Jacquemier's sign, also known as Chadwick's sign, is an early sign of pregnancy characterized by bluish discoloration of the cervix and vagina. This sign is named after French obstetrician Adolphe Jacquemier who first described it in the 19th century. Although Jacquemier's sign is a commonly used term, there are other synonyms used to describe this condition. These include the blue sign, Heger's sign, and Goodell's sign. These terms are used interchangeably with Jacquemier's sign and refer to the same condition. However, regardless of the terminology used, the presence of any of these signs is an important indicator of a possible pregnancy.