Like everyone else, I think it is very common. I certainly had the same reaction, and in fact never held or even touched a baby, and I was around many, in the year and half that I said goodbye to our daughter and said hello to our son. And you know what? I don't think any of my friends ever noticed. It wasn't a big deal to them, but it was a huge deal to me, and I chose to put my feelings first.
It's ok to put your needs first. In the grand scheme of things, if you do something that will cause you great grief right now, you'll remember if for a very long time. Your friend, I don't think will remember or even notice if you take a little longer to visit. Send a card, email, text, whatever will keep you feeling peaceful. It's very kind of you to consider her feelings, and I know that's what makes you a wonderful friend, at the same time it's also ok to be considerate of your needs and your journey.
2008-Our Baby Girl, PTL born too early at 30w6d, Fought so hard... Forever Loved & Missed
2010- Lil' Bro, Pre-E at 29 weeks... Induced at 36w6d, Born 37w
2012- Lil' Sis, Super-imposed pre-e at 25 weeks, PTL & GD at 35 weeks, Evicted 36w