It sounds like you did the right thing. I wouldn't have made it about the pregnancy as some others suggested as it was her right not to tell she was pregnant. I had a client who was pregnant when her child started with me and did not tell me, but told me when she was 3 months along at the same time she told everyone else. I didn't see anything wrong with it. A lot of moms keep their kids in daycare during mat leave anyway, so one can't assume it is short term, although this mom probably wouldn't have stayed! Good luck!