I have a hospital appointment that I'm just beyond terrified of (due to PTSD etc), and I know that it will all go much more smoothly if I can avoid a panic attack in the waiting room and remain sufficiently anxiety-free throughout examinations to communicate clearly with the medical staff. In the past, I have used diazepam and it has usually helped enough to get through. But how safe or unsafe would it be as a one-off at 28 weeks pregnant?