ICSI

ICSI is a specialised fertilisation method in which the embryologist injects a single pre-selected sperm cell directly into a mature egg. The procedure is part of IVF treatment and may be recommended when the sperm cell has difficulty penetrating the egg naturally or when there is an increased risk that fertilisation may not occur.

The decision to use ICSI is made after assessing the results of both partners. The method has a specific role in the laboratory process and is not used automatically in every IVF procedure.

Duration

ICSI is performed in the embryology laboratory after egg retrieval and preparation of the mature eggs.

Stay at the Clinic

The method does not require any additional stay outside the time associated with the other stages of the IVF procedure.

Feeling

ICSI is performed entirely in the laboratory and is not associated with any additional sensation or discomfort for the patient.

A Precise Laboratory Technique with a Specific Medical Purpose

What Is ICSI?

What Does It Mean?

ICSI stands for intracytoplasmic sperm injection.
The procedure is performed using specialised microscopic and micromanipulation equipment.
One sperm cell is injected directly into the cytoplasm of a mature egg.

What Is Important to Know?

ICSI supports a specific stage of fertilisation.
The method overcomes the need for the sperm cell to penetrate the egg’s outer layers on its own.
Not every retrieved egg is mature and suitable for ICSI.

Individual Selection Based on Medical Indicators

When May ICSI Be Recommended?

1
When Semen Parameters Are Abnormal

ICSI may be considered in cases of very low sperm concentration, reduced motility, or pronounced abnormalities in sperm morphology.
The decision is based on more than one semen analysis parameter and on the overall medical information.
2
When Sperm Have Been Surgically Retrieved

The method is commonly used when sperm cells have been obtained directly from the testis or epididymis through Micro-TESE, TESE, MESA, or another procedure.
This may be necessary when sperm are absent from the ejaculate, when there is an obstruction of the reproductive ducts, or when spermatogenesis is severely impaired.
3
After a Previous Low Fertilisation Rate

ICSI may be recommended when conventional IVF in a previous cycle resulted in no fertilisation or fertilisation of only a small proportion of mature eggs.
Before the next attempt, we review the maturity of the eggs, semen parameters, and embryo development.
4
For Certain Laboratory Indications

The method may also be used when fertilising thawed eggs or in connection with certain preimplantation genetic testing procedures.
The decision depends on the laboratory protocol and the individual treatment plan.

How Do We Determine Whether ICSI Is Appropriate?

The decision begins with an assessment of reproductive history, semen analysis, ovarian reserve, age, and the results of previous procedures.

We take into account the number and maturity of the eggs, the embryologist’s observations, and the way embryos developed in previous cycles.

In cases of severe male factor infertility, we may recommend consultation with a urologist, andrologist, or medical geneticist.

The decision is made for the specific treatment cycle and is reassessed before each subsequent procedure.

How Are the Cells Prepared?

After egg retrieval, the cells surrounding the eggs are carefully removed so that their maturity can be assessed.

Only mature eggs can be injected, so their number may be lower than the total number retrieved during the procedure.

The semen sample is processed, and the embryologist selects sperm cells according to characteristics visible under the microscope, including their movement and shape.

This assessment is not a genetic test and does not provide complete information about the DNA or chromosomes.

Fertilisation, Development and Realistic Expectations

What Outcomes Can Be Expected?

The number of eggs retrieved during egg collection is not the same as the number of mature eggs. Not every mature egg is fertilised, and not every fertilised egg develops into an embryo suitable for transfer or freezing.

ICSI facilitates the sperm cell’s entry into the egg, but it cannot influence all subsequent processes.

The quality of the eggs and sperm, age, the genetic characteristics of the embryo, and the conditions for implantation all play an important role.

What Are the Limitations and Risks?

An individual egg may be damaged during preparation or injection.
Some or all mature eggs may fail to fertilise.
Embryo development may stop before the following stages.
In cases of severe male factor infertility, additional genetic assessment may be recommended.

What Are Realistic Expectations?

ICSI provides greater control over a specific stage of fertilisation, but it does not guarantee that an embryo will develop.
The percentage of fertilised eggs does not equal the probability of pregnancy or live birth.
The outcome depends on the quality of the eggs and sperm cells and on embryo development.
The method is recommended only when there is a specific medical or laboratory indication.

Frequently Asked Questions

ICSI is not a separate treatment from IVF. It is a laboratory method that may be used as part of an IVF procedure. The difference lies in the way the sperm reaches and fertilises the egg.
No. Before ICSI, the embryologist assesses the maturity of each egg. Only eggs that have reached the required stage of maturity are injected.
The embryologist selects a sperm cell based on characteristics that can be observed under the microscope, such as movement and morphology. Additional laboratory methods may be used when medically indicated.
No. The method facilitates the sperm cell’s entry into the egg, but it cannot guarantee that normal fertilisation will occur or that a suitable embryo will develop.
The fertilisation check is usually performed the following day. The team will inform you of the result and the next stages of embryo monitoring.
ICSI supports fertilisation but does not automatically improve the quality of the eggs, sperm, or resulting embryos. Embryo development depends on many biological factors.
Yes. ICSI can be performed using frozen and subsequently thawed semen when suitable sperm cells are identified after laboratory processing.
If fertilisation does not occur, the medical and embryology team will review egg maturity, semen sample quality, and observations from the procedure. This analysis is then discussed when planning a future treatment cycle.

ICSI

Duration

Stay at the Clinic

Feeling

A Precise Laboratory Technique with a Specific Medical Purpose

What Is ICSI?

What Does It Mean?

What Is Important to Know?

Individual Selection Based on Medical Indicators

When May ICSI Be Recommended?

When Semen Parameters Are Abnormal

When Sperm Have Been Surgically Retrieved

After a Previous Low Fertilisation Rate

For Certain Laboratory Indications

What Is the Difference Compared with Conventional IVF?

Is ICSI Necessary for Every Procedure?

The Faces of Hope

Dr. Petra Makedonova

Dr. Dimitar Cvetkov, MD

Dr. Maya Popova

How Do We Determine Whether ICSI Is Appropriate?

How Are the Cells Prepared?

Preparation, Micromanipulation and Follow-Up

How Is ICSI Performed in the Laboratory?

What Happens During the Procedure?

What Happens After ICSI?

Fertilisation, Development and Realistic Expectations

What Outcomes Can Be Expected?

What Are the Limitations and Risks?

What Are Realistic Expectations?

Frequently Asked Questions

Procedures

PICSI

ZyMot

PGT-A

News

Everything You Need to Know About Endometriosis: Symptoms, Diagnosis, and Treatment

Causes of Infertility

Contact form