Should elective single-embryo transfer be done in first-time IVF patients under age 37?(POINT/COUNTERPOINT)

It can prevent multiples and prematurity.

Medical professionals have a responsibility to work toward prevention of prematurity. The data clearly show that woman who become pregnant with multiples are at increased risk of premature delivery. Thus, elective single-embryo transfer (eSET) is indicated in women under age 37 years because thay have the highest risk of becoming pregnant with multiples when more than one embryo is transferred during in vitro fertilization.

For example, a number of studies have indicated that women in this age group are more prone to twin pregnancies, while those over age 37 are not-and are in fact less likely to become pregnant or to miscarry when they do become pregnant. Elective single-embryo transfer is not for these older women, but it is the right thing for younger women who have a higher likelihood of becoming pregnant and of carrying the pregnancy to term, particularly given the improved embryo selection processes that are now possible.

Furthermore, data consistently support the use of eSET. In Belgium, the practice of using just one embryo in every first IVF cycle in those under age 36 years has resulted in a marked reduction in twin pregnancies, and in the elimination of triplet pregnancies among those in this age group. This has occurred without a reduction in the overall pregnancy rate.

Similar results have been seen elsewhere. In Sweden, where 70% of transfers are single-embryo transfers the twin rate is down to 5% and pregnancy rates are slightly up. And in at least one center in the United Kingdom, the cumulative pregnancy rate rose with the introduction of eSET, and the multiple pregnancy rate dropped substantially.

Similarly, data from Australia show a tremendous drop in the incidence of multiple pregnancies with the introduction of eSET. In the United States, multiple studies--including a number of abstracts and posters presented this year at the annual ASRM meeting--showed that pregnancy rates remain stable, while twinning rates drop dramatically following eSET at the blastocyst stage.

The rate of prematurity is 6%-7% in singleton pregnancies versus 40%-50% in multiples, and prematurity is associated with a vast array of clinical syndromes and with low birth weight.