Infections, nutritional deficiencies, bone marrow disorders, some cancers and polycythemia can all affect different aspects of a woman's blood count test, according to Brigham and Women's Hospital. Ordinary menstruation can also affect a woman's blood count, and women tend to have a lower overall red blood cell count than men due to blood loss during their periods.
A typical blood count test assays the number of red blood cells, white blood cells and platelets in a person's blood, notes Brigham and Women's Hospital. Blood counts also assess the level of the oxygen-carrying protein hemoglobin in the blood as well as a person's hematocrit, defined as the percentage of red blood cells in the blood by total blood volume. Different diseases and conditions cause different changes in a woman's blood count depending on the exact condition. For example, a rise in white blood cell count often indicates infection or inflammation of some kind, while a drop in white blood cell count may indicate certain cancers, bone marrow issues, liver problems or lupus.
A drop in red blood cell count severe enough to qualify as anemia is sometimes seen in women with heavy menstrual bleeding, according to the Centers for Disease Control and Prevention.