Low lymphocytes in pregnant women can be caused by a viral infection of the respiratory tract, resulting in low lymphocytes in the pregnant woman. Or when a pregnant woman’s own immune system is low, this can also cause her lymphocytes to be low. Lymphocytes may be physiologically mildly low when a woman is tested during pregnancy. Pregnant women can also have low lymphocytes in their bodies following the use of medications such as adrenal hormones. Exposure to radioactive light may also cause low lymphocytes in the patient’s body. If the total number of white blood cells, neutrophil percentage and other cells in the routine blood test are not significantly abnormal, and there is no significant abnormality in the pregnant woman’s body, mild hypolymphocytes can be observed and followed up, and the pregnant woman does not need special treatment. If there are abnormalities in other cells in the blood count, further tests are needed to clarify the diagnosis.