In vitro fertilisation (IVF)
The fusion of the masculine and feminine gametes generate the first cell of the life of a new human being. When this biological process doesn’t happen naturally, it is necessary to use in vitro fertilisation. This assisted reproductive treatment, where the embryologist joins the eggs and the sperm cells in the laboratory by selecting subsequently the embryo with greatest potential for its transfer in the maternal uterus and capable of producing a pregnancy.
This treatment, known by its acronym IVF, can be carried out with two different procedures. The conventional, leaving the egg and the sperm cell join spontaneously; or by means of a sperm microinjection or ICSI: When the sperm is of low quality and the fertilisation is done by injecting a single sperm in each egg.
Next steps in IVF
- Ovarian hyper-stimulation of the donor. By means of individualised medicine, depending on the characteristics of each patient, we manage to stimulate the ovaries by following strict transvaginal ultrasounds and analytic controls. The treatment consists of two parts differentiated by the type of drugs administered. In the first part of the treatment, exogenous menstrual cycle hormones (FSH and LH) are administered to cause a development of multiple follicles. In the second part, the patient is injected with the hCG hormone, about 36 hours before the follicular puncture, to induce ovulation.
- Follicular puncture. It is a simple, painless and quick intervention (with sedation) used to extract the follicular content where the eggs are located. Our gynaecologists program the follicular puncture in the operating room when the ovaries have mature follicles. This procedure, as we have already stated, is done under sedation. Egg retrieval takes between 15 and 30 minutes, depending on the number of follicles and the needle aspiration is controlled with a vaginal ultrasound.Once the process is over, our patients need to remain in hospital for about 12 to 24 hours in order to minimise the risks inherent to the technique. There is a nursing service supporting the patient to any need. This is because our Unit is located in one of the best hospitals in the Valencian Community and therefore we have a hospital environment.
- Oocyte count in the laboratory. The follicular liquid is sent to the laboratory so that the embryologists identifies with the use of a microscope the oocytes obtained from the puncture. They are subsequently isolated and classified in their maturation state.
- Capacitation of the spermatozoa. While the oocytes are being classified, the semen sample is being collected, either from the partner or the donor, for its capacitation. We select those spermatozoa with greatest fertilisation potential.
Our Andrology laboratory prepares the semen samples to use. In case we need semen from the donor, all the samples from our bank are from donors of legal age and anonymous. The samples are selected according to the blood type and the phenotypic characteristics of the person requesting it. They are perfectly studied, meeting the current legal standards of the Ministry of Health, to rule out any congenital or genetic diseases or any sexually transmitted disease.
- Fertilisation. Once we have the eggs and the spermatozoa with the greatest fertilisation potential, the fusion of gametes is carried out. This process is done via conventional IVF. It consists on placing an egg in the culture plate together with a high number of spermatozoa so that the one with the greatest potential fertilises the egg. Egg insemination can also be done through intracytoplasmic sperm injection (ICSI), a procedure in which a single sperm, previously selected, is injected directly into the cytoplasm of an egg.
- Incubator culture in Time-lapse. The embryos are kept in culture inside our Time-lapse incubators at a temperature of 37ºC and gas concentration and humidity similar to the human body. Our embryologists control the embryos cell development for a maximum period of 5 days and select the ones with higher quality and evolutionary potential so that, after being transferred to the mother’s uterus, a pregnancy is achieved. After the 3rd day, the obtained embryos can be transferred, although we think that the transfer in the 5th day (blastocyst phase) will give better results as the day of the transfer we will have a better selection and a better synchrony with the endometrium.Time-lapse technology allows to control the development of the embryos minute by minute by taking photographs. It allows us to make a more stable incubation and a better selection of the embryos to transfer.
- Embryo transfer. This step does not require sedation. It is a painless process where our gynaecologists transfer the embryo or embryos using a thin catheter and under ultrasound control. This allows them to see the most suitable area of the uterus to deposit them.
- Prognosis. After 12 or 14 days of the transfer, it is time to confirm if the patient is pregnant. Having a blood test done will confirm it.
- Vitrification. It’s the process of freezing the remaining embryos at a high-speed with cryoprotectant substances. The culture temperature goes from 37ºC to a cryopreservation temperature of -196ºC, preserving them in liquid nitrogen as long as desired and keeping the cells intact for later use.
The higher number of eggs and younger age, a better chance there is to obtain viable embryos and, therefore, achieve reproductive success. However, the most important thing is the quality (both of the egg and the spermatozoa), if the quality is not good, we won’t be able to conceive even if we extract many of them during puncture. In addition, not all eggs obtained manage to successfully fertilise. For this reason, it is important to obtain a good number of quality eggs and a large number of viable embryos that can be vitrified to be used in later cycles if you wish to have more children and, therefore, repeat all the process again.
The success of in vitro fertilisation depends to a large extent on the women’s age, the number and quality of the eggs obtained, the semen sample and the development of the embryos. In general, the pregnancy rate per cycle is between a 40% and 65%, although in patients under the age of 32, this percentage can be of 70% in three cycles.