A contradiction is this.
"The cat is on the mat."
"The cat is not on the mat."
Once you know which cat and which mat, one's got to be true and one's got to be false.
In the case of abortion,
1) All abortions where the life of the mother is not in jeopardy are morally wrong.
is contradicted by
2) Some abortions where the life of the mother is not in jeopardy are not morally wrong.
But all you need for 2 is at least one. If 2 is true, then some, indeed most abortions where the mother's life is not in jeopardy can be morally wrong. Just not all.
It's important to realize what a real contradiction is, and what it is not.
In ethics we sometimes accuse people of contradicting themselves when they really aren't. There is nothing about being pro-life, for example, that logically entails that you ought also to be against the death penalty. In one case you have fetuses who are not guilty of anything, in the other case, you have guilty capital criminals. On the other hand, there's nothing about pro-choice that guarantees that you should support the death penalty. In one case you have fetuses who are not given the legal rights of persons (whether they should be or not is a different issue) and on the other hand you have capital criminals who, whatever they have done, are considered to be persons by the law.