Physiological Intracytoplasmic Sperm Injection is a technique that allows the embryologist to select a mature sperm for ICSI based on binding to a natural occurring product that is found outside and inside of the egg.

Physiological intracytoplasmic sperm injection, also known as PICSI, is a laboratory procedure used to aid intracytoplasmic sperm injection (ICSI). It is carried out in addition to ICSI, and is used to select mature sperm cells to use in the ICSI process. 

PICSI is a non-invasive test and is carried out on the provided semen sample as an add-on or addition to the fertility treatment a patient is already undergoing. During the process, the sample will be placed with hyaluronic acid (HA). This is a natural compound found in the human body and sperm cells that are suitable for treatment will bind to it. These cells can then be identified and removed, to be used in a fertility treatment or frozen for later use.

As a non-invasive procedure performed on a semen sample, and as an additional step in the ICSI process, PICSI does not carry any additional known risks to either the patient or any children born to them. The only risks it could pose are those that also apply to ICSI. 

The risks most commonly associated with ICSI are:

  • Certain genetic and developmental defects (though these may have also been caused by underlying fertility issues, rather than the treatment itself)
  • The possibility that male children may inherit a father’s or donor’s infertility (though it may still be too early to know if this will be the case, as the oldest boys born from ICSI are only just starting to turn 30)


Where there is a clearly defined genetic cause of male infertility, particularly if it is associated with the Y chromosome, it is highly likely that male children will inherit infertility. Patients may wish to consider genetic testing before carrying on with fertility treatment, in order to avoid the possibility of passing on a low sperm count to male children (if a genetic cause for the low sperm count can be identified).

Fertility clinics will often offer PICSI because research has suggested that mature and structurally sound sperm cells can be identified through the process. However, it must also be noted that having the test carried out has not been shown to increase a patient’s chances of having a baby. 

Some studies have suggested that it does slightly lower the chances of a person having a miscarriage, but this was not the main aim of the research at the time. As such, the evidence can only be regarded as a secondary outcome of the process, and should therefore be treated as less reliable than if it had been the sought-after conclusion.

Currently, PICSI is outlined as a treatment add-on, or an additional option, to the ICSI IVF treatment process by the Human Fertilisation and Embryology Authority (HFEA). It is also listed as red in the HFEA traffic light system, owing to the fact that there is no evidence from randomised controlled trials (RCTs) that it improves the chances of having a baby for most fertility patients.