Lymphocytes are a type of white blood cells in the blood. They are structured to fight against strangers like bacteria, viruses. Normally they do not see the baby as a stranger and attack it. But in some women, lymphocytes change their rates, their functions are confused and begin to see the embryo as a threat. They produce secretions against the embryo and begin to attack it. Because the embryo is the joint product of the mother and father. The half coming from the father is foreign to the mother. Therefore, it is considered that in the case of recurrent pregnancy loss, in cases where implantation is problematic, there may be a rejection reaction in the mother that we can define as being allergic to the father’s cells. At the same time, the system functioning for acceptance may also have a failure.