Under normal response; the balance between the risks of ovarian hyper-stimulation syndrome and receiving a good amount of embryos is between 10 and 14 oocytes. So if a person has about 15 follicles inside both ovaries altogether, it’s a normal response; between 10 and 14. But if somebody has a lot of follicles, many follicles like PCOS patients will use fewer doses of FSH, we will change the trigger, and we will use some methods to avoid complications. For poor responders, like we already said, we also have special options.
I think that all depends on what you’re aiming for. If your aspiration is to do a fresh embryo transfer, there’s some really good evidence from randomized control trials that the optimum is about 11 – if you’re aiming for a fresh embryo transfer. If you’re aiming to do pre-implantation genetic testing for monogenic disease or structural abnormalities – more the better in those circumstances because we’re going to exclude some of those embryos. Again it all depends on what we’re trying to aim for and individualize but there’s generally this concept of kind of more is better overall.
The normal amount of follicles which is comfortable, is somewhere between fifteen and twenty. That is what we get in young women, with normal ovarian reserves. Of course, most of our patients have a problem with ovarian reserves and it is not so common to have so many eggs at the retrieval. The number is not as important as the quality of those eggs. We can have a good number of eggs but the real thing is to have the best quality eggs. So when we join it together with the sperm , we can get a high quality embryo that is good enough to implant and impregnate a woman. It is not about the number, mostly about the quality of those eggs.
There is no normal number of follicles for stimulation. It will depend on the variant reserved and the response of the variant to the medication. However the idea is to get between 8 to 15 according to the ovarian reserve, response to the stimulation and the type of patient obviously.
