So glad I found these! My 1 month old whos 10 lbs and 22 inches fits in a size 3 months with plenty of room to grow. These bodysuits are soft and perfect for wearing under 2 piece outfit so babys tummy isn't showing every time you pick her up. The sleeveless design is perfect for under dresses and doesnt add too much heat under a Summer outfit. Ill be buying more once she outgrows these.