Rh factor

[ ahr-eych fak-ter ]

noun

, Physiology.

1. an inherited antigen found on the red blood cells of most people and certain other primates: those with this antigen are Rh positive while those lacking it are Rh negative, the determination of which is especially important when assessing blood-type compatibility for transfusions and pregnancy.

Rh factor

noun

1. an agglutinogen commonly found in human blood: it may cause a haemolytic reaction, esp during pregnancy or following transfusion of blood that does not contain this agglutinogen Full namerhesus factor See also Rh positive Rh negative

Rh factor

/ är′āch′ /

1. Any of several antigens present on the surface of red blood cells in most humans. People with Rh factors are classified as having a blood type that is Rh positive , while people who lack the antigen are said to be Rh negative and can produce powerful antibodies that destroy red blood cells if given a blood transfusion from an Rh–positive donor. A woman who is Rh negative and is pregnant with an Rh–positive fetus can produce antibodies that are life threatening to the fetus.
2. See Note at blood type

Rh factor

1. Any of several substances found on the surface of red blood cells in persons.

Notes

An Rh-negative woman who gives birth to an Rh-positive baby may develop antibodies to the Rh factor during her first pregnancy. These antibodies may cause a disorder in Rh-positive babies conceived afterward that could result in the death of the infant if the condition is not recognized and treated.

Word History and Origins

Origin of Rh factor¹

First recorded in 1940–45; so called because first found in the blood of rhesus monkeys

Word History and Origins

Origin of Rh factor¹

C20: named after the rhesus monkey, in which it was first discovered