I have mentioned in previous posts that I would have transferred three or more embryos if they would have let me. I wanted as many opportunities for success as possible! My thinking at that time was a bit naive, however. I was only thinking about the success rates quoted and the probability of even one making it. I didn’t consider the extreme risk of high order multiples to me and to the unborn babies. I didn’t concern myself with the financial implications of having twins, triplets, or quads or the sheer logistics of managing that many infants. I never once thought about the likelihood of bedrest and babies being born premature if more than one of the embryos implanted. There are others pursuing fertility treatments that do think of these things and more, though, and there is a growing trend toward transferring single embryos.
There are plenty of success stories from women who have transferred one embryo and conceived. Most of the ones I have heard are due to only having one embryo that makes it to the necessary stage of development or because a small number of eggs are retrieved leading to fewer embryos available for transfer. When you delve into the issue further, though, there are a surprising number of women who opt to only transfer one even if they have a number of quality embryos available and even if their physician still recommends transferring two. These women are choosing single embryo transfers because they do not think they can manage multiples for one reason or another, because they are facing a high risk pregnancy even if pregnant with only one, because they are utilizing PGD and are choosing to transfer the healthiest embryo, or for a myriad of other reasons.
Many women who opt to transfer a single embryo do so only after learning of their PGD results. PGD improves the success of IVF and allows a couple to know that they are transferring a genetically “normal” embryo. When PGD is employed, couples also have the benefit of freezing embryos that are not initially transferred and knowing that those embryos are healthy should they elect to do another transfer down the road. If a couple does not opt to test the embryos prior to transfer the embryologist will typically select the two or three best developing embryos based on their educated assessment.
My husband and I did not use PGD and I do not know if the results would have made a difference in the number of embryos transferred. As the practice of transferring single embryos becomes more commonplace, though, we will get a better idea of the success rates associated with transferring only one and I image the decision will become much tougher. If you do not want to even risk the chance of multiples (although identicals could still occur) or increase the risk of delivering prematurely, and the success rates after transferring one, two or three are similar then I imagine that more and more people will opt for a single embryo transfer. Even better if that means that these couples have the option to do another single transfer down the road (utilizing a less expensive frozen embryo transfer) that may not have been possible if multiple embryos were transferred initially.
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