Five embryo transfer for women over 40
It seems like studies on the optimal number of embryos to transfer are pointing in opposite directions. An earlier study showed that single embryo transfers were as good as multiple when the success rate of live births was considered. Now a study by Dr. Elizabeth Ginsburg from the Brigham and Women's Hospital Center For Reproductive Medicine, Boston shows that five embryos is the optimal number for women over 40.
The study involved 863 transfers in which 142 patients received five, 392 received fewer, and 329 received more than five embryos. It showed that when fewer than five embryos were transferred, the overall pregnancy rate was 19 percent, and the live birth rate was four percent. With five embryos, the pregnancy rate was 40 percent and the live birth rate was 23 percent. More than five embryos resulted in too high a risk of multiple births.
The earlier studies considered all ages so for younger women perhaps the single embryo transfer is viable.