Zero for eight- WHY?
1 Replies
dh1965 - August 16

Dear Dr Smith (or other informed members),

My wife and I would be very grateful for your views as we try to understand another disappointing development (after about 3 years of trying to get pregnant, including 3 failed IUI's).

About 6 months ago, we had our first (unsuccessful) IVF attempt. At the time, 20+ eggs were extracted, which was a major relief as my wife has internal vericose veins and also abdominal surgery as an infant that made extraction through her abdomen risky. We were lucky and ended up with 8 very high quality embryos which were frozen for the next attempt.

After the normal preparation and anticipation, today was to be the 2nd attempt at implantation. Unfortunately, we were told that upon being thawed 7 of the 8 embryos did not survive and the 8th was of such poor quality that there was no sense trying.

After the first failed attempt, our doctor was quick to order a full set of blodd tests and high Natural Killer cells were identified. (My wife had an IVIG and took clexane before what was to be the attempt with FET). Could this have caused the embryos to not survive? Should we wonder if the clinic did something wrong? Or were we most likely just unlucky- again?

We have been going to a center that has a good reputation and we like the doctor a lot. Since today was quite an emotional day, we decided to delay the "de-brief" and future planning for a few days. Any insights as to what might have gone wrong (or what questions we should ask) would be very useful.

Thank you very much- this is an amazing resource and public service.


Dr Smith - August 17

The survival rate of frozen-thawed embryos depends on several factors: the "quality" of the embryos, the technique used for freezing and the technique used for thawing. Since you were informed that they were freezing high quality embryos, that leaves us with the other two factors.

Because of the relatively high number of embryos frozen, I going to assume that the embryos were frozen on Day 3 of development (between the 4 and 8-cell stage of development). Unfortunately, the technique used for freezing and thawing embryos at this stage can yield quite variable results (0-100% survival). This is not the first time I've heard of this kind of "nothing for transfer" situation and for this reason I do not freeze embryos at this stage. Instead, I prefer to freeze the embryos at the blastocyst stage. Only a fraction of the embryos will reach the blastocyst stage, but the ones that do are developmentally competent and quite hardy. The protocol for freezing and thawing blastocyst stage embryos is well established and this protocol yields less variable results compared to protocol used to freeze embryos on Day 3. Over several years of freezing and thawing blastocyst stage embryos, I have come to expect a >90% survival rate and a 40-50% pregnancy rate from FETs.

I think you need to ask your doctor why they don't wait until the embryos reach the blastocyst stage prior to freezing. If the response is that they have not had good results with freezing and thawing blastocysts and/or culturing embryos to the blastocyst stage, look for another program as this would imply that the lab is not up to date.

The presence of elevated NK cells, the infusion of IVIG or the use of Clexane (a low molecular weight heparin) would not have affected the survival of the embryos. However, had the embryos survived and been transferred, the IVIG would have helped prevent NK cell activation and the Clexane would have helped prevent any clotting problems during implantation or the pregnancy.



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