In vitro fertilisation (IVF) and sperm microinjection (ICSI)

In vitro fertilisation involves putting the male gametes (sperm) and female gametes (eggs) into contact so that fertilisation and initial embryo development can take place outside the mother's body.

There are two methods to produce the fertilisation:

• In vitro fertilisation (IVF): the spermatozoa collide with the oocytes in ideal conditions to make the fertilisation occur spontaneously.
• Sperm microinjection (ICSI): consists of intervening more actively in the fertilisation process, introducing a sperm cell inside each oocyte.

When fertilisation and development in vitro of the embryos obtained is achieved, the adequate number thereof is ed to be transferred to the uterus, in order to achieve an evolutionary pregnancy.

What is the general process of IVF/ICSI?

An ovary hormone stimulation treatment is d. This process has three objectives:

1. To block the physiological mechanisms controlling the ovarian cycle, in order to modify it according to the treatment needs.
2. To stimulate the development of several ovarian follicles.
3. To generate the final maturity of the oocytes with another hormone preparation.

When the desired follicle growth is obtained, the drug triggering the final maturity changes is administered and the follicle puncture is scheduled around 36 hours after. The oocytes are ed by puncturing the ovary through the vagina with ultrasound control and under anaesthesia.

The spermatozoa are generally obtained from a sperm sample. All the samples are subject to in-lab preparation, in order to the spermatozoa which will be used in the fertilisation techniques. If the fertilisation is obtained, the resulting embryos are classified according to their quality after several days of in-lab cultivation, in order to those with the greatest implantation probabilities to be transferred to the maternal uterus.

The embryo transfer is completely painless, does not anaesthesia and makes it necessary slightly to modify the subsequent life regime.

The evolutionary embryos not transferred to the uterus are cryopreserved and, if pregnancy is not achieved, they will be transferred to the patient before starting a new ovary stimulation.

What are the possibilities of success offered by IVF/ICSI?

It predominantly depends on the age of the patient and the number and quality of the embryos transferred. In general, the average pregnancy per cycle started is between 29-35%, although this percentage can vary between 10-40% according to the specific circumstances of the patients.

When are IVF and ICSI used?

They can be useful in the treatment of different fertility disorders:

• When the fallopian tubes are non-existent or severely injured.
• When semen quality is severely affected by a low sperm , poor mobility, or an abnormal incidence of morphological abnormalities.
• In cases of moderate or severe endometriosis, consisting in significant endometrial patches outside of the uterine cavity.
• In cases of abnormal ovulation that cannot be resolved by other treatments.
• In cases of immunological disorders with implications for reproduction.
• In cases of previous failure of fertility procedures.
• When the cause of infertility or sterility is unknown.
• In cases requiring Pre-implantation Genetic Diagnosis.
• Other situations.

Choosing the specific kind of in vitro fertilisation (conventional IVF or ICSI) in each case is a matter of considering the patient's history and the characteristics of their gametes, once these have been assessed in the laboratory. The final decision, therefore, is made just before the technique is carried out.

What are the relevant risks of IVF/ICSI?

The chances of multiple pregnancy (more than one foetus) and high-degree multiple pregnancy (more than two foetuses) increase as a result of the transfer of more than one embryo to the uterus.

Furthermore, there is a risk of ovarian hyperstimulation syndrome, which is an abnormal response to ovary stimulation treatment.

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