The so-called Progynova is a drug whose active ingredient is estradiol valerate. In practice we can say that Progynova are tablets of estradiol, the female hormone par excellence, which can be administered orally and absorbed by the body.
Estradiol is naturally secreted by the follicle (the structure that forms in the ovary and houses the egg) during its growth. As the follicle increases in size, during the so-called first phase of the cycle, the level of estradiol increases in the bloodstream of the woman, generating multiple effects throughout the body.
In fact, this hormone is involved in the majority of female sexual characteristics and is ultimately responsible for the changes that women experience during the menstrual cycle, especially in the first phase of the cycle.
Once a woman ovulates, the second phase of the cycle begins. In this phase, the estradiol now secreted by the corpus luteum (structure that remains in the ovary after ovulation) is also important in controlling the cycle, now together with progesterone, which is fundamental in this phase.
In medicine it is possible to use drugs such as Progynova (Meriestra, Progyluton, Evopad...) on different occasions. For example, the symptoms of menopause are caused by the almost absence of estradiol during this period of the woman, so supplying this hormone externally will eliminate these symptoms. In fact, this is the main indication for these drugs.
In reproductive medicine, estradiol is used to simulate a menstrual cycle in a controlled manner. In the first phase of the cycle, only estradiol will be used and, subsequently, ovulation will be simulated by adding progesterone to estradiol.
This is usually done in the context of an embryo transfer where it is important to control the woman's cycle, both in intensity and time. For example, in a transfer of frozen embryos or in a donation of oocytes.
In this way, after the woman's menstruation, estradiol is prescribed (variable dose according to the patient's characteristics) simulating the first phase of the cycle, when the woman would be developing both follicles and endometrium. As the objective in this phase is usually to create the endometrium necessary to perform a good embryo transfer, this is usually controlled by ultrasound.
Sometimes, according to the data obtained, it is necessary to vary the doses of estradiol. Once the best possible endometrium has been obtained for the transfer (the treatment usually lasts around 14 days) the administration of progesterone begins, thus entering the second phase of the cycle.
The duration of this second phase is controlled by the medical team and will depend on the day of embryonic development in which it is desired to transfer and if appropriate the endometrial receptivity test. After this, the transfer is carried out according to the indications of the medical and biological team.