Can you give a bone marrow while pregnant?

I'm 21 and 6 weeks pregnant and my mom just got a horrible phone call from my aunt. She was called and said her 7 year old daughter (my cousin) is getting sicker each day and needs a bone marrow transplant. She was wondering since me and my cousin have same blood type that if I would see if I matched her bone marrow? Would I be able to do this pregnant because it will break my heart if I can't.