I typically do nothing. Usually because I don't know it's their birthday until the day of and that says to me they don't want me to do anything.

This is my MBs first birthday celebrated as a mom. She had a rough pregnancy and these first 9mos have been one challenge after another. So I want to acknowledge what the past year has meant.
Anyway, the girls are making her a "52 deck". Their grandma sent me a USB with all their best photos of mom and babies and on the color side of the playing card will have a picture pasted and the back side will list one reason. The deck is called "52 reasons you're a great mom"
This will be my second 52 deck (different family) and if the reaction of the last MB is any indicator, these cards become a treasure. My MBs have been, and are, wonderful mommies.

Babysitting certificate and a nice card is what our nannies have generally given for special events like birthdays or holidays -- very appreciated!

I took the kids to my place over night for my mbs birthday and bought her a bottle of wine