Assisted Reproduction
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In Vitro Fertilisation
What is In Vitro Fertilisation?
IVF treatment is more complex than artificial insemination. It is used to reproduce the natural fertilisation process that occurs in the woman's body, but in a specialised laboratory. In this way, the patient´s eggs are fertilised in the laboratory using either the sperm from the husband / partner (homologous fertilisation) or donor (heterologous fertilization). After they are collected, the embryos are transferred into the patient´s uterus. It is necessary to go through a cycle of ovarian stimulation to obtain enough eggs and to ensure good embryo transfer.
In what cases is in vitro fertilisation used?
IVF treatments are used primarily in the following cases:
- As an alternative, when the patient has tried one or more treatments of artificial insemination, and no pregnancy has resulted
- Male infertility
- Blocked fallopian tubes
Procedure:
IVF is performed in several steps:
1. Evaluation
Before starting any treatment, the medical team will examine each couple and their reproductive state, in order to specialise the treatment.
2. Ovarian stimulation
Hormonal drugs (gonadotropin) are given to the patient to induce multiple ovulation (stimulated ovaries produce several mature eggs rather than just one). The patient is monitored using Ultrasound at all times. At this stage, hormone treatment is also given.
3. Removing eggs
The extraction is performed at the fertility clinic with the patient sedated and / or using a local anaesthetic, which allows them to remain conscious throughout the procedure. The total process takes about 30 minutes.
A transvaginal puncture is performed using ultrasound to guide the process, extracting all follicles in order to obtain as many eggs as possible. After a brief rest, the patient is ready to go home.
4. Insemination of eggs
Once obtained, the eggs are catalogued in the laboratory according to maturity. The mature ones are suitable for fertilisation. Simultaneously, the semen sample is obtained, which is prepared with the best and most mobile sperm. After aspiration, the eggs are inseminated with the sperm (a maximum of 3 eggs may be fertilised).
5. In Vitro Cultivation
The sperm and eggs are incubated together for 24 hours and are then evaluated to check whether fertilisation has been successful. This is confirmed by the appearance of 2 pro nuclei. The final objective is to transfer a maximum of 3 of the resulting embryos.
6. Embryo transfer
Once the embryos are cultivated, they are placed in the uterine cavity. This happens between the 2nd and 6th day after extracting the eggs. Most transfers are made into the uterus, which is a simple procedure that takes about 10 minutes, performed without anaesthesia and is very similar to an intrauterine insemination. In some cases the transfer can be made into the fallopian tubes. This procedure also takes place on an outpatient basis. A speculum is used to see the cervix, then the embryos, immersed in a culture, are transferred into a catheter (a long, thin sterile tube). This catheter is gently guided through the cervix and the contents placed in the uterine cavity. After the transfer, the patient is advised to rest and they will then receive further hormone treatment (progestogen) until the pregnancy is confirmed.
Possible Complications
- Ovarian hyper stimulation syndrome: The abdomen may become distended and the ovaries enlarged. Nausea, vomiting or abdominal pain may occur. Any patient with these symptoms within a week after the egg retrieval should contact their doctor.
- Vaginal bleeding: Light, painless bleeding may occur after follicular aspiration or after the transfer and stops within 24 hours. It usually comes from the uterus and does not affect the embryo transfer.
- Multiple Pregnancies: When obtaining and transferring more than one embryo there is the risk of multiple pregnancies.
- Follicular aspiration: All follicular aspiration carries two risks: bleeding and infection, although this rarely happens and can be easily treated.
- Abortion: Between 8 and 10% of all pregnancies end in spontaneous abortion. In the case of IVF, the rate ranges from 12 to 17%. This may be partly due to the fact that the average age of women who become pregnant through IVF is higher than that of women with a natural pregnancy and also that the very close monitoring of the patients means that pregnancies ending in an early abortion are detected, something that can remain undetected in natural pregnancies.
- Genetic or congenital defects are present in a proportion equal to the general population. In the case of pregnancies achieved by classical IVF methods, these risks are not higher or lower than in natural pregnancies.
Results
We use the frequency of pregnancy occurring after making the embryo transfer as an index to measure results of the treatment,. The probability of pregnancy is very high, between 25% and 35%, meaning that one in four embryo transfers results in pregnancy. These figures may vary depending on several factors, including the age of the patient.
The probability of pregnancy also increases with the number of cycles of treatment undertaken, so that after four cycles of IVF, the cumulative rate of pregnancies may reach 60%.
