Most preemie zipper sleepwear is cotton-based — regular or organic cotton — typically in interlock or jersey knits with a lightweight feel.
They commonly use a front full-length zipper plus protective features such as a safety tab, a soft zipper cover, or a covered zipper at the neck to protect the baby’s skin and prevent snagging.
Preemie zipper gowns are described for preemies and newborns weighing about 6 to 9 pounds. The 0–6 month size is noted to run larger.
Some zipper items are footed sleepers, while gown styles usually have an elasticized bottom or band to simplify dressing and diaper changes.
Garments are described as lightweight and some pieces specifically note breathable, soft cotton jersey construction.