Why is an IVF pregnancy more likely to result in twins
During IVF usually more than one embryo is implanted into the uterus. Because there is a high chance that the implanted embryo will not result into a pregnancy doctors often implant more than one embryo to increase the changes of the woman getting pregnant.
Depending on your specific medical issues, your health, the quality of your embryos, you input and your doctors input anywhere from 1-5 embryos may be implanted. Your doctor will discuss the risk and benefits with you with each number that might be implanted. It is more common for doctor these days to err on the side of caution and implant as few embryos as possible.