VA Â» Office of Public and Intergovernmental Affairs Â» History of Veterans Day. World War I â known at the time as âThe Great Warâ - officially ended when the Treaty of Versailles was signed on June 28, 1919, in the Palace of Versailles outside the town of Versailles, France.
If your blood mixes with Rh-positive blood, your immune system will react to the Rh factor by making antibodies to destroy it. This immune system response is called Rh sensitization. Rh sensitization can occur during pregnancy if you are Rh-negative and pregnant with a developing baby (fetus) who has Rh-positive blood.
If your blood lacks the Rh antigen, it is called Rh-negative. If it has the antigen, it is called Rh-positive. When the mother is Rh-negative and the father is Rh-positive, the fetus can inherit the Rh factor from the father. This makes the fetus Rh-positive too. Problems can arise when the fetusâs blood has the Rh factor and the motherâs blood does not.