Attitudes towards single embryo transfer, twin and higher order pregnancies in patients undergoing infertility treatment: a review.

The problems associated with twin and higher order pregnancies have assumed major importance, with international debate about multiple pregnancy; the single biggest risk with in vitro fertilisation (IVF). We have critically reviewed published papers on female patients' and their partners' views of single embryo transfer (SET) and twin or higher level pregnancies to identify the requirements needed to improve the acceptability of SET. Twenty relevant papers were identified and included in the review. Although the majority of IVF patients and their partners, in the more recent studies, exhibited a desire for twins rather than singletons, closer examination of the evidence revealed that elective SET (eSET) could become increasingly acceptable. As success rates of IVF have improved and the risks and consequences of multiple pregnancies are well-documented, patients have accepted the transfer of two rather than three embryos as standard practice. However, more would accept eSET if success rates approached those of double embryo transfer (DET). This emphasises the importance of improving success rates of eSET so that more patients can achieve a singleton birth with one IVF cycle. If patients were offered only SET, it is likely that this would be acceptable as the normal expectation of pregnancy is one baby. Measures to improve the acceptability of SET include: using eSET, especially with younger patients; including partners when providing risk information; improving eSET success rates; improving outcomes with cryopreserved embryos; changing reimbursement/free cycles to favour eSET; using legal enforcement.