]That'd be a really poor reason.
Using that logic every time a woman has her period that'd be an abortion. After all that egg could have gotten fertilized.
Not really. I'm assuming this is their thought process:
1. Human Life begins at conception.
2. Conception happens when an egg is fertilized by sperm.
3. Birth control prevents that fertilized egg from being implanted.
4. Ergo, birth control ends a human life.
I'm not saying I agree with that logic, that it's good logic, or that it even holds true for everyone on the pro-life side. It just bugs when that side is portrayed as uniformly illogical, misogynistic, and/or inconsistent. I've known some pro-lifers in my time who honestly and wholeheartedly believed those first two points and were against abortion but not any form of birth control. When life begins is a somewhat subjective point.
On the day abortion is made illegal across the United States, the hard right will immediately retool themselves. They will redirect the energies and resources spent fighting abortion into fighting birth control and contraception with just as much ferocity as they had previously fought abortion.
Some of them will, and the Republican Party most likely would because it would woo the far right God-warriors that spur their race to the bottom, but not all conservatives or religious folks or even pro-lifers hit that anti-sex/anti-woman model.