Sorry to hear about your mc

I'd just be honest with her and tell her you will find it hard to handle being around a newborn - if she's a true friend she'll understand. My cousin was due a couple of months after me but sadly she has m/c and I've told her that I'll totally understand if next time she's visiting she doesn't want to be around me and/or baby depending on when she visits as I'd totally get where she's coming from (I fuond it hard to make the decision to see a friend with a 6 month old a couple of months after my mc).
hugs
xx