With IVF, you and your doctor determine how many embryos will be transferred into your uterus. If you choose to have a single embryo transferred, then it would be impossible for you to have twins or triplets. However, there is no guarantee your embryo will successfully implant into the uterine lining the first time around. This is why many women, especially those who are unable to afford two or more cycles, often opt to have more than one embryo transferred.
Yes to some extent, for usually two embryos are placed in the uterus during embryo transfer . For women above 37 years, it might be decided to transfer 3 embryos. This is to improve the chances of pregnancy. Recently there is an upcoming trend of single embryo transfer which would definitely reduce the chances of multiple pregnancies.
The short answer to this question is no. The process of IVF, in and of itself, does not necessarily lead to a substantially higher risk of multiple pregnancy. In practice, the answer is slightly more nuanced. Statistically, women who undergo IVF have multiple pregnancies (twins, triplets, or higher-order multiples) at a higher rate than women who conceived naturally.