An elective Single Embro Transfer or eSET, as part of an In-Vitro Fertilization (IVF) with or without Intra-Cytoplasmic Sperm Injection (ICSI), is recommended in cases where a multiple pregnancy is a risky choice for the health of the expectant mother and developing embryos.
In eSET, ‘elective’ means that we select only one embryo – the best one –for transfer in the womb. After IVF with or without ICSI, a couple may end up with more than one good quality embryos that can be transferred. Common practice has included transferring at least two, as the higher number of embryos offers a better chance for a successful implantation.
However, with improvement of culture methods and media, the transfer of one embryo as compared to more than one embryo, has shown almost equally high success rates*. So, depending on your individual circumstances, we will account for the risks of a multiple pregnancy, without just maximizing your implantation chances.
An eSET is beneficial for women with a good prognosis for pregnancy with IVF and who are younger than 30 years of age.
Additionally, for women that undergo IVF with or without ICSI for the first time, or already had a successful first outcome.
Also, for women that have a good number of embryos, which can be considered for the selective, or elective, part of the procedure.
An eSET is also highly recommended to women that are predisposed in developing pregnancy complications / conditions (for instance pre-eclampsia, gestational diabetes) and / or have a history of premature delivery. A multiple pregnancy can significantly increase the chance of such complications / conditions, even if there is no such pre-disposition. Premature babies may be at a risk of developing some short term or long term conditions (for instance cerebral palsy, gastrointestinal and lung problems).
An eSET can be performed either at 2-3-day stage embryo or at the stage of blastocyst. But usually, the blastocyst stage is preferred, as the more developed the embryos are, the better the embryo selection process is.
The best embryo selection is done by our embryologists, who study the morphological features of the early embryos ideally through the use of the EmbryoScope® time-lapse imaging system, rather than conventional microscopy. With the EmbryoScope® system, our embryologists have access to each programmed cell division that takes place in the initial stages of development, and based on that information, they assess all embryos in detail and precisely select the best one.
The rest of the procedure is not different from any other embryo transfer. A mock embryo transfer for improving the efficiency of your single embryo transfer, as well as the use of Implantation Support Medium Transfer (ISMT) for increasing the chances of implantation can also be employed prior eSET.
eSET is associated with high rates of live births. In studies*, where elective single embryo was compared with more than one embryo transfers, eSET was shown to be almost as efficient as the latter. The slightly lower success of eSET can be explained by the fact that this method is often offered to women that are not always the best candidates for it (for instance, because they are older or had a previous failed IVF).
If you are considering an eSET as part of your IVF, our specialists can advise you on the best option for you particular circumstances.
If you have only one embryo after IVF, then selection cannot take place, as it cannot be elective. This sole embryo is the only choice and is transferred in the womb.
References
* Gardner DK, Surrey E, Minjarez D, Leitz A, Stevens J, Schoolcraft WB (2004). Single blastocyst transfer: a prospective randomized trial. FertilSteril. 81(3): 551-5. (PMID: 15037401)
Davis OK (2004).Elective single-embryo transfer–has its time arrived? N Engl J Med. 351(23):2440-2. (PMID:15575063)