Analysis of the benefits and risks of multiple embryo transfer.

Depending on embryo quality and recipient factors, increasing the number of embryos transferred after in vitro fertilization may produce more pregnant patients or more multiple pregnancies. An analysis is outlined demonstrating how observations on the placement of two embryos in the uterus may be used to estimate the risks and benefits associated with the transfer of multiple embryos. Currently, the highest pregnancy rates are obtained with multiple embryo transfers, and these results are compared with the mathematical model.