It is important to distinguish between monozygotic twins, which arise from the division of a single zygote and therefore have the same genetic endowment, and multizygotic twins, which arise from different eggs and sperm.
In the case of monozygotic twins, there are different types depending on when the embryo fragmentation occurred. Thus, we can distinguish between:
- Bi-chorionic-biamniotic twins.
- Monochorionic-biamniotic twins
- Monochorionic-monoamniotic twins
- Conjoined twins