Bishops as the one quoted here think wrongly that birth control meds are used to only prevent pregnancy when it's inconvenient. These medications are used off label for the treatment of gynecological illnesses and to prevent pregnancy when a woman is on a medication that would destroy a fetus if she were pregnant. These situations do not enter their minds because they are not educated regarding women's health issues. I was once offered a medication for a skin condition that required a woman not be pregnant for three years after she STOPPED taking this drug.
In addition a woman cannot abort that which she has not conceived. Birth control does reduce abortion.