Iron status of pregnant women at different stages of pregnancy was evaluated by comparing values for hemoglobin (Hb), red cell indices, serum iron (SI), transferrin saturation (TS) and serum ferritin (SF) values with those of a group of non-pregnant women of comparable age and socio-economic status. Mean SF values on the second and third trimesters (9.3 +/- 2.60 ng/ml and 7.1 +/- 2.19 ng/ml) were significantly lower compared to that in the first trimester (22.6 +/- 2.20 ng/ml). These levels were also lower than that found in the non-pregnant controls. The trend was the same for TS. Hemoglobin levels of the pregnant subjects were significantly lower than those of the non-pregnant women. Prevalence of iron deficiency based on SF < 12.0 ng/ml and TS < 16.0% was highest at term and lowest during the first trimester indicating a decrease in iron stores as pregnancy progressed. Sensitivity for each of the iron parameters was computed, and it was found that for the diagnosis of iron deficiency in pregnant women, SF has a greater sensitivity than TS, SI, MCV and MCH.