Blocking antibodies are antibodies that are produced in the mother’s intrinsic serum after conception against the lymphocytes of the spouse, which inhibit the lymphocyte response and prevent the mother’s immune system from rejecting the fetus. There is a protective antibody that facilitates the growth and development of the fetus and is produced by most women. Failure to produce this antibody after pregnancy can attack the embryo and placenta and can cause a miscarriage. After testing, this antibody cannot be detected in 90% of women who have spontaneous abortion. The main method of treatment is through cellular immunotherapy, which allows the body to produce this antibody and is more difficult to treat, so it is recommended to go to a large tertiary hospital for treatment.