Cotton For Newborns : 

For newborns, their skin is delicate, and requires the safest, and softest material such as 100% Cotton. Unlike polyester and other synthetic clothes that can cause irritation to newborns, 100% cotton keeps babies cool and comfortable. It's breathable, the fibers are strong, and aids in regulating body temperature. 

Almost ALL products are made by AndyWawa and tenderly crafted with 100% cotton.

with the few exceptions that aren't being a few accessories, and some pieces that are still a majority cotton.