Editing Embryo transfer (section)

=== e-SET<!--'Elective-single embryo transfer', 'Elective-Single Embryo Transfer', 'E-SET' redirect here--> ===
{{Redirect|e-SET|the mathematical concept|E-set}}
The technique of selecting only one embryo to transfer to the woman is called '''elective-single embryo transfer'''<!--boldface per WP:R#PLA--> ('''e-SET'''<!--boldface per WP:R#PLA-->) or, when embryos are at the blastocyst stage, it can also be called ''elective single blastocyst transfer (eSBT)''.<ref name=mullin>{{cite journal | vauthors = Mullin CM, Fino ME, Talebian S, Krey LC, Licciardi F, Grifo JA | title = Comparison of pregnancy outcomes in elective single blastocyst transfer versus double blastocyst transfer stratified by age | journal = Fertility and Sterility | volume = 93 | issue = 6 | pages = 1837–43 | date = April 2010 | pmid = 19249756 | doi = 10.1016/j.fertnstert.2008.12.137 | doi-access = free }}</ref> It significantly lowers the risk of multiple pregnancies, compared with e.g. Double Embryo Transfer (DET) or ''double blastocyst transfer'' (2BT), with a twinning rate of approximately 3.5% in sET compared with approximately 38% in DET,<ref name=Fauque>{{cite journal | vauthors = Fauque P, Jouannet P, Davy C, Guibert J, Viallon V, Epelboin S, Kunstmann JM, Patrat C | title = Cumulative results including obstetrical and neonatal outcome of fresh and frozen-thawed cycles in elective single versus double fresh embryo transfers | journal = Fertility and Sterility | volume = 94 | issue = 3 | pages = 927–35 | date = August 2010 | pmid = 19446806 | doi = 10.1016/j.fertnstert.2009.03.105 }}</ref> or 2% in eSBT compared with approximately 25% in 2BT.<ref name=mullin /> At the same time, [[pregnancy rate]]s is not significantly less with eSBT than with 2BT.<ref name=mullin /> That is, the cumulative live birth rate associated with single fresh embryo transfer followed by a single frozen and thawed embryo transfer is comparable with that after one cycle of double fresh embryo transfer.<ref name="auto" /> Furthermore, SET has better outcomes in terms of mean gestational age at delivery, mode of delivery, birthweight, and risk of [[neonatal intensive care unit]] necessity than DET.<ref name=Fauque /> e-SET of embryos at the cleavage stage reduces the likelihood of live birth by 38% and multiple birth by 94%.<ref name=gelbaya>{{cite journal | vauthors = Gelbaya TA, Tsoumpou I, Nardo LG | title = The likelihood of live birth and multiple birth after single versus double embryo transfer at the cleavage stage: a systematic review and meta-analysis | journal = Fertility and Sterility | volume = 94 | issue = 3 | pages = 936–45 | date = August 2010 | pmid = 19446809 | doi = 10.1016/j.fertnstert.2009.04.003 }}</ref> Evidence from randomized, controlled trials suggests that increasing the number of e-SET attempts (fresh and/or frozen) results in a cumulative live birth rate similar to that of DET.<ref name=gelbaya />

The usage of single embryo transfer is highest in Sweden (69.4%), but as low as 2.8% in the USA. Access to public funding for ART, availability of good [[cryopreservation]] facilities, effective education about the risks of multiple pregnancy, and legislation appear to be the most important factors for regional usage of single embryo transfer.<ref name=Maheshwari2011>{{cite journal | vauthors = Maheshwari A, Griffiths S, Bhattacharya S | title = Global variations in the uptake of single embryo transfer | journal = Human Reproduction Update | volume = 17 | issue = 1 | pages = 107–20 | year = 2010 | pmid = 20634207 | doi = 10.1093/humupd/dmq028 | doi-access = free }}</ref> Also, personal choice plays a significant role as many subfertile couples have a strong preference for twins.<ref name=Maheshwari2011 />