Dear J.,
First, CONGRATULATIONS on your precious baby girl!!! I have a girl as well.
Regarding your question, I believe that you should do whatever your heart tells you to do. I don't believe that you should follow a certain etiquette if it is on your heart to let someone know how much you appreciate them. So many professionals rarely receive a gesture of thanks no matter what their services or care to you or loved ones might be.
For me personally, my daughter was a fertility baby and when I finally did get pregnant, at 9 and 1/2 weeks I hemorrhaged, lost 4 units of blood, developed multiple thecolutian cysts in both of my ovaries. I great deal to the story, but God saw us through everything and I delivered her by C-section when most of the doctors never believed that I would make it another week. Through that experience and so many people who had come into my life throughout this process, I just wanted them to know how grateful and blessed I was to have such wonderful people all around me doing everything humanly possible to bring my sweet baby girl into the world.
So, I say that whatever you feel to do or if you don't think its necessary, it is your choice and you should just do what you think is best and fits your situation. I don't think you should go by any "rules of proper etiquette", follow your heart and create your own rules. Hope this helps you and again a great big Congrats to you !
T.