My son was straight into 000. I didn't bother buying any 0000's with him. My daughter was quite small though and she was in 0000's and 000's for quite a long time, as she had reflux and didn't gain weight as fast as she should've. I wouldn't buy too many suits too soon, anyway. When your bub is born you can buy clothes in the right size then. Different brands fit different too. For example, I found Target baby clothes are quite large for their size, Pumpkin Patch is too. While Bonds is pretty much the right size.