There really isn’t much one can say other than “that’s so sad, I wish you could have shared “good” news with me. This must be very difficult for you. How can I offer my support at this difficult time?” You can also add “I have big shoulders if you need a shoulder to cry on, I give great hugs if you need one, and I am a good listener if you need to talk. I am here for you in any capacity that you need me.”
This will give your friend a good feeling that you care and that she is not alone because when you go through such a loss you feel isolated.