How much does IVF increase a woman's odds of having twins or multiple babies at once?

It is true that women who undergo IVF are at a higher probability of having twins or multiples, but mainly, it depends on certain factors. If you are opting for IVF treatment and choose to transfer only one embryo, it means for sure that you cannot have twins or multiples. However, there is no guarantee that the single embryo will fertilize. In order to increase the chances of becoming pregnant, most women undergoing IVF opt for multiple embryos, which increases the odds.