Ovulation-promoting drugs are often used during general ovulation induction, artificial insemination or IVF fertility treatments, so does the heavy use of these drugs affect ovarian function? The number of follicles in a woman is fixed at birth and no more new follicles are created after birth, and ovulation occurs in about 400-500 follicles over a lifetime. The process of follicular development is sequentially through resting follicles – early growing follicles – sinus follicles – mature follicles. Resting follicles are non-gonadotropin dependent and are influenced by genetic factors and local regulatory factors. It is only at the secondary follicle stage that they become hyposensitive to gonadotropins and gradually develop into sinus follicles, a process that takes 60 days and begins to become gonadotropin-dependent. Once the sinus follicle formation reaches 2 mm in diameter, this is the small follicle that we can see through ultrasound. After that, the granulosa cells increase significantly and their sensitivity to FSH increases further, and they continue to develop in dependence on FSH. It takes about 25 days to grow from 2mm to 18mm in diameter, the last 15 days being equivalent to the follicular phase of the menstrual cycle. If you want to retrieve only one egg or follicle, you do not need to give gonadotropins and only need ultrasound to monitor it at all times. However, for a higher success rate, FSH gonadotropins need to be given to obtain more follicles. These follicles that would have been atretic during the current ovulation cycle can be utilized. This is the purpose of the medication used for ovulation promotion. An important stage in the process of follicle maturation is the recruitment process, which occurs between days 1 and 4 of menstruation. In normal young women, there are about 20-30 follicles in the recruitment stage, called follicular clusters. Some follicles are sensitive to low FSH while others are not, so the sensitive follicles enter the next stage of growth and grow further to reach the criteria of mature follicles before they have a chance to become ovulatory, otherwise they are lost naturally. This treatment results in more follicles than in a natural ovulation cycle. Where do those immature follicles go? This brings us to follicular atresia. Atresia is actually a process that begins at 7 weeks of a woman’s fetal gestation and is in line with the natural pattern of oocyte annihilation. The follicles that enter a cycle are all in one batch, but the ones that eventually mature in a natural cycle are only one or two in most populations, with multiple being the exception. Just like the well-known large number of sperm, only one in a million is finally fertilized. The rest do not match well to the FSH level and enter the atresia stage accordingly. In other words, the process of administering ovulation medication only pulls the follicles that should have entered atresia back into the growth queue using the medication, rather than advancing all subsequent follicles, which is often misunderstood by many patients and does not actually affect subsequent follicles. As mentioned above, the resting follicles are non-gonadotropin dependent, i.e. they are in a sleepy phase so to speak, and do not respond. In contrast, the start of secondary follicles to follicle maturation generally involves a period of 3 months. Therefore, with the use of FSH Ken nutrient solution, it will not have an effect on the rest of the resting follicles, and with the metabolism of exogenous FSH, these follicles will still develop or occlude later according to their natural routine, and therefore will not affect ovarian function. The reason why many people who could not have children, but had children through IVF studies, became naturally pregnant with their second and third children is that it has the effect of treating ovarian pathology. Doctors of IVF patients usually advise IVF women to take more times and nurture together to save money. In IVF women with cytoplasmic replacement technique, it is even more important to take more times because of the high aging and poor quality of eggs in older women and only enough of them can increase the success rate.