"Rh 음성" refers to the Rh factor, a protein that can be present on the surface of red blood cells. Individuals who have this protein are classified as Rh positive (Rh+), while those who do not are Rh negative (Rh-). The Rh factor is important in blood transfusions and pregnancy, as incompatibility can lead to serious health issues. The Rh factor is inherited and is determined by specific genes. It is one of the key components of the ABO blood group system, which includes types like A, B, AB, and O. Understanding one's Rh status is crucial for safe medical procedures and maternal health.