Most assisted reproduction treatments require ovarian stimulation although, in some cases, natural cycle IUI (with no drugs) may be preferred.
Follicular response is always monitored with ultrasound scans (and soemtimes by evaluation of hormonal levels as well) so as to:
- adjust the dosage of drugs
- determine the exact time of ovulation (accurate to the hour)
- modify treatment in cases of high or poor follicular response eg convert to IVF cycle, cancel cycle, etc.
This hormone acts on the hypothalamus causing an increased release of Gonadotropin-Releasing Hormone (GnRH), which, in turn, stimulates the pituitary gland to produce Folilcle-Stimulating Hormone (FSH) and Luteinizing Hormone (LH).
This results in mild ovarian stimulation.
Clomiphene citrate is commonly administered to patients with irregular cycles due Polycystic Ovary Syndrome (PCOS).
Ovulation is achieved in about 70 – 80% of the cycles.
It is administed orally on Days 2 or 3 of the cycle for 5 days, at a dose of 50 – 100 mg / day.
Gonadotropins act directly on the FSH and LH receptors within the ovaries, promoting follicular growth.
The use of gonadotropins leads to significantly higher pregnancy rates compared to clomiphene citrate, but they require experience and diligence.
Gonadotropins are administered subcutaneously at the beginning of the cycle and the dosage depends on the type of treatment, characteristics of the ovaries and whether they are associated with agonists or antagonists of GnRH.
Inhibitors prevent spontaneous ovulation during a stimulation cycle, thus allowing for better control of the cycle.
There are two major groups – the agonists and antagonists of GnRH. Agonists have been used for a longer time, but antagonists are becoming increasingly popular.
Human Chorionic Gonadotropin (hCG)
Ovulation occurs 34 – 36 hours after treatment with hCG.
Therefore, according to the expected timing of ovulation, intercourse or intrauterine insemination (IUI) may planned accordingly.
Progesterone is a hormone which prepares the endometrium for implantation and creates an ideal environment to later support the pregnancy.
All treatments include a progesterone supplement during the luteal phase and early pregnancy.
Short protocol with Antagonists
Stimulation with gonadotropins begins during the first days of menstruation.
GnRH antagonist is then added either on a predefined day of the cycle (Day 6) or with the appearance of at least one follicle 14 mm in diameter.