Wikipedia
Hoko (doll)
A , is a kind of soft-bodied doll given to young women of age and especially to pregnant women in Japan to protect both mother and unborn child. Traditionally, hōko dolls were made of silk and human hair. They would be stuffed with cotton. The dolls could be made for both boys and girls, however boys' dolls would be given up and "consecrated" at a shrine when boys turned fifteen. Girls would give up their dolls at marriage. The dolls were given to children either at birth, or on special days shortly after birth.
Modern day hōko dolls have been created with technology to monitor babies.