Some methods of family planning only prevent conception, and others prevent conception and have the potential to cause an abortion when a woman does conceive. Barrier methods (like condoms and diaphragms), fertility awareness methods (like Natural Family Planning), surgical methods (like vasectomies) and, of course, abstinence all carry no risk of abortion. If a baby is conceived while using one of these methods, no hormonal threat stands to deter the embryo from successful implantation in the mother’s womb.
But hormonal contraceptives, like the Pill, NuvaRing, patch, IUD, etc., are different. Because they alter a woman's body chemistry and physiology, hormonal contraceptives pose a risk to the survival of newly-conceived embryos by making the uterine environment hostile to implantation. This fact is readily acknowledged by medical groups and contraception manufacturers.