[Single embryo transfer: is Scandinavian model valuable in France?].

The aim of infertility treatment is clearly to obtain one healthy baby. If the transfer of a top quality single embryo could provide a baby to all the patients, there would be no more discussion. The problem is that, nowadays, French pregnancy rates after fresh embryo or frozen embryo transfer are not the same as in Nordic countries. All studies show that in unselected patients, single embryo transfer decreases twin pregnancy rate but decreases pregnancy rate too. Pregnancy rate is dependent on embryo quality, women's age, rank of IVF attempt (clear data) but also on body mass index, ovarian reserve, smoking habits. All these data cannot be taken into account in a law. That is the reason why a flexible policy of transfer adapted to each couple is preferable. Each couple and each IVF team are unique and must keep the freedom to choose how many embryos must be transferred to obtain healthy babies, and to avoid twin pregnancies but without demonizing them.