Bombay blood group

 The rare, Bombay blood group was first discovered in Mumbai ( Bombay) in 1952 by Dr Y M Bhende. Each red blood cell has antigen over its surface, which helps determine which group it belongs to. In addition to the common A, B, D antigens in the positive blood group people, H antigen is also seen in all blood groups. Thus, in the AB positive blood group,  antigens A, B, D and H are found. A positive will have A, D and H antigens; B positive will have B, D and H antigens. O positive lack A, B but have D antigen. In the Bombay blood group, also called hh, is deficient in expressing antigen H, meaning the RBC has no antigen H. Thus, in hh, there are no A or B antigens, so they are similar to O group. But they alos lack H antigen, hence called Bombay blood group. Could be D positive or negative.

Blood type A is the most ancient, and it existed before the human species evolved from its hominid ancestors

Rarest blood type?

• AB-negative (. 6 percent)
• B-negative (1.5 percent)
• AB-positive (3.4 percent)

O+ is the most frequently occurring blood type and is found in 37 percent of the population. O- is found in six percent of the population

O positive donors who are CMV negative are known as Heroes for Babies at the Red Cross because it is the safest blood for transfusions for immune deficient newborns

Of the eight main blood types, people with type O have the lowest risk for heart disease. People with types AB and B are at the greatest risk

• People with A and AB blood have the highest rates of stomach cancer.

Type O individuals may be more likely to develop peptic ulcers caused by Helicobacter pylori bacterium than other blood types, and that type O women may have more risk of fertility problems

The golden blood type or Rh null blood group contains no Rh antigens (proteins) on the red blood cell (RBC). This is the rarest blood group in the world, with less than 50 individuals having this blood group

Rh incompatibility - If a woman who is Rh negative and a man who is Rh positive have a baby, the fetus may have Rh-positive blood, inherited from the father. Rh incompatibility usually isn't a problem if it's the mother's first pregnancy because the baby's blood does not normally enter the mother's circulatory system. During the birth, the mother's and baby's blood can mix. The mother's body recognizes the Rh protein as a foreign substance and begin making antibodies  against the Rh protein.Rh antibodies are harmless until the mother's second or later pregnancies. If she is next carrying another Rh-positive child, her Rh antibodies will recognize the Rh proteins on the surface of the baby's blood cells as foreign. Her antibodies will pass into the baby's bloodstream and attack those cells. This can make the baby's red blood cells swell and rupture. This is known as hemolytic or Rh disease of the newborn.