IVF
IN VITRO FERTILISATION
In IVF procedure ova are fertilised with sperm in laboratory conditions and embryos (fertilised ova) develop 2-5 days in an incubator. 1-2 embryos are selected to be transferred into uterus. The rest of embryos are frozen and transferred into uterus later. IVF procedure is comprised of three stages and lasts 30-50 days from the first day of administration of medications until the diagnosis of pregnancy.
Stages of IVF procedure:
1. Hormonal stimulation of ovaries
2. Puncture of ovaries and fertilisation of ova
3. Growing and transferring of embryos
A. Preparatory stage (hormonal stimulation of ovaries)
The objective of this preparatory stage is the stimulation of simultaneous development of several ova, or controlled superovulation. Nowadays controlled superovulation method uses gonadotropin-releasing hormone (GnRH) analogues or antagonists with menopausal or recombinant gonadotropins (FSH and LH). The final maturation of ovaries is affected by human chorionic gonadotropin (hCG).
B. Puncture of ovaries and fertilisation of ova
Ovaries are punctured 36-38 hours after hCG injection. The puncture of ovaries usually takes about 10-30 minutes and during the process ultrasound-guided needle is used to retrieve eggs from follicles. Mild anaesthetic is used for analgesia. After the puncture women are observed in the clinic for a few hours.
Men give semen at the same time as puncture is performed on women. Semen is processed to retrieve the most potent sperm cells. Upon IVF procedure ova are fertilised with sperm in test tube, i.e. in vitro conditions. In the event of severe male infertility the fertilisation of ova may use ICSI method. The fertilisation of ova is inspected 16 hours after the puncture. On the average, 70% of ova are fertilised in IVF/ICSI procedure.
C. Growing and transferring of embryos
Fertilised ova can be grown in incubator for up to 5 days, but usually two days are considered sufficient. Thereafter one or two 2-4-cellular embryos are selected to be transferred into uterus.
The principal criteria for selecting embryos concern their outer shape and the rate of cell division. Alternative option is to grow embryos for 5 days until blastocyst stage, which enables to select the most potent embryos for transfer into uterus. After the transfer women start pregnancy preserving treatment that lasts until the 8th week of pregnancy. Thereafter the pregnancy test and the ultrasound examination are performed. Ultrasound enables to see pregnancy already on the 28th day after transfer if the diameter of embryo is 10mm, and it is possible to observe the heart rate of the fetus.