This hasn't been misreported. I watched the exchange and this is what he said. The problem is that, as others mentioned, he got himself in a quagmire because he wants to appeal to the evangelical voters, who are anti-abortion, but he doesn't know enough about the nuances of the debate.
We'll see more of this anytime Trump is asked to actually offer policies. He's full of bluster about bombing ISIS, building a wall, etc, but he can't explain how he will do these things, where the money will come from, or any of the other practicalities.
It's been frustrating to see how rarely he is asked to explain how he will do these things, but as the campaign continues and he is pressed on these matters, he will make more of these missteps. Unfortunately, his followers are so enamoured with him that they seem to have very little impact on his popularity.