What happens to the unused embryos in in - vitro fertilization? is that right? what is the difference between that and abortion?

Unused embryo in the in-vitro-fertilization can be kept frozen until a certain period of time until couple can decide if they will use it again to try for another baby. Many couple are having a difficult time of thinking of what to do in their unused embryo. Some might donate it to infertile couples rather than thawing it without donating. Letting the unused embryo go is not abortion because it does not have a life yet, but in abortion the baby is alive in the womb and the mother tries to remove the baby intentionally.