Storchenkinder Wool
On a newborn baby, the pull-on style cover comes up higher than the cord stump so just like clothing, it is fine over the cord on a brand new baby.

Size 2, 21 pounds, 20 months old
Almost 9 months old, 22 pounds, wearing size 2. Plenty of growing room. Stretchy and comfortable on the tummy.
Close up of the knit wool