Background: The hematologic system undergoes a series of adaptive changes in preparation for fetal hematopoiesis and wellbeing while also serving as a cushion against expected blood loss at delivery. Objectives: The aim of the present review was to high light on the haematological disorders during pregnancy in pregnant women. The haematological changes during pregnancy are range from the increased plasma volume and red blood cell mass, leucocytosis and adaptive immunological changes to the relative hypercoagulable state of pregnancy. The increase in total blood volume at term, serves as a reserve against normal blood loss at delivery and peripartum hemorrhage. Anaemia is the most common hematological problem in pregnancy, followed by thrombocytopenia. Hemoglobin level below 11g/dl in pregnant women constitutes anemia and hemoglobin below 7g/dl is severe anemia. Up to 56% of all women living in developing countries are anemic. About 20 % of maternal deaths occur due to anaemia. The most common causes of anaemia in pregnancy include iron deficiency, folate deficiency, vitamin B12 deficiency, hemolytic diseases, bone marrow suppression, chronic blood loss and underlying malignancies. Prevalence of several maternal risk factors which are associated with low birth weight, increased perinatal, maternal morbidity and mortality are higher among anaemic women. Also, leukocytosis is almost always associated with pregnancy. A pregnancy related leukocytosis with an increase in neutrophils has been seen from the second month of pregnancy with an upward trend observed as pregnancy advances. Lymphocyte count was decreased in pregnant women. 10% lower platelets level at term compared with at pre-pregnancy . The mechanisms for this are thought to be due to dilution effects and accelerated destruction of platelets passing over the often scarred and damaged trophoblast surface of the placenta. 75% of cases of platelets changes are due to gestational thrombocytopenia, 15%–20% seconda