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Caitlin Whyte (Host):  I have a friend who has been talking about freezing her eggs and she was like 24 years old. We also kind of make fun of her for it because it seems so wild to be so worried about that stuff at such a young age. But the older I get, the more I realize I don’t really know anything about how egg freezing works. Here to guide me and you through the fertility preservation process are our trusted doctors Molina Dayal and Maureen Schulte from SIRM St. Louis.

This is All Things Fertility. I’m your host Caitlin Whyte. Molina, tell us more, what is fertility preservation?

Molina Dayal, MD, MPH, FACOG (Guest):  Fertility preservation is a medical treatment where basically we are trying to assist women who want to try to protect against future infertility due to reproductive aging, or other causes. So, it’s just a way of preserving their fertility in time so that they could come back later should they encounter fertility issue and use these preserved tissues.

Host:  Maureen, tell us about the different types of fertility preservation available.

Maureen Schulte, MD, FACOG (Guest):  Oocyte cryopreservation commonly known as egg freezing is the most common fertility preservation method that people think about. But there are also sperm cryopreservation and embryo cryopreservation. Additionally, there’s ovarian tissue cryopreservation and that’s experimental and most commonly reserved for prepubertal girls who are undergoing gonadotoxic chemotherapy. So, chemotherapy that can affect their future childbearing.

Host:  Is there a difference Molina, in success between egg and embryo preservation?

Dr. Dayal:  Well if you had asked me that question about five years ago, my answer would be different than it is now. Over time, the ability for us to freeze eggs and successfully thaw them has improved significantly. And in fact, it was about eight years ago officially that there was a new method of freezing embryos and eggs called vitrification which is a rapid freezing technique as opposed to what we used to do called slow freezing. And with vitrification, the success rate of thawing eggs and thawing embryos is about the same. So the vast majority of eggs and embryos will survive the thaw, close to 90-95% of them. And then the ongoing pregnancy that occurs, the success rate is almost exactly the same as well. The difference between egg and embryos of course is that embryos are a combination of egg and sperm and so they are already to be transferred as soon as they are thawed whereas eggs have to be thawed, fertilized and the grown out to become an embryo and then they are transferred.

Host:  Got you. Maureen, who do you recommend undertakes fertility preservation?

Dr. Schulte:  Cancer patients who are facing gonadotoxic therapy, so therapy that will affect the gametes or egg and sperm and ability to reproduce in the future should undertake fertility preservation. Additionally, planned oocyte cryopreservation which is for women who desire to freeze their eggs at a certain point is an option for everybody. And this, I really would encourage women to think about if they are in their early to mid-30s and they are desiring children in the future, however, they are not in a place in their lives where they want to get pregnant currently. And the reason behind this is because of the age related fertility decline that affects women. We know that as women age, their fertility and egg reserve and egg quality decreases.

Host:  All right Molina, as a woman, here’s a question I probably don’t even want to know the answer to right now. But if I’m considering freezing my eggs, when should I do it?

Dr. Schulte:  Now.

Dr. Dayal:  Right immediately. I think the – medically speaking, the best time to freeze eggs oftentimes is before a woman is 35. The younger a woman is, the more likely it is to be – the whole process will be successful. And that’s because as Dr. Schulte was saying, age has a major impact on a woman’s fertility potential. So, as a woman ages, the quality of eggs will decline. So, the later and later a woman waits, the less likely the treatment might be unsuccessful. But it doesn’t mean that it will be unsuccessful. It just lessens the likelihood because of the quality. So whether a woman is 32, 35, 38 or even 40; they can all undertake fertility preservation, but the key is really the counseling part where it’s us really telling them okay well at the age of 40, you’re likely going to need to preserve more eggs than somebody who is at 30 in order to be successful.

And that’s because the proportion of eggs that are normal when a woman gets older is less. So like for instance, we oftentimes say that we want to get or have let’s say six or seven eggs available in order to attempt pregnancy one time. And that’s because if you have let’s say six eggs frozen, five thaw and survive, maybe even five fertilize, about a third of them will get to the point where we can use them and transfer them. So, now you are down to approximately two embryos. So, at the age of 30, it’s typically about two out of three embryos will be normal but at the age of 40, it’s one out of five. So, you may have two available, but you don’t know if they are going to be normal.

Host:  Well that kind of leads me to my next question. Maureen, how old is too old to freeze my eggs?

Dr. Schulte:  There’s not a time limit on oocyte cryopreservation as Molina was saying. So, you are never too old but the younger you are, the higher quality and quantity of oocytes you should have. Earlier, is always better. Okay because of the biological clock. And Molina explained it beautifully. I think our biggest frustration is when patients are not properly counseled and think that freezing ten eggs is going to result in ten embryos and ten chances at having a baby. And that’s not how it works. There is a rate of decline of your ovarian reserve as you age and so you might need to undertake multiple cycles of egg freezing as you get older. Whereas if you undergo an egg freezing cycle when you are 32; you might only need to do it once because your quality and quantity of eggs is higher.

