In this study, we evaluated the effect of pregnancy on some haematological parameters among 600 apparently healthy pregnant Ijaw women attending antenatal clinic at the Federal Medical Centre, Yenagoa, Nigeria. Each trimester consisted of 200 subjects. Another age-matched 200 apparently healthy non-pregnant adult females served as control. All subjects were between 18-40years. The results showed significant decrease in PCV and Hb among the pregnant women in the first, second and third trimesters when compared with the control subjects (p<0.05). There was also a significant decrease in the platelet count and lymphocyte count among pregnant women in the second and third trimesters when compared with the controls (p<0.05). But there was a significant increase in ESR and neutrophil count among pregnant women in the first, second and third trimesters when compared with the control subjects (p<0.05). There was also a significant increase in the total WBC among pregnant women in the second trimester when compared with the controls (p<0.05). There was no significant difference in the monocytes and eosinophils count between the pregnant women in all the three trimesters and the female controls (p>0.05). Also, there was no significant difference in the total WBC, platelet and lymphocyte count among pregnant women in their first trimesters when compared with the control subjects (p>0.05). A normal reference range has been established for pregnant women of Ijaw transient so as to enhance proper assessment and management of antenatal cases. Keywords: Evaluation, haematological parameters, pregnancy, Ijaw tribe
