In vitro fertilization was carried out for the first time in 1978 and is the procedure from which the
rest of the assisted fertilization treatments evolved. Since then and thanks to its implementation, thousands
of healthy babies were born.
Its creators based their research on the fact that for a pregnancy to take place it is not enough for the
oocytes and the sperm to be normal, it is essential for all the conditions to be adequate for the 'union' to
take place normally. This 'union' is, precisely, what is known as fertilization and, many times, it is because
of obstructions of the Fallopian tubes or other factors that prevent this union from happening that
pregnancies fail.
In vitro fertilization consists in making it possible for the oocyte and the sperm to join outside of
the female body in ideal conditions generated in a laboratory that allow an optimum follow up of the
process. Around the 14th day of the menstrual cycle, one or more oocytes are collected and placed in a glass
dish (vitro means glass in Latin) together with a sufficient amount of sperms that move about by themselves
in the same way that they do in women's wombs. This way, each of the treated oocytes has the faculty of
being penetrated by a spermatozoid. These unions will produce one or more embryos that will be transferred
to the uterus by means of a catheter; this procedure is very simple and not cruel at all.
Thanks to this technique, some couples with low chances of achieving a natural pregnancy, with no more than
1% of probabilities, may raise their chances up to 25% for each attempt. This places them at the same level
of those who do not have any reproductive disorders, whose chances for achieving a natural pregnancy are
between 20% and 30% for each attempt. The chances for success are cumulative, so that an
in vitro
fertilization treatment that consists of four successive attempts may raise the chances up to 70%.
The most important factors that determine the chances for a successful pregnancy are the woman' s age, the
quality of the collected oocytes, the quality of the sperm, the causes of the infertility and the number
of embryos transferred.