Probability to have twins with IVF is higher than usual. On avarage, the chances of twins in a traditional pregnancy is around 6% whereas the chances of twins with IVF reaches up to 25%. 

There are two types of twins - fraternal and identical twins.

Fraternal Twins

Fraternal twins are otherwise known as "non-identical" or "dizygotic" twins. This happens when two eggs are fertilised by two different sperms. In this case, twins have seperate placenta, amnion and chorion. Fraternal twins don't usually look like each other. They might or might not be the same sex.

Identical Twins

Identical twins are known as "monozygotic" twins. They are formed by splitting of one embryo. There are different types of monozygotic twins:

- DCDA: twins have their own placenta, inner membrane(amnion) and outer membrane(chorion)

- MCDA: twins have their own amnion, but share same placenta and chorion.

- MCMA: twins have same placenta, amnion as well as chorion. 

Identical twins are usually same sex and share same physical feauters but their personality might differ from each other.