Single Embryo Transfer Ups Chance of Term Birth
Single transfers more likely to result in singleton full-term birth despite lower pregnancy rate overall
WEDNESDAY, Dec. 22 (HealthDay News) -- Single embryo transfers result in fewer pregnancies than double embryo transfers, but the former approach substantially raises the chances of a term singleton birth, according to research published Dec. 21 in BMJ.
To compare live birth, multiple live birth, miscarriage, preterm birth, term singleton birth, and low birth weight outcomes, David J. McLernon, Ph.D., of the University of Aberdeen in the United Kingdom, and colleagues reviewed data from studies in which 1,367 women had been randomized to single or double embryo transfer.
The researchers found that single embryo transfer yielded a lower pregnancy rate than double embryo transfer in a fresh in vitro fertilization cycle. The overall live-birth rates for fresh single embryo transfers and double embryo transfers were 27 and 42 percent, respectively, and the multiple-birth rates were 2 and 29 percent, respectively; however, adding a frozen single embryo transfer after the single fresh embryo transfer raised the cumulative live-birth rate to 38 percent. Odds for a term singleton birth were nearly five times higher for single embryo transfer than for double embryo transfer.
"Elective single embryo transfer results in a higher chance of delivering a term singleton live birth compared with double embryo transfer. Although this strategy yields a lower pregnancy rate than a double embryo transfer in a fresh in vitro fertilization cycle, this difference is almost completely overcome by an additional frozen single embryo transfer cycle. The multiple pregnancy rate after elective single embryo transfer is comparable with that observed in spontaneous pregnancies," the authors write.
One author disclosed travel and accommodation sponsorship by Schering-Plough.