Seamless Material: 85%Bamboo 7%Nylon 8%Spandex (Maternity Underwear); 92%Nylon 8%Spandex (Maternity Shapewear). Stretchy material is slightly elastic and stretches easily. Machine Wash 【SIZE】: panties M( hip:35”-41” ), panties L( hip:42”-44” ), panties XL( hip:45”-47” ). Women's maternity pre pregnancy over bump underwear should be machine wash cold, gentle cycle. Tumble dry low.