I got these booties as a shower gift and didn't realize that they would fit my newborn so early. The 0-6 month size is perfect for her feet. She was born 9lbs 4 oz, and these fit her pretty much immediately. The design of the bootie is made to snap around the ankle, therefore keeping the bootie from falling off. We have not lost a bootie yet, and if I do, I will buy another pair because we love these so much!  I have them in brown, and they go with pretty much any outfit.  The fleece bootie is designed also to be easy on and off,  there are two snap settings for getting a tighter fit.  Right now I am in the tightest setting, and her toes have room to grow inside the bootie.  I am happier putting these on her than socks! Socks come off too easily, or are too hard to wrestle over her toes.  The booties are much nicer and easier to work with,  HIghly recommended! In fact, I am getting these for my girlfriends baby shower next month!