Anything you take while pregnant can or may not harm an unborn baby. As long as her doctor knows what she's taking and he's monitoring it when she takes it she will be ok. The best thing obviously is to keep her doctor informed on any changes that don't seem normal. Eat right and take care of her body. Stay inside on high allergy days so an attack doesn't come on. I know it's not much , but I hope I've helped a little. Good luck with your new grand baby.