They will use the example of a wife, whose husband no longer sleeps with her, who gets pregnant while having an affair.
In order to protect her privacy (ie: so that her husband doesn’t catch her cheating on him, and divorce her leaving her penniless) she has to have an abortion.
Or, a girl is going with two boys at the same time, and doesn’t know which of them is the father of her child. (Let us further suppose that they are of different races, and if she guesses incorrectly, the boy will immediately be able to tell that the child is not actually his.) In order to avoid a lot of awkward questions, she decides to have an abortion, in order to prevent the two boyfriends from finding out about each other.
Of course the real solution to these dilemmas is not to get into the situation in the first place, and always to keep it as a general principle never actually to do anything that you wouldn’t want to be caught doing.