People who are pro-life (or more accurately, anti-choice) are often the same people who fight against programs that would reduce unwanted pregnancies: access to contraception; and good sex ed.
As they see it, providing access to contraception gives permission for sex outside of marriage, which is another thing that they vehemently oppose.
They're ideologically stuck.
If people are serious about reducing abortions, the best thing that they can do is advocate for access to contraception and support comprehensive sex ed.
Source: link.