Actually, IVF is the only fertility treatment that allows you to control the risk for multiple pregnancy. In IVF, the chance for pregnancy and the risk for multiple pregnancy is determined, in part, by the number of embryos you decide to place into the uterus. Generally, a higher number of embryos results in a higher chance for pregnancy and a higher risk for multiples.
In order to reduce the chance for twins, a couple can choose to transfer a single embryo. The chance for having a twin pregnancy would be 0.3%.