By Cristina Mestre Ferrer BSc, MSc (embryologist).
Last Update: 05/23/2014

The ICSI process includes some steps from the in vitro fertilization (IVF) process. The only difference is the way in which oocyte insemination is performed.

The ICSI process step by step is as follows:

  • Controlled ovarian stimulation: a series of hormones are administered so that the woman’s ovaries produce more than one mature oocyte. Moreover, this hormonal supplement also helps controlling the exact date when the menstrual cycle will start.
  • Follicular puncture: also known as egg retrieval, it consists of removing the mature oocytes by means of follicular puncture guided by ultrasound.
  • Sperm collection and preparation: a lower amount of sperm than IVF is required for ICSI, since it will be the biologist who, by means of a microscope with a micromanipulation system, will choose the ideal spermatozoon. If there are too many spermatozoa in the sample, it is counterproductive because it makes it more difficult to choose the one which is going to be injected.
  • Oocyte insemination: the ideal sperm is chosen and then the ICSI process is conducted. The spermatozoon is inserted inside the oocyte with a needle.
  • Embryo culture: embryo development is evaluated and recorded.

About the ICSI process

  • Embryo transfer: it is usually performed on day 3 of embryo development, although it can also be done on day 5 if a PGD is required or in cases where previous failure has occurred.
  • Embryo freezing: if more than a single healthy embryo exists, they are frozen in order to be used in further treatments.

Authors and contributors

 Cristina Mestre Ferrer
BSc, MSc
Bachelor's Degree in Biological Sciences, Genetics & Human Reproduction from the University of Valencia (UV). Master's Degree in Biotechnology of Human Assisted Reproduction from the UV and the Valencian Infertility Institute (IVI). Embryologist at IVI Barcelona. More information