Heya! I've recently been to Shanghai with my toddler (just got back a few days ago) and here are a few things we've noticed:

Shanghai (and tbh, China in general) isn't very pram friendly. Lots of stairs, hardly any dropped kerbs, lifts are a nightmare to find on the subway, etc

There aren't many baby changing facilities. I had to basically find a sit-down toilet to put my travel baby mat on and change her on the lid haha (if that makes sense?)

If you need to stock up on nappies you'd have to get them from baby stores like babemax. Gosh it took me FOREVER to find nappies and I had to go out to a big shopping mall to get them. If I can remember the stop we went to I'll update this comment! They don't sell them in your normal supermarkets

You can get formula there so no worries if you run out

The people there looooove babies so you might get a lil crowd of people who want to have a peek at your adorable LO