I would tread very carefully! My best friend just had a baby and I sometimes found it really hard to bite my lip and she was very open to information, suggestions and discussion about birth - she asked me to be at the birth so we talked lots about what she wanted. I have to admit there were times when I was dying the say 'JUST STAY AT HOME!!! YOU'LL BE SAFER!!' but I knew that wouldn't go down well and she was very comfortable with the hospital she had booked into. In the end, it was her birth and her choices! I did make suggestions here and there, for example after one of her ante-natal classes she said 'we talked about the 3rd stage tonight, did you know they give you an injection once the baby is born to help deliver the placenta and prevent PPH?'...I responded with 'yep, they're referring to a managed stage and that definitely can have some advantages - there's also the option of a physiological 3rd stage, where you would birth the placenta without the injection - sometimes breastfeeding can aid in the delivery of the placenta...if you want some more info I can email you some links through that I find really helpful?'. She was really grateful for the information, and ended up decided she wanted to have a physiological 3rd stage. But, like I said...you have to pick your battles!