What hormones are used in IVF?

In a normal standard IVF, there are four different types of hormones that we are going to use. All these hormones can either be produced as recombinant hormones, so that means there is a culture of cells that produce a hormone that is biologically identical to the ones that the woman produces.  Sometimes, there are these hormones that can be obtained from biological products, either the urine of a menopausal woman or the placenta. These tissues are processed, and we obtain these hormones that are used for later stimulation of the ovaries. These are basically the hormones that are used for stimulation and inducing and triggering ovulation.

Other types of drugs that are also used are the GnRH agonist and GnRH antagonist. These are the drugs that are used to block natural ovulation. When we do a  normal IVF,  we want the patient not to ovulate until we think she’s ready for the egg collection, so we can get a good number of mature eggs. Therefore, for a few days, patients may have to take two different injections at the same time. One injection is going to keep stimulating the ovaries, the other injection is going to block the natural ovulation. These are drugs that are synthetical, artificial, and they are focused on preventing the patient from ovulating.

Then there is a fourth type of drug is progesterone that is usually started after the egg collection.  The progesterone that we now work with is natural micronized progesterone, so it is the same as the natural progesterone produced by the ovaries.  In this sense, they have no risk, and progesterone is useful because it’s going to prepare the endometrium to allow the implantation of the embryos.

To sum up, we have 4 different types of hormones. Hormones that are going to stimulate the ovaries,  recombinant FSH, recombinant hMG, LH, or biological hMG. We are going to use drugs to block the ovulation with a GnRH agonist or antagonist.  We are going to use drugs to trigger the ovulation with hCG, usually recombinant hCG, and also progesterone to prepare the endometrium, which is a natural micronized progesterone to prepare the endometrium for the embryo implantation.

Before we start talking about the hormones for IVF, I have to say a few words about the physiology of a female’s body. The development of follicles and oocytes starts around two previous cycles before menstruation and this part of oocyte development is called Hormonal independent. So, it is going on independently on medicines, which can be used during ovarian stimulation. At the beginning of the menstrual cycle, we have a cohort of follicles who are ready to grow up, but in a natural cycle, only one of them will grow up. FSH [follicle stimulating hormone] is a hormone produced by hypophysis in the head – inside the head, and it starts to affect the ovaries and the follicles start to grow up at the beginning of the cycle, and these growing follicles produce estrogens which are necessary to for endometrial growth. And at the middle of the cycle, hypophysis, once again the head produces a high dose of LH and this LH surge will lead to ovulation. Former follicles become corpus luteum and start producing progesterone.

Some of the most used medication in Assisted Reproduction Treatment are gonadotropins or oral contraceptive pills, clomid concentrate, GnRH analogues, progesterone and estrogens. Of all of them  gonadotropins and GnRH analogues that we use during ovarian stimulation, oral contraceptive pill before starting the cycle and the progesterone before carrying out an embryo transfer.

IVF is a process in which the first stage starts with ovarian stimulation. To stimulate the ovaries, we need hormones so you can understand that hormones play a very important role in IVF.

The basic hormones that are used are FSH and LH, which are called gonadotrophins. These can be either synthetic created in the laboratory or even coming from, for example, urine of menopausal women. They work similarly, mimicking a natural cycle, and they have the same role that FSH and LH have in reproductive medicine. There are other hormones as well, which are called GnRH analogues or GnRH antagonists. Depending on the protocol that we choose, they suppress the ovaries and down-regulate them so that you can then stimulate them, they may stop ovulation, which is very important because, in the old times, there was a lot of premature ovulation that was destroying the cycle. There was a lot of cancellations, but nowadays especially, with the GnRH antagonists, this is something that is prevented, and the ovulation only happens after triggering the follicles to release the eggs. This is another hormone that is used in IVF, it can be a GnRH analogue again, or it can be beta HCG, which actually helps in releasing the eggs, and it acts the same way as LH in a natural cycle.

Finally, before embryo transfer, estrogen and progesterone are very important. Estrogen primes the endometrium so that it can increase the thickness to accept an embryo. Progesterone is a very important hormone as well, because, in a normal spontaneous cycle, it is created and produced by the body. In IVF, there is no corpus luteum to produce this hormone, so we need external administration, so this progesterone can be given either through the vagina or through the mouth subcutaneously or even intramuscularly, all these hormones are very important, and they need to be used at the right doses and the right timings during an IVF. The whole plan behind all this is to mimic reality, to mimic what is happening in a natural cycle.

In the IVF we use many hormones but in any case we use them in order to try to mimic human female nature – it’s not that we give strange hormones – we use hormones that are the same in the woman’s body.
The first hormone used in order to stimulate the ovaries is a FSH. Every woman has FSH, the only difference that we give it in larger concentrations. We also use LH – another natural hormone that we give it also for the stimulation of the ovaries. Then we give the antagonists or the agonists – these are another category of hormones that help us program our cycle, help us treat the ovaries in order not to lose all the eggs and then there are some hormones that they do what we say the triggering – they help us ovulate the ovary in order to take the eggs.
Then for the second stage of an IVF cycle of course there are other hormones that prepare the endometrium and this is the estradiol, the progesterone. I repeat all these are hormones of a woman’s body so they are not strange hormones which help make a nice endometrium in order to receive the embryo transfer and the nice blastocyst in order to have the pregnancy.