Rh refers to the Rh blood typing system, which is one of the commonly used clinical methods of classifying blood types, along with the ABO blood typing system.
There are two types of Rh blood groups, positive and negative, which are categorized mainly by the presence or absence of D antigen on the surface of the red blood cell membrane. Rh is positive when D antigen is present on the surface of the red blood cell membrane and is expressed as Rh(D)+; Rh is negative when no D antigen is present on the surface of the red blood cell membrane and is expressed as Rh(D)-.
The vast majority of people have Rh-positive blood, and only a very small percentage have Rh-negative blood, also known as “panda blood”.
In terms of blood function, there is no significant difference between Rh-positive and Rh-negative blood, but for women, Rh-negative women have a relatively high likelihood of hemolysis of the newborn during pregnancy, and need to do a good job of maternity testing and prevention.