Chadwick's sign

Chadwick's sign is a bluish discoloration of the cervix, vagina, and labia resulting from increased blood flow. It can be observed as early as 6 to 8 weeks after conception, and its presence is an early sign of pregnancy.

These color changes were discovered in approximately 1836 by French doctor Étienne Joseph Jacquemin (1796-1872), and are named after James Read Chadwick, who drew attention to it in a paper read before the American Gynecological Society in 1886 and published in the following year, wherein he credited Jacquemin for their discovery.