What sign is commonly associated with pregnancy at 12 weeks?

Chadwick's sign is a physiological change that can be observed in the female body during early pregnancy, typically around 12 weeks gestation. It is characterized by a bluish discoloration of the cervix, vagina, and labia due to increased blood flow and vascularity in the pelvic area as a result of hormonal changes. This sign is one of the early indications of pregnancy and can be an important clinical finding during a physical examination of a pregnant patient.

Although other signs and changes occur during pregnancy, Chadwick's sign specifically provides evidence of increased blood supply which is a direct result of the hormonal shifts occurring in the body at this stage. This change is an early manifestation and typically becomes evident by the end of the first trimester, making it a reliable marker at approximately 12 weeks.