Ds comes to all of my appts with me as it's hard to find a babysitter in the middle of the day. When I went to my U/s I asked if it was OK to bring him and they said not to unless someone else came to watch him. That was fine when DH could make it but for one of my scans DH was out of town and the one person I thought could maybe babysit was sick. So I brought him anyways and sat him in a chair with some snacks and he was really well behaved. He enjoyed seeing the baby too and probably helped him understand a little more too.