In Vitro Fertilisation

In Vitro Fertilisation (or IVF as we shall refer to it hereafter) consists, broadly speaking, of combining sperm and eggs in a laboratory in order to bring about the fertilisation of the eggs. The resulting embryos are inserted into the uterus and then they only have to complete the implantation stage for there to be a pregnancy.

The first step is to stimulate ovulation in the woman so that she has more than one egg in the cycle in which the treatment will be carried out. This will require regular ultrasound scans to check the number and size of the developing follicles (the ovarian cysts which hold the eggs). Once the ultrasound shows that the follicles are ready, we will collect the eggs by puncturing the ovaries via the vagina, using ultrasound to guide the procedure, and aspirating the contents of the follicles. Once the eggs have been collected, the man is asked for a sperm sample and in a laboratory the sperm are added to the eggs to fertilise them. There are two possible fertilisation processes. There is what we call classical IVF which consists of leaving the sperm and eggs together so they fertilisation arises by itself. In some cases, however, it is necessary to carry out intracitoplasmatic sperm injection (or ICSI for short). This consists of actively introducing or microinjecting the sperm into each egg. Whichever technique is used it is possible to check which embryos have been fertilised after 24 hours. Two or three days after the eggs are collected, the fertilised embryos are reinserted into the uterus (limiting the number to avoid the risk of a multiple pregnancy). To carry out embryo transfer, as the procedure of reinserting the embryos into the uterus is known, we use a fine tube measuring a few millimetres which passes through the cervix, leaving the embryos at the back of the uterus cavity. We constantly check that we are placing the embryos in the right place using ultrasound to guide us. Just as we pointed out with regard to artificial insemination, this procedure is no more unpleasant than a typical gynaecological examination.

We have already said that the number of embryos transferred is limited to avoid the risks of a multiple pregnancy. Indeed, nowadays it is usual to transfer two embryos, reserving the transfer of three embryos (the maximum which should nowadays be transferred, and indeed the maximum allowed by law) to selected cases. If there is a larger number of embryos than the number chosen to be transferred to the uterus, the remaining embryos may be frozen to be used by the couple in subsequent cycles, whether a pregnancy does occur and the couple want another child some years later, or the procedure is not successful and they wish to try again.

Pregnancy rates for IVF are higher than 40% for each attempt and the risks of a multiple pregnancy are minimal. We can put this risk, according to our statistics, at 15% for a pregnancy with twins, and less than 1% for triplets.

And when is IVF suitable? The most typical use of IVF and the one for which the technique was developed is when there is an irregularity in the woman’s two Fallopian tubes or when they are even missing. Another typical use since the introduction of ICSI has been the case of very low sperm counts in the man’s ejaculate. Nowadays, ICSI allows us to bring about fertilisation in cases where the man has extremely few sperm. We can even consider fertilisation for men who have no sperm in their ejaculate but from whom we can collect some sperm directly from the testicle by carrying out a small biopsy. Just eleven years ago it was necessary in all of these cases to use semen from a donor if a child was wanted. ICSI also makes it possible to bring about fertilisation for men who have had a vasectomy. A biopsy is used to collect sperm directly from the testicle and ICSI is then carried out with them.

Other typical cases for IVF are endometriosis, which, due to the damage it causes to the Fallopian tubes and the ovaries, means that this technique has to be used, and where couples have not had a pregnancy after four cycles of artificial insemination. In these cases, in addition to bringing about a pregnancy, IVF often provides us with the real diagnosis for the couple by checking the condition of the eggs and the behaviour of the sperm and eggs when placed together. Finally, IVF allows us to use specific techniques, such as Pre-implantation Genetic Diagnosis, to detect genetic illnesses.