Indeed, if you are too young, it’s not worth it if your ovarian reserve is good because the chances of needing them in the future are very low. If you’re 28 and your ovarian reserve is good, I wouldn’t recommend preserving your fertility at that point. I would recommend you to check your fertility yearly. The older you get, the more difficult it gets, so we usually recommend preserving your fertility between 35 and 38, which would be ideal or between 33 and 38 and until 40. After 40 years old, we do not recommend it. We accept it in specific selected cases up until 42 years old but only in cases where ovarian reserve is very good, and we expect to obtain a good number of oocytes and where the patient doesn’t want a pregnancy at that point.
My first question would be if you want to have children now. If you’re planning on having children, my first advice would be not to freeze eggs or embryos but to have a child ideally now naturally or through the help of fertility treatment. If you are not planning on having a child right away, of course, fertility preservation is the best option, and regarding survival rates on pregnancy rate in the future, we have very good results with vitrified eggs. Embryos survive the thawing process better.
In a younger patient, the survival rate that we have, at least in our centre where we use vitrification for freezing the embryos, the survival rate of embryos to the thawing process is around 98%. The survival rate for eggs to the thawing process is between 85 to 90%, so embryos survive better in the thawing process. From a biological point of view, maybe I would recommend freezing embryos. I think it’s important to check the details from a social and a personal point of view. Your partner today may not be your partner in the future, we’ve seen all situations, and once embryos are created, if you change a partner in the future, you won’t be able to use them. My advice would be unless you plan a pregnancy in the following year to preserve your eggs.
The treatment starts with menstruation, and the whole process lasts about two weeks if we do just one cycle. You do an ovarian stimulation with a subcutaneous injection that you inject yourself on your belly, and you do that for 8 to 12 days. Then we usually trigger the ovulation, and 2 days later, you come to the clinic for the pickup and then that’s it, so it’s around two weeks more or less.
The number of eggs that I recommend freezing depends on your age, and then again your expectations, and for example, the type of family you want to have. If you are 37 years old, we usually recommend obtaining between 12 or 15 mature eggs ideally, but this also depends on the type of family you want to have. I have patients who preserve 8 oocytes at 38 or 39, and they are positive that if it doesn’t work, it doesn’t work, and if it works, they only want to have one child. Therefore, this is a good result for them. I have patients who want to have a large family with 3 children, in that case, they will need more oocytes.
Regarding the number of cycles needed to preserve these oocytes, it depends on your ovarian reserve. As I’ve mentioned, most of the patients do cycle, but the older you get, the most likely you’ll need more oocytes, and therefore you will need more cycles. I would say between 12 and 15 mature oocytes is required.
We freeze mature oocytes because these are the ones that in the future these are the ones that will be inseminated, but in some cases, we can do what we call in vitro maturation of oocytes before they are preserved. During the ovarian cycle, they change their maturation stage. They go from immature or metaphase 1 to mature or metaphase 2.
The ones that are metaphase 2 are the ones that are capable of being fertilized by spermatozoa, therefore these are the ones that we need. If we inseminate a metaphase 1 or immature oocyte, it will never result in an embryo. However, we’ve seen that some of these metaphase 1 immature oocytes, if we leave them in an incubator for a certain time, they might change stage to metaphase 2 to mature oocytes. In those cases, what we call in vitro mature oocytes might be preserved in some cases.
The main exams that all fertility gynaecologists ask for is especially a vaginal ultrasound. We use vaginal ultrasound every day for almost all patients. We can see the shape of the uterus if there are any alterations in the uterus and check the ovaries. But also to check for cysts and other alterations such as endometriosis, for example. We also analyse the antral follicle count, which gives us a direct idea of your ovarian reserve. This is the main exam that we will ask you to do, we might ask you to do a blood test to check your AMH levels, which also gives us an idea of your ovarian reserve, your weight also gives us an idea of it and the regularity of your cycles, and then we will also ask you for basic exams to make sure you’re in good health, so a full blood count. We’ll have a look at sexually transmitted diseases.
Depending on the case, we will also ask you to do an exam to check if your tubes are opened, which is usually very difficult to check, called hysterosalpingography. It’s an exam where we introduce some liquid, and then we check if the tubes are open. Especially when you’re doing artificial insemination with your partner or if you have any history of infertility. Basically, for artificial insemination, we need to know that you’re in good health, that your ovarian reserve is okay and that your tubes are open.
This is something that I haven’t told you. When we usually preserve oocytes when we are talking about fertility preservation, the quality of oocytes doesn’t change with time, so that’s a good thing. The embryo quality, blastocyst, which is a day-5 embryo, doesn’t change with time once it’s frozen. Once embryos are vitrified or preserved, their quality remains the same, no matter the time passing, and that’s one of the reasons why vitrification is so good and useful if you preserve your fertility at 37, and you want to use your oocytes at 45. If you were using your own eggs or your own embryos at 45 years old, your chances of having a child will be near zero. However, if you have your preserved oocytes or embryos at 37, your chances of success at 40, 45 will be the same as you would have had when you were 37, which is the goal of the treatment.