Which physical examination finding is typically present at 12 weeks of a singleton pregnancy?

At 12 weeks of a singleton pregnancy, Chadwick's sign is typically present. This sign is characterized by the bluish discoloration of the cervix, vagina, and labia due to increased blood flow and vascularization associated with early pregnancy. It usually appears around the 6th to 8th week of gestation and becomes more prominent as the pregnancy progresses. This physical examination finding is one of the earliest signs that can indicate pregnancy, reflecting the physiological changes occurring in the body in response to rising hormone levels, particularly estrogen and progesterone.

Other physical signs, such as uterine size or blood pressure changes, develop at different stages of pregnancy and may not be present at 12 weeks. The uterus typically rises above the pubic symphysis, but it does not reach the umbilicus until around 20 weeks of gestation. Blood pressure in a typical pregnancy may actually decrease slightly due to hormonal changes and increases in plasma volume, but this varies among individuals. Hyperreflexia is not a standard finding associated with early pregnancy and is more related to neurological conditions or complications rather than normal physiological changes.