Sperm Microinjection (ICSI)

What is ICSI?

Sperm microinjection is a highly sophisticated technique that consists of introducing a sperm inside an egg with a very fine needle.

When is this technique used?

CSI can be used when the patient has very few viable sperm, as only one sperm is needed for each egg. Couples who have previously been unsuccessful with IVF, who have to rely on sperm from the epididymis or the testicles, or who are going to undergo a pre-implantation genetic diagnosis can also try ICSI.

The technique signifies a fantastic advance in resolving male infertility problems, as it promotes success using semen with a very low sperm count, and even sperm taken from the epididymis or the testicles.

Difference IVF - ICSI

The pre and post treatment for ICSI is the same as IVF. The only difference is that the cumulus cells surrounding the eggs must be removed beforehand to facilitate the microinjection process.

Ovarian Stimulation

Carried out to ensure the best possible chance of success, by collecting more than the single egg produced naturally in each menstruation cycle. We use hormonal drugs, and monitor their progress meticulously with ecographies and blood testing (fasting is not necessary). The complete treatment is very quick, between 8 and 12 days.

Egg Collection

Carried out with a vaginal ecography in our surgery and under general anaesthetic. The process takes 15 to 20 minutes.

Preparation of the sperm

The male provides the centre with a sperm sample which is then processed in our laboratory in order to obtain the highest possible quantity of mobile sperm.


4 to 6 hours after the eggs have been extracted, they are placed with the sperm in an appropriate culture medium.

Observing the fertilisation process

16 to 19 hours after the insemination we test how many eggs have been fertilised. These are then separated and incubated in a culture medium that provides the best possible conditions for development. The eggs usually remain for 2 to 5 days in the incubator, and are then ready to be transferred to the uterus.

Embryonic transplantation

Carried out via the vagina, through the cervix opening into the uterus. The process is painless and requires no anaesthetic, and is done using a fine flexible tube. The most opportune moment for transplantation varies for each patient, for which it is imperative to consider the characteristics of each case. Our embryologists advise ideally between the second and sixth day after extracting and fertilising the eggs. The number of embryos transplanted is determined according to several factors, such as the desires of the patient, the history of infertility and its causes, and the patient’s age. Spanish law allows a maximum of 3 eggs per cycle.

Did you know...

… treatments for assisted reproduction are not unnatural. The natural course of pregnancy is not altered, and the only aid we give is to restore fertility, by assisting the process of unifying the egg and the sperm so they can create an embryo in the same way it would form in the mother’s uterus.