[Elective single embryo transfer: a justified policy for selected patients].

Objective: Prevention of twin pregnancies using elective Single Embryo Transfer (e-SET) is now considered by many Assisted Reproductive Techniques teams as a necessity. The aim of this study was to assess the efficacy of e-SET in a prospective manner in a selective population of patients using Take Home Baby Rate per couple as principal parameter.
Patients and Methods: This prospective study was conducted from January 2003 to December 2004. Elective Single Embryo was proposed to women above 37 years in their first IVF or ICSI attempt. It was then performed only in cases when at least one embryo with high implantation potential (score-4 embryo in our embryo scoring) was obtained for transfer and one more (score-3 or score-4 embryo) was available for freezing.
Results: e-SET was proposed and accepted in 225 couples (25% of eligible couples and 7.8% of total population) and was possible in 96 of these). Two embryos were transferred in all other eligible patients (Double Embryo Transfer group=DET). Cumulative delivery rate after fresh embryo transfers and, if necessary, after frozen-thawed embryo transfers were 39.5% per couple e-SET group and 41.7% in DET group (NS). On the other hand, the percentage of twin pregnancies was significantly different between the two groups (2.6% vs 26.6% respectively; P<0.01).
Discussion and Conclusion: In women younger than 37 years in their first IVF/ICSI attempt, the elective transfer of only one embryo with high implantation potential strongly allowed to avoid twin pregnancies without any significant delivery rate decrease. This transfer policy is particularly efficient in laboratories displaying good results in their embryo freezing program.