The moment of conception does it begin before the fertilized egg implants and if so then.....?

When is the moment of conception and what if the fertilized egg does not implant was that a human baby? What is a woman uses the birth control pill, an IUD or depo shot as those methods deter the fertilized egg from implanting. So, according to those that believe life begins at conception do they believe women that use birth control are abortionists?