What constitutes a positive sign of pregnancy?

A positive sign of pregnancy is signified by definitive evidence of the presence of a fetus, and the audible fetal heartbeat serves as a clear and conclusive indicator. This heartbeat can typically be detected through a Doppler ultrasound as early as 10 to 12 weeks of gestation, marking a significant milestone in confirming pregnancy.

Other signs may indicate physiological changes in the body or suggest pregnancy, but they do not provide affirmative proof of fetal existence. For instance, deepening pigmentation arises from hormonal changes and may occur due to various other factors and conditions unrelated to pregnancy. Chadwick's sign, which refers to the bluish discoloration of the cervix, is a sign that can suggest pregnancy but is not definitive. Breast tenderness is often experienced early on during pregnancy, primarily due to hormonal fluctuations, but again, does not confirm the presence of a fetus. Therefore, the detection of an audible fetal heartbeat remains the most reliable and positive sign of pregnancy.