It is an IVF variant in which a single spermatozoa is injected directly in the oocyte to facilitate its fertilization, but there must be at least some viable spermatozoa. In those cases when there are no spermatozoa in the ejaculate, they may be obtained from the testes or the epididymis.
This procedure is an option in cases of poor quality gametes or in prior fertilization failures.
This technique has achieved high success rates and has solved many male infertility problems that had failed with the conventional IVF. The pregnancy rate per cycle is between 55 and 65 %, but in patients under 35 years of age it can reach more than 70 %.