The mean pregnancy rate after in vitro fertilisation is about 40% of couples undergoing treatment.
The particular conditions of each couple, the cause of the infertility as well as age can affect the increased or decreased likelihood of pregnancy.
In vitro fertilisation (IVF) is an assisted reproduction technique that involves retrieving the ovules from a patient, having undergone ovulation stimulation with hormonal therapy, and uniting one or more oocytes from the woman with the sperm of her partner in the laboratory setting.
The aim is therefore to improve fertility when there are certain problems that may obstruct this occurring naturally. Once the oocytes are fertilised, the resulting embryo or embryos are evaluated and transferred to the uterus. The number of embryos transferred varies depending on different parameters, but the maximum permitted legally is three.
In vitro fertilisation differs from in vivo fertilisation in that the fusion of the gametes occurs in the laboratory and not in the woman's body.
This technique is recommended as treatment for couples with different types of infertility, whether it is male or female related infertility.
Initially, it was used only in women with Fallopian tube blockage (tubular factor). At present, it is used in all cases of infertility due to problems associated with fertilisation or in the early stages of reproduction and in cases of unexplained infertility.
In vitro fertilisation indications:
Fallopian tube blockage
The woman undergoes ovarian stimulation which is monitored by means of ultrasound and hormonal analyses.
When ovulation occurs the follicle is punctured and the ovules retrieved. These will then be inseminated in the laboratory with sperm obtained from the semen specimen provided by partner.
From the embryos obtained, a maximum of 3 are transferred to the woman’s uterus. Embryo transfer is usually conducted on day 2 post-fertilisation, although in some cases the period of in vitro culture may be prolonged until the blastocyst stage is reached, 5-7 days.
In vitro fertilisation occurs in about 70% of the ovules inseminated. Thanks to intracytoplasmic sperm injection (ICSI) techniques, similar fertilisation rates are obtained even in patients with severe sperm abnormalities.
Embryos not transferred during the first IVF cycle can be preserved with embryo freezing techniques and those which develop adequately may be used later for cryo-transfers.