Host:  So, how is this all done? Molina, tell us about the process of freezing your eggs.

Dr. Dayal:  The process of freezing eggs is basically going through an IVF or an in vitro fertilization cycle. So, it’s the exact same process as you do for a typical IVF. And essentially it will take two to three weeks to undertake the process. On the most basic level, the way I always explain things to patients is that there’s a certain number of eggs available every single month and one typically ovulates, and the others die away. What we do with the IVF process and then the egg freezing process is we try to recruit all of those eggs that are potentially available that month to grow. And that’s done with a variety of different medications. These are all injections that a woman has to take. They are typically two injections that are taken a day. One is to prevent ovulation from occurring and one is to stimulate these eggs or follicles to grow. At the end of lets say 10 to 14 days of what we call stimulation or stimulating these eggs, women undertake an egg retrieval process. And that’s all done with anesthesia. It done through the vagina. There are no stiches or incisions. And women tend not to remember anything, feel anything, hear anything and it only takes about 20 to 30 minutes. And it’s the day that we retrieve the eggs that they are frozen.

Host:  So, once you freeze your eggs, how much time do you have to use your eggs, your embryos, your sperm? Maureen, how long can those things be stored?

Dr. Schulte:  Indefinitely.

Host:  Really?

Dr. Schulte:  Yes. So, they are flash frozen in time, is how I explain it to patients. So, let’s say you freeze your eggs at age 32 and you come back to use them at 40. Those eggs, their genetic material is frozen in time at age 32. So, they’re going to contribute the genetic material of a 32 year old. So, they have a higher chance of being euploid or contributing to a euploid embryo or chromosomally normal embryo than let’s say an egg from a 40 year old woman. And yup, they can be stored indefinitely, and you can come back and use them at any time.

Host:  Would the issue then be putting a 32 year old egg into say a 50 year old body or something like that.

Dr. Schulte:  No. So, really, we know that as women age, pregnancy is a stressful event on women. So, as women age, if they have comorbidities, diabetes, hypertension, obesity; those are all going to make a pregnancy more difficult. However, if you are a healthy 40 year old, you could carry a pregnancy without a problem.

Host:  I did not know that.

Dr. Schulte:  So, it’s really the state of the mother yes, the contribution of the egg quality meaning the genetic contribution that they’re going to provide to the embryo is really what matters most as far as increasing your risk of miscarriage and having a chromosomally abnormal baby.

Dr. Dayal:  And in fact, it’s just like Dr. Schulte was saying. It’s not about the uterus or anything else. It’s really all about that egg. And that’s why this is such a powerful thing for women to do. Uteruses don’t age per se. But eggs do.

Host:  That’s incredible. I have a whole new lease on life. All right. So, Molina, wrapping up here. we’ve frozen the eggs; we know that they can live forever, I guess. What happens when you decide okay, I’m ready to have a baby. How does the thawing process work?

Dr. Dayal:  It’s actually a relatively simple process from a lab standpoint. Once a patient decides to go ahead and thaw these eggs, we literally thaw them which actually doesn’t take very much time at all. It only takes – it takes less than an hour to thaw eggs. And then we fertilize them with a procedure called ICSI, it stands for intracytoplasmic sperm injection. It’s a mouthful. But we basically take one sperm and directly inject that sperm into an egg in order to fertilize it. And then we do something called culture the embryo so that means that we are watching that embryo grow in a very special environment within the lab until they form what’s called a blastocyst which is a day five or a day six embryo and that’s more than 80 cells and it’s at that time that the embryo can be transferred. And basically during this entire process, before the thaw takes place, the woman actually goes through a special preparation process in order to make sure her uterus is ready and receptive for pregnancy.

Dr. Schulte:  I encourage everyone to consider oocyte cryopreservation. I think it’s a very empowering step that a woman can take if she knows that she wants to have genetic children in the future. And a lot of my patients have said that it has taken stress off of them because they are pursuing their career, or they haven’t met the right partner and so they can – their mind can be at ease knowing that they have frozen eggs and it kind of takes that stress off from the biological clock.

Dr. Dayal:  I 100% agree. I think if anybody out there can do it, they should. I mean I have been talking to my nieces about it who are in their 20s. I’ve been talking to anybody I can to say look if you don’t know what your future holds then please really consider doing that.

Host:  Well I learn so much every episode I sit down with you both. So, thank you so much for the information. That was of course our doctors, Molina Dayal and Maureen Schulte from SIRM St. Louis. To learn more about the team at SIRM St. Louis, or to schedule an appointment visit www.stlouisfertilitycenter.com. If you enjoyed this podcast, find more like it in our podcast library. And be sure to give us a like and a follow if you do. This has been All Things Fertility. I’m your host Caitlin Whyte. Thank you for joining us. And we’ll catch you next time.