI; thereby, enhancing the chances of pregnancy but the major indications of IMSI are acute cases of male infertility factors and repeated failures of IVF process due to miscarriages.
As a fact, miscarriages are largely caused due to poor quality of sperm that fertilized the egg. Even when the fertilization is through ART, the morphology or quality of sperm remains undetermined, unless IMSI is used. Then, with Intracytoplasmic morphologically selected sperm injection, the sperm which is injected is already screened for its quality and morphology; thereby it drastically lowers the chance of miscarriage.
IMSI is a rather new processes but its high success rate has made it a popular choice for insemination and fertilization of egg before moving ahead with IVF or other similar assisted reproductive technique. However, there are no metrics associated for it success rate. As per popular and expert infertility treatment doctors, the success rate of IMSI is as high as 99%.