My sister bought a bola necklace, also called a harmony necklace. It is a metal cage that houses a colored ball inside. The ball has a chime in it. The purpose is so that the babies hear the chime and it becomes a comforting sound to them. I will wear it for the duration of the pregnancy.
After birth, the necklace will be passed on to Missi and Court. The idea is that Missi will wear it (on a shorter chain) or it can be put on a stuffed animal etc. The babies will hear the same chime and be comforted and soothed as they were in utero.
These necklaces are common in surrogacy 🙂