Assisted reproductive techniques

Almost 15% of couples of childbearing age have problems having children. The causes of sterility are varied:

• In women: There may be problems due to obstruction of the fallopian tubes, with ovulation, with the implantation of the zygote, etc.
• In men: It can produce few spermatozoa or that are defective or have little mobility, for example.

When there are infertility problems in the couple, medicine offers some alternatives to solve it:

Artificial insemination

When there is a problem for the sperm to reach the egg, either because they are scarce or have mobility problems, they are introduced through a cannula into the uterus, near the egg. This will produce fertilization in a natural way in the fallopian tubes.

The semen can be that of the woman's partner, but also, depending on the case, it can come from a semen bank.

In vitro fertilization

In this case, fertilization is carried out in the laboratory. In a Petri dish, eggs and sperm are brought together to be fertilized. The resulting zygote will later implant in  the woman's uterus.

The egg and sperm used can come from various sources:

• Fertilization of a woman's egg with her partner's sperm. For example, when a man's sperm have very little or no mobility, they cannot reach the egg.
• Fertilization of a woman's egg with sperm from an anonymous donor. For example, if the man is sterile and his sperm are not viable. Or if a woman does not have a partner or her partner is another woman, and she wants to become pregnant, she can also do so by in vitro fertilization or artificial insemination, with an anonymous sperm donor.
• Fertilization of an anonymous donor egg with sperm. If the woman does not produce viable eggs, IVF can be performed with eggs from an anonymous donor and sperm from her partner.

The embryo resulting from in vitro fertilization can then be implanted:

• In the uterus of the woman who has requested the treatment.
• In the womb of an anonymous woman. Although it is not legal in Spain, surrogate mothers lend their uterus for the embryo of the couple or person requesting treatment to develop.

In vitro fertilization consists of several stages:

1. Ovarian stimulation. Hormones are given that stimulate the production of various eggs.
2. Egg retrieval using a cannula.
3. Fertilization. Eggs and sperm are collected in a petri dish for fertilization to occur.
4. In vitro culture. The eggs fertilized and begin to divide discarded unfertilized.
5. Embryo transfer. Several zygotes are implanted in the woman's uterus to ensure that one reaches term.
6. Embryo freezing. The zygotes that are not used are frozen for use in the event that no zygotes have succeeded in implanting in the uterus and pregnancy occurs.

Micromanipulation techniques

If the sperm concentration is so low that in vitro fertilization cannot be produced or for some other reason there cannot be fertilization, the sperm can be introduced directly into the cytoplasm of the ovum.

Sperm and Egg Donation

As we have seen, if the eggs or sperm do not allow fertilization to occur, it is necessary to resort to a sperm or egg bank in which an anonymous person has donated their gametes. It is not a simple process. Being an egg donor requires medical treatment and a small surgery to extract it. Being a sperm donor is easier, but only those people who pass rigorous medical controls are admitted as donors, of eggs or sperm.

Although these assisted reproductive techniques are now very normal, it was not until 1978 that Louise Brown, the first “test tube girl”, was born. Since then, 6,000,000 children have been born using these techniques.

Although assisted reproduction has brought children and happiness to couples who wanted to have them, it has raised and continues to raise debates and controversies, by using fertilized eggs, moral, ethical, religious, philosophical and scientific.