(designer note)
I suggest working perhaps twice the recommended number of rows of ribbing at the top of the sock. After test-driving this pattern on an actual baby I came to the conclusion that it needed a little more height and stretchiness to hang on to a wiggly baby’s leg. if you are concerned about the sock staying on, you could even work the whole cuff in ribbing and make it twice as tall as you want it so that it can be folded down over itself. That seems to help the socks stay on, too.
Fits newborns through three-month-olds.