Human beings are the outcome of a happy encounter between a sperm and an egg. In natural reproduction, ejaculation sends millions of sperm into the vagina on a real obstacle race to reach the egg. The sperm travel from the vagina to the fallopian tubes, where they meet the egg. Out of millions of sperm, only one will be able to fertilise the egg by penetrating its membrane. Once it has managed this, the sperm loses it tail and fuses with the egg nucleus. This produces a reaction that hardens the egg membrane to prevent other sperm from entering. Sometimes, and this is becoming more common as women delay getting pregnant until later in life, this encounter is not so easy.
Artificial Insemination simply imitates the natural reproduction process, inside the uterus, making it easier for the sperm to reach the right place at the time when the ovulation takes place. Artificial Insemination is used when sperm have problems reaching the uterus, either because there is a blockage or because of low sperm count or quality. When Artificial Insemination is done with the partner’s sperm, it is known as Artificial Insemination with partner sperm (AIH). When we cannot obtain sufficient sperm from the partner, or when there is no male partner, we look for an anonymous donor. This is what we call Artificial Insemination with donor sperm (AID). This technique is relatively straightforward and gives very good results. However, sometimes things are not so easy and we have to turn to In Vitro Fertilisation.
In Vitro Fertilisation involves fertilising an egg with a sperm outside the uterus, in the laboratory. If the woman’s eggs are in good condition they are harvested and, using an extremely fine needle, a sperm is injected into each egg to fertilise it. This is what we call Intracytoplasmic Sperm Injection, or ICSI. Once it is fertilised, the egg becomes a pre-embryo and is placed in the uterus to continue developing. When we suspect that sperm may be damaged in some way, we need to see things close up so we can select the healthiest ones. This procedure is known as Intracytoplasmic Morphologically-selected Sperm Injection, or IMSI. The same as for Artificial Insemination, for In Vitro fertilisation, semen can be provided either by the partner or by an anonymous donor. It may be that the woman is not producing eggs or that her eggs are not fit for use, in this case, eggs of an anonymous donor can de used and, as before, they are fertilised with sperm from either her partner or a donor before being placed in the uterus to continue developing. With this technique, 6 out of every 10 women fulfill their dream of becoming a mother.