Hey!
I also have one of the wee SWCAH kids- my daughter is 20 months and about 21.5lb, which is <5% on the weight growth chart. However, she is in the 40% for height. It’s weird, her labs 2 months ago indicated that she was oversupressed- which I thought meant more weight and less height.
Our pediatrician recommended the whole milk (which we were doing anyways) and also suggested we put butter in everything that we could (on her bread, melted over veggies, etc.) I’ve also stopped watering down whatever juice she gets. I also have to keep reminding myself that because she is smaller than normal, she’s inherently going to eat less than what the toddler food guides recommend. I always hate it, tho, when she decides to take a day off eating- I get freaked out that she’s getting sick and am constantly checking her to make she not starting a fever!
Good luck--
Martha