Medications used during the sterility treatment and methods of assisted reproduction
Oestrogens and progestogens are the main female sex hormones. They are commonly produced in the ovaries. Oestrogens are formed throughout the entire cycle, progestogens only in the second half of the cycle, after ovulation. Their main role is to work together to prepare the endometrium for implantation of the embryo.
In the field of assisted reproduction, in some cases the combination of oestrogens and progestogens is used to prepare the endometrium before the transfer of frozen embryos (FET). Progestogens alone are sometimes used after ovulation to support the preparation of the endometrium for embryo implantation or in the early stages of pregnancy, but also later in pregnancy to prevent premature delivery. However, it is always used in IVF cycle after egg retrieval to ensure the quality of the endometrium. We prefer agents with the effect as close to the natural hormones as possible.
Oestrogens may be in the form of tablets (Estrimax, Estrofem) adhesive plaster, spray or gel. Progestogens are administered orally; vaginal administration (Utrogestan, Gynprodyl, Crinone, Lutinus), or intramuscular (Agolutin) or subcutaneous (Prolutex) injections are more advantageous.
Ovulation in infertility treatment is often induced by antiestrogens (Clostilbegyt tbl, Tamoxifen tbl.). Their functioning is based on making use of feedback between oestrogens and gonadotropic hormones. Antiestrogens bind to oestrogen receptors and thereby induce production of gonadotropic hormones. They are always administered for a few days in the first half of the cycle.
To stimulate ovulation we use gonadotrophic hormones (gonadotrophins, GTH). They are formed naturally in the pituitary gland (hypophysis) and regulate the ovarian activity. GTH include the follicle-stimulating hormone (FSH) whose task is the growth of follicles, and luteinizing hormone (LH)whose task is maturation of follicles and induction of ovulation. Human chorionic gonadotrophin (HCG) is produced only during pregnancy by trophoblast and later by placenta. Detection of this hormone in blood or urine is used as a pregnancy test. For its structural similarity to LH it is used and produced, among other things, to trigger (start) ovulation (Pregnyl inj., Ovitrelle inj.).
We distinguish medications with only FSH effect, with only LH effect and with combined FSH + LH effect. Both types of products are used. Opinions on whether or when to use the product with a combined effect are not uniform. According to the method of production we distinguish the urinary-derived products, highly purified urinary-derived products and recombinant products.
The urinary-derived medicinal products have been on the market for the longest time, they always contain a certain amount of impurities and their effects are not completely constant (Merional amp., Menopur amp., Fostimon amp.).
Recombinant medicinal products are newer; they are produced by genetic engineering. They do not contain any impurities and the active substance content varies less than in urinary preparations. (Puregon Pen, Elonva inj., Gonal F Pen, Bemfola inj., Ovaleap Pen).
All gonadotrophin stimulation medications are applied subcutaneously by a thin needle and are therefore intended for self-administration. Most patients can do it without problems.
We use either small doses of gonadotrophins to induce maturation 1 or 2 follicles followed by IUI, or higher doses for controlled ovarian stimulation before IVF. We want to obtain more than one egg and consequently more than one embryo. This is achieved by administering gonadotrophins in relatively high doses. The dose depends on the results of hormonal profile, age, type of protocol, or weight, as the case may be.
In controlled hyperstimulation, it is not convenient that such substances are formed naturally in the woman’s body simultaneously with the administration of gonadotrophins. The thing is that it would be very difficult to harmonize their common action.
Therefore, in all ovarian stimulation protocols we use medicines that block the natural release of gonadotrophins from the hypophysis. They are called GnRh analogues. Under normal circumstances, the gonadotrophin releasing hormone (GnRh) is created in the part of brain called a hypothalamus. In the treatment, we do not use directly GnRh, but the substances originating from certain modifications of its molecule. We divide them into agonists and antagonists.
Shortly after their administration, agonists (Diphereline inj., Decapeptyl inj., Synarel spray) have the same effect as GnRH, and thus they increase the release of gonadotrophins from the pituitary gland, but later, thanks to their strong bonding, they block the pituitary receptors and inhibit the release of gonadotrophins. For this reason, agonists should be administered in the long term to make use of their blocking effect.
Antagonists (Cetrotide inj., Orgalutran inj.) have only a blocking effect; they can be therefore administered in the short term, during the stimulation itself.
There are certainly not all the preparations listed in our list. The reason for this is the fact that the situation in our market is constantly changing. The list will be continually updated.