Just looking around melonbooks using google translate and I found pregnant girl pillow covers. look on the green stripe, under commercial goods then pillow cover. there kinda cool. if I didn't have family around i would buy one just for fun. check the out.

https://www.melonbooks.co.jp

https://www.melonbooks.co.jp/detail/deta..._id=141884

https://www.melonbooks.co.jp/detail/deta...t_id=69689