Help I wanna support my friend, but...?

I have a very close friend who has been trying for ten years to have a child. She has been thru many, many miscarriages and a stillbirth at seven months. She is pregnant again. The doctors are doing everything they can, working with her around the clock to try and maintain the pregnancy. She will be due in April. Now, I have been on this roller coaster with her for ten years. When she hurts, I hurt. And knowing the chances that this baby has to survive, which are not good, I am afraid to get too attached. She can sense that i am wary of getting involved too deeply this time. Does anybody have a suggestion as to how I can keep my distance while still giving her as much support as possible.