Does it have to be a birthing poem?
There is one by Khalil Gibran:
Your children are not your children.
They are the sons and daughters of life's longing for itself.
They come through you but not from you,
And though they are with you yet they belong not to you.
You may give them your love but not your thoughts,
For they have their own thoughts.
You may house their bodies but not their souls,
For their souls dwell in the house of tomorrow, which you cannot visit, not even in your dreams.
You may strive to be like them, but seek not to make them like you. For life goes not backward nor tarries with yesterday.
***
I like it because it is so much about the child being its own person and part of the universe and life itself... but maybe some people would be put off at a blessingway. Depends on your friend! You know her best.
Oh, and when I feel out of control with my daughter, that also helps, because I am reminded that there is this Life Force stronger than me taking care of her. I feel accountable to It but also taken care of by It... very nice during the birth.
AND- tee-hee, I forgot how much I loved this poem- it's also nice to know that life has this beautiful longing for itself, that it is meant to go on. That is nice for confidence.