Back ground: Severe anaemia is associated with negative impact on both the mother and the newborn. Foetal anaemia, low birth weight, preterm birth and still birth have been associated with anaemia. Women with iron deficiency are particularly susceptible to iron deficiency anaemia during pregnancy. Apart from that there was no consistency in the timing of haemoglobin considered for analysis. So we designed a study to look into these aspects. Material and methods:The study was carried out in obstratics and gynaecology department of B. J. Medical College, Ahmedabad. A total number of 105 pregnant women, attending OPD were taken. 90 of them registered for antenatal clinic in the first trimester. The remaining 15 reported for registration only in 3 rd trimester. Blood was collected from all the subjects to measure the haemoglobin concentration between 16-18 weeks, 22-24 weeks and 34-36 weeks of pregnancy. Hematocrit and RBC were measured between 34-36 weeks and all the haemoglobin indices were calculated. Results: The prevalence of anaemia among pregnant women in this study was 71.43% with severity of anaemia higher in age between 25-30 years. The severity of anaemia that developed in the last trimester was closely related to haemoglobin levels found in the first trimester. Conclusion:The hematocrit, RBC count and haemoglobin indices were lower in women who did not received iron supplementation which was highly significant. Iron supplementation decrease the fall as compared to the group without iron supplementation. Antenatal care should be made available to pregnant women in both urban and rural areas.