There are many statements made by extreme NFP proponents which reduce credibility of the teaching. This is unfortunate because the actual teaching does not contain these flaws. All liners are not equal and some know this. The Pill is not designed to reduce liners, it to some extend does that however that is a minor affect of little significance and thus the issue. A proper response is **theoretically the reduced liner associated with oral contraception would statistically reduce the implantation rate of both break through eggs, and eggs produced through improper dosage and failures to properly administer the pill, these lost implantations would be considered chemical abortions. It should be clear the actual rate is unknown, and mostly due to pill administration issues, however statistically some of these abortions are occurring. **
I also would recommend the teaching be a top down format as: Sex is only within marriage. Marriage is primarily functioned to procreate. Contraception undermines the state of marriage by obstructing the primary objective to allow other objectives to be substituted and thus the marriage becomes redefined.
hope that helps