You may rest easier for you have been misinformed. Both the Pill and the NuvaRing do NOT allow fertilization to even occur. Their primary method is to supress ovulation. If an egg does get released, and it is fertilized implantation generally does result and the woman does get pregnant. The hormones do NOT cause abortions once the egg is implanted.
Read this for more accurate info from acutal doctors:
http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retri eve&db=pubmed&dopt=AbstractPlus&list_uids=105616 57
Th IUD ALso works primarily by preventing fertilization, either by hormones to prevent ovulation or by killing the sperm (copper).
Only in rare cases is an egg actually fertilised and then the IUD prevents implantation.
And remember, NFP can still allow for fertilisation and sometimes that embryo does not get implanted, so by the strict standards of anti-abortionists, they would call that an abortion.
Anti-abortion websites routinely lie to people as a cynical method to increase their membership. I believe doctors that know what they are talking about rather than anti-abortion laymen that knowingly lie to increase their numbers.