The hormone preparations used
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IVF - hormone preparations
During an IVF treatment, hormones are used which otherwise occur naturally in the body of a woman.
The body's own hormones
GnRH (gonadotrophin releasing hormone) is made in the hypothalamus. It ensures production of LH and FSH;
Gonadotrophins are excreted by the hypofyse, located in the brain, near the hypothalamus. These hormones are carried by the blood to the reproductive organs;
- FSH (follicle stimulating hormone) triggers the development of follicles in the ovaries;
- LH (luteinising or ripening hormone) triggers ovulation;
- Oestrogen and progesterone are female hormones produced in the reproductive organs, each in a different phase of the menstrual cycle and in different quantities.
- hCG (human chorion gonadotrophin): pregnancy hormone. It is produced by the placenta and indirectly supports pregnancy. Presence of this hormone in a woman's blood is evidence that she is pregnant.
- hMG (human menopausal gonadotrophin) is found in the urine of women going through the menopause. It contains both LH and FSH in high doses.
IVF - hormone preparations
In IVF, various hormone preparations are used, both for the suppression of the natural cycle and the stimulation of the ovaries.
suppression of the natural cycle
- Agonists have the same effect as GnRH
GnRH, which is produced by the hypothalamus has a short half life, or in other words, breaks down quickly. When hormones where being isolated and identified around 1970, ways of imitating were sought in the form of anologs (agonists). Agonists are therefore GnRH anologs: hormones with the same effect, but with a longer half life.
In large doses, they ensure the increased secretion of FSH and LH, through which the natural cycle is suppressed, preventing ovulation. - Antagonists suppress the production of LH
More recent clinical developments have resulted in medications which prevent the production of LH. These are known as Antagonists.
These too have the effect of preventing ovulation, so that it can be triggered when desired as part of the stimulation phase of the treatment.
Stimulation of the ovaries
The ovaries are then stimulated either shortly afterwards or at the same time, with hormones which encourage production of FSH (and LH).
- Gonadotrophin fine preparations (hMG or rec-FSH) ensure the development of several follicles simultaneously. The administration of which is carried out under strict hormonal and ultrasound control, to avoid over stimulation.
- the hMG used during IVF treatment is produced from human urine from women going through the menopause. It is a combination of FSH and LH and when administered in the correct dose, has the same effect of (administered) FSH. It is however not available on the Belgian market at the moment.
- rec-FSH: a synthetic (recombinant) substitute for FSH.
Triggering ovulation
Every kind of stimulation treatment is concluded with an hCG injection. hCG or pregnancy hormone can be obtained from purified urine from pregnant women. Administration of the hormone leads to ovulation 36-42 hours later. (The same effect as LH).
supporting a pregnancy
Finally, any resulting pregnancy is given support:
- in most IVF cases via the administration of natural progesterone. This promotes the development of the endometrium (lining of the womb) and facilitates the implantation of the embryo;
- in some cases, the uterus is prepared for the arrival of a (thawed) embryo via the administration of oestrogen.