This is an interesting case. A surrogate pregnancy, and the parents find out that the fetus is most likely going to be born with Down's syndrome. They wanted the surrogate to have an abortion, the surrogate didn't want to.
I'm not sure she was obligated to have an abortion, but the parents were not legally (by contract) required to raise the child if they didn't want it. So the surrogate would have to care for the child, or she would have to give it up for adoption.
There's something to be said about personal autonomy, and the limits of it. I hate to put limits on personal autonomy, and this case doesn't seem to push me into limiting it. The surrogate gets to decide whether or not she should have an abortion, because it is her body, but its not her baby. To an extent she's limited part of her autonomy in accepting someone else's baby in her body. She can't just have an abortion without their permission, but they can't compel her to have an abortion.
In the end, she had an abortion. Probably, for the best.