What does it mean to be rhesus negative?

Do you have friends who are rh negative but new to it all?
Here is a brief introduction to let them know what we are all about:

• Being rh negative means testing negative for the rhesus gene (D).
• The term rhesus derives from the rhesus monkey carrying the gene.
• The rhesus factor was discovered by Karl Landsteiner in 1937, 37 years after he has discovered the major ABO blood groups.
• Women who are rh negative, already carry antibodies and are pregnant with an rh positive fetus, need an Anti-D shot or the fetus will likeliest die.
• Rh negative blood can be given to rh positives, but not vice versa
  (actually it can be given once if no antibodies exist, after which antibodies will be built and the next time it would likely be fatal).
• Rh negative blood is rare on a global scale, but the frequencies vary. Some tribes carry zero percent while some ancient populations were likely 100 percent rh negative.
• The rh negative blood factor is inherited recessively. +/- would be rh positive heterozygote and +/+ rh positive homozygote.
  If you are +/+, your offspring will be rh positve.
  As long as you are rh negative, your offspring will always be rh positve heterozygote (+/-) or rh negative.

• The easiest way to avoid the rh disease is for an rh negative woman to marry an rh negative man.

For more information, go to the top right hand corner of this site and use the search box to get answers to questions that you have!