Five embryos optimal for IVF

For women over 40 undergoing in vitro fertilization (IVF), transferring five embryos leads to the best outcome. The Society for Assisted Reproductive Technology (SART) currently recommends that no more than five embryos be transferred for IVF, in women over 40. However, this isn't based on very good data. To test the validity of the SART guidelines, researchers from the Brigham and Women's Hospital Center For Reproductive Medicine, Boston, evaluated and compared clinical outcomes when one to 11 embryos were transferred in women in this age group. Out of 863 embryo transfers, 142 patients received exactly five embryos, 392 received fewer, and 329 received more than five embryos.When fewer than five embryos were transferred, the overall pregnancy rate was 19 percent, and the live birth rate was 4percent. With five embryos, the pregnancy rate was 40 percent and the live birth rate was 23 percent. With more than five, the overall rate was 47 percent, and the live birth rate was 22 percent - but the risks of multiple gestations rose. With more than five embryos, the number of multiple pregnancies is increased, but the likelihood of a delivery is not increased. Triplets have a higher risk of all kinds of bad outcomes, and twins also have higher risks of prematurity. Women are also more likely to have diabetes and pregnancy complications with twins, especially if they're over 40. So there is good reason to stick with the SART recommendation, which is what is currently done in most clinics.