>If the IUD stops implantation then abortion has occured.
The vast majority of fertilized eggs never attach to the uterus wall. It’s not abortion.
As I remember it, the "research" indicating that the "vast majority" of fertilized eggs fail to nidate was done in conjunction with an examination of uteri which had been removed via hysterectomy, many of which were already abnormal,(that's why they were removed). But EVEN IF most early embryos perish, deliberately killing prenatal human beings is still morally evaluated as abortion.