We can surmise from how the Church approaches those two issues that contraception is **not **more grave than abortion.
In a situation where a woman has been raped and conception has occurred the Church, while condemning the horrific evil of rape, asserts that the innocent human life cannot be terminated through abortion.
In a situation where a woman has been raped and conception has not occurred the Church does permit the use of non-abortive contraceptives.
If abortion and contraception were even considered equally grave then they would have to be morally treated the same in the situation above.
DISCLAIMER: Catholic Answers has turned over the archive to Catholic-Questions.org and no longer owns, manages, or moderates the forums. For additional apologetics resources please visit www.catholic.com.