If I gave someone a load of stuff that I was no longer using, I think that I would assume that they would do what they wanted with it, unless I specifically said to them that I would like it back once they had finished.
I gave all my maternity clothes to a friend, and was very lucky that although she had lent them to friends after she had used them, she had most of them returned to her, so could give them back to me.
We are going to be giving some bits and pieces to my brother and his GF who are due a baby about 7 months after ours is born, but we will be saying to them that we want it all back again when they have finished as we *may* have another (and even if we don't, I would want to try selling it to recoup some cost!).
I think I probably would be a bit fed up in your situation, but probably more cross with myself for not making it clear that I wanted the things back (if that makes sense?).
Have you tried asking her if she has any bits left? That is what I did with the maternity clothes, I just asked her if she still had them, and if so could I have them back.