By Laura Garrido BSc, MSc (embryologist), Susana Cortés Gallego BSc, PhD (senior embryologist) and Aitziber Domingo Bilbao BSc, MSc (embryologist).
Last Update: 05/14/2014

Intracytoplasmic Sperm Injection (ICSI) is a type of In Vitro Fertilization that is used quite often to fertilize the oocytes in the lab with viable spermatozoa.

In the past, embryologists used the conventional IVF method to fertilize the egg, which resembles the natural process to a larger extent. The eggs and sperm are brought together for a few hours, until the union between them occurred without the intervention of the specialist. But nowadays, ICSI is becoming the first option, even in cases where the benefits are unclear.

ICSI has a series of indications, though. In fact, the pregnancy success rates of ICSI are higher than those of conventional or traditional IVF, especially in cases of severe male factor infertility.

Indications of ICSI

The indications of Intracytoplasmic Sperm Injection (ICSI) can be classified into two groups: male fertility and female fertility problems. Let’s see the most common causes of infertility in men and women leading to the use of ICSI.

Male fertility problems

ICSI is an assisted reproductive technique used to overcome the following male infertility problems:

Female fertility problems

On the other hand, ICSI might be recommended in the following situations of female infertility:

  • If a low number of oocytes is obtained after follicular puncture or egg retrieval, or if the zona pellucida is very thick after oocyte retrieval, or in cases of poor egg quality.

 An alternative to conventional IVF

  • Repeated failure to achieve pregnancy after several cycles of conventional in vitro fertilisation.
  • Egg fertilisation failure using conventional IVF.
  • Microinjection of unfertilised oocytes using conventional IVF.
  • In-vitro maturation of immature oocytes.
  • When a Preimplantation Genetic Diagnosis (PGD) is required in cases of couples with some genetic alteration or when it is necessary to know which ones are genetically normal embryos.
  • In cases of immune infertility with a low number of antisperm antibodies and after repeated failure of previous artificial insemination cycles, or in cases of immune infertility with a high number of antisperm antibodies.

FAQs from users

In which cases is ICSI used automatically?

By Susana Cortés Gallego BSc, PhD (senior embryologist).

ICSI or Intracytoplasmic Sperm Injection is a type of In Vitro Fertilization that is used to fertilize the egg cell. With ICSI, the sperm cell is selected and injected within each one of the eggs collected.

Unanimously recognized indications of ICSI include:

  • Severe male infertility: a single sperm per egg cell is enough
  • Previous fertilization failure using conventional IVF
  • Issues with the oocytes: poor-quality eggs may compromise sperm penetration into the egg cell
  • Techniques that involve isolating the egg from the cells that surround it (egg donation, preimplantation diagnosis…)

What are the advantages and disadvantages of ICSI over IVF?

By Aitziber Domingo Bilbao BSc, MSc (embryologist).

Both techniques are reproductive technologies, and as such, we cannot say that one is better than the other. Actually, it depends on the diagnosis of each couple. In the case of conventional IVF, we put the oocyte in contact with a determined concentration of sperm, so that the sperm itself fertilizes the egg, which resembles natural fertilization to a large extent. In many cases, sperm quality is altered, in which case using the sperm won’t be possible. In such situations, we use ICSI. It consists in microinjecting the sperm, which is subjectively selected by the embryologists, into the oocyte.

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Authors and contributors

 Laura Garrido
BSc, MSc
Embryologist
Bachelor's Degree in Biotechnology from the Pablo de Olavide University (UPO) of Seville, Spain. Master's Degree in Biotechnology of Human Assisted Reproduction from the University of Valencia (UV) and the Valencian Infertility Institute (IVI). Experience at IVF, andrology, and general analysis laboratories. Embryologist specialized in Assisted Reproduction. More information
 Susana Cortés Gallego
BSc, PhD
Senior Embryologist
Bachelor's Degree in Biological Sciences from the Complutense University of Madrid, and PhD in Comparative Animal Physiology from the Faculty of Biological Sciences. Extensive experience in the scientific field, and currently working as the coordinator of the laboratories of Clínica Tambre in Madrid, Spain. More information
License: 17980-M
 Aitziber Domingo Bilbao
BSc, MSc
Embryologist
Bachelor's Degree in Biology from the University of the Basque Country. Master's Degree in Human Assisted Reproduction from the Complutense University of Madrid, and Master's Degree in Biomedical Research from the University of the Basque Country. Wide experience as an Embryologist specialized in Assisted Procreation. More information
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