The follicle-stimulating hormone or FSH is a type of gonadotropic hormone secreted by the pituitary gland in men and women. In both cases, it regulates the reproductive cycle.
It is responsible for oestrogen secretion and its name “follicle-stimulating” comes from the function it performs in women: it triggers follicle development and growth within the follicles in the ovary until one follicle is fully mature.
For the assisted reproductive treatments, it is prescribed for ovulation induction in artificial insemination, in vitro fertilisation, or ICSI cycles with the aim of triggering follicle growth and development.
Medicaments containing FSH as a drug for assisted reproductive treatments are indicated in the following cases:
- Women suffering from polycystic ovary syndrome (PCOS)
- Previous ovulation induction failure using other medicaments
- Women with high blood plasma LH levels
The advantages of using FSH in order to increase the number of eggs produced are as follows:
- FSH, and especially recombinant FSH, has few side effects, since it is purer and contains no traces of urinary contaminants.
- It produces several homogenous follicles containing a large number of oocytes throughout each stimulation cycle.
- It is highly effective, since a low dose may be enough for performing a correct ovarian stimulation.
The disadvantages of using FSH for assisted reproductive treatments are as follows:
- If it is not correctly supervised by the gynaecologist, the dose administered may lead to ovarian hyperstimulation syndrome (OHSS)
- Multiple births: due to the development of more than one follicle, it may cause this type of pregnancy, especially in artificial insemination treatments.
- High economic cost: in particular, recombinant FSH is more expensive than urinary-derived FSH
Depending on origin, there are two types of FSH preparation as a medication. These types are mentioned hereafter:
Traditionally, this is how the largest amount of FSH is obtained. Urinary-derived FSH derives from the urine of menopausal women. Menopausal women no longer develop follicles, which mean they present high levels of FSH in their urine.
There are two types of urinary-derived FSH preparations:
- hMG (a.k.a. menotropin): human menopausal gonadotropin, which contains 75 IU FSH and 75 IU (international units) LH. These medications are known as Menopur and hMG-lepori.
- Highly purified urinary FSH: it contains FSH in its entirety, with only 0.1. IU LH.
Recombinant-derived FSH is obtained by means of genetic engineering. In this case, there is only presence of FSH (no traces of LH). These drugs are Gonal and Puregon.
There is also another medicine known as Pergoveris. It is a mixture of different gonadotropins, since it has 150 IU recombinant FSH and 75 IU recombinant LH.