ICSI is considered an ‘add-on to traditional IVF or Reciprocal IVF & so is not a treatment on it’s own but additional help you may require to ensure you get fertilised embryos. It is a specialist technique in which a single sperm is injected into the centre of an egg. It may be offered to you in the days following ‘egg collection’ when the lab check the sperm & advise you that the sperm to be used is not optimal, often because of low sperm count or poor motility (its ability to swim towards the egg), if donor sperm has low sperm count, or poor morphology (abnormal shape), or you have had previous failed IVF attempts combined with pre-implantation genetic diagnosis testing (PGD) or when sperm DNA fragmentation is high. 

In the laboratory, the embryologists will inject one sperm into each egg. In some cases, sperm may need to be surgically removed. 

Once the embryos have developed, the embryologist will select one to be transferred back to the womb during an embryo transfer procedure. The embryo(s) are loaded into a fine catheter & this is placed into the womb and the embryo(s) are expelled.