Fresh or Frozen: The difficult debate for IVF
The answer to this important question is that it depends on each woman’s individual case. Let's discuss:
Benefits for women over 40
If you fall into this age category, there is research pointing to the benefits of frozen embryo transfer (FET), instead of having a transfer on a fresh cycle.
The reason for this is that women of a slightly older age are more likely to need a higher doses of fertility medications to promote the ovaries to produce enough egg follicles for retrieval. The down-side of this process is that the medications may have an unfavourable effect on the endometrial lining, making implantation less likely.
By delaying the fresh transfer and waiting for a couple of months the fertility medications have time to properly leave a woman’s system. There is then a better chance that the FET will succeed, as the endometrial lining will behave the same way as it would have done on any natural menstrual cycle.
Fertility medications are known in many cases to cause increased growth in pre-existing fibroids or other parts of the endometrial tissue. By avoiding a fresh transfer it means a woman has some time to deal with the fibroid, which might otherwise affect the chances of implantation.
There is also the added benefit of stress reduction, when a woman is going for an FET she knows there is definitely a good quality embryo ready to transfer. With a fresh cycle, there is the torturous process of waiting to see if the follicles will respond to the medication, then hoping that a decent number of those eggs will fertilise and make it to at least day 3, but ideally day 5, so they are more likely to thrive and implant properly after transfer.
What are the chances I will lose an embryo during the thawing process?
Thankfully, the odds are extremely slim that you would lose an embryo as it thaws, unless it was very poor quality to begin with. The only time I've seen this happen in the last number of years was when a lady had a day 2 embryo frozen, in the hope that it would develop a bit more when it was thawed. Unfortunately, it didn’t work out, but it would be very unusual to see an embryo frozen that hasn’t reached at least day 3 of development. Day 5 embryos are considered more reliable and it’s very uncommon to hear of any problems with an embryo at that stage of development after it has thawed.
Since the invention of the egg vitrification process fifteen years ago, the risks to the health of the embryo have dropped dramatically because the egg is frozen so quickly and efficiently that damage to it’s cellular make-up is almost non-existent.
Researchers from Aberdeen University reviewed the data from eleven previous studies on fresh v’s frozen success rates, in over 37,000 women and found significantly reduced risk of haemorrhaging, low-birth weight babies and pre-term labour in those women having the FET cycles.
That’s not to say that every woman having IVF should avoid having a fresh cycle of IVF, but if you have had repeated failed IVF treatments or find that you require a high level of medication to elicit a response from your ovaries, then a FET cycle could make a big difference to your chances of success.
Jessica Bourke is a Natural Fertility Specialist, who deals with all aspects of reproductive health. Her clinical approach is based on evidence-based nutrition protocols, acupuncture treatment, and she also offers functional lab tests to support you on your journey to parenthood. She's a regular contributor to Irish media and co-author of the 'Guilt Free Gourmet' cook-book. As a Mum of two, Jessica understands the challenges of pregnancy and parenting. For more, visit jessicabourke.com.