eSET irrespective of the availability of a good-quality embryo in the first cycle only is not effective in reducing overall twin pregnancy rates.

INTRODUCTION In several clinics, elective single-embryo transfer (eSET) is applied in a selected group of patients based on age and the availability of a good-quality embryo. Whether or not eSET can be applied irrespective of the presence of a good-quality embryo in the first cycle, to further reduce the twin pregnancy rate, remains to be elucidated. METHODS In patients <38 years two transfer strategies were compared, which differed in the first cycle only: group A (n = 141) received eSET irrespective of the availability of a good-quality embryo, and group B (n = 174) received eSET when a good-quality embryo was available while otherwise they received double embryo transfer (DET; referred to as eSET/DET transfer policy). In any subsequent cycle, in both groups the eSET/DET transfer policy was applied. RESULTS After completion of their IVF treatment (including a maximum of three fresh cycles and the transfer of frozen-thawed embryos), comparable cumulative live birth rates (62.4% in group A and 62.6% in group B) and twin pregnancy rates (10.1 versus 13.4%) were found. However, patients in group A required significantly more fresh (2.0 versus 1.8) and frozen (0.8 versus 0.5) cycles. CONCLUSIONS The transfer of one embryo in the first cycle, irrespective of the availability of a good-quality embryo, in all patients <38 years, is not an effective transfer policy for reducing the overall twin pregnancy rate.