Angel- Its awesome your MIL is a midwife! I wish I could get mine to see its not "risky" to give birth without an epidural. Shes surprised I haven't lost a baby since I refuse to get another epidural (felt forced with my first and it messed up my back)..
Not doing a midwife but gift ideas:
If you don't know her super well a gift card to a restaurant, a nice card and picture of the baby..
if she likes to bake: a "bakers" basket: apron, measuring cups, cookbook and a "brownies in a jar" mix
gardener: make a garden bag and apron then get some gardening tools
a drawer: a "art kit" with pencils and pads of paper etc in it
Honestly just about any hobby could turn into a nice gift idea and if I was doing a midwife Id probably do something that didn't have to deal with her job since she spends so much time at it.. Oh and I do mostly handmade gifts, which I guess isn't helpful for those who can't sew.. Any gift though Id put in a picture of the baby because I know most care providers love having pictures of the babies