Objective:To assess the prevalence of anemia and asymptomatia malaria parasitemia and the effect of prior antimalarials therapy on the parasite density in pregnant women at their first antenatal visit at the secondary level health care facility in Nigeria.Methods:This cross sectional observational study was carried out in the antenatal clinic of General Hospital,Ikot Ekpene,Akwa Ibom State,Nigeria for 3 months period(1~(st) June to 31~(st) August,2009).Five hundred and fourteen women attending their first antenatal registration visits in the hospital were recruited in the study.Socio-demographic information was obtained using pre-tested questionnaires.The malaria parasite was obtained by examining thick and thin blood films prepared on 2 glass slides while the hematocrit was obtained through 2 capillary tubes read by a Hawksleys microhematocrit reader.Results:A total of 514 pregnant women participated in the study with a mean maternal age of 21.4 years and a mean gestational age at booking of 18.3 weeks.The primigravid women booked at significantly lower gestational age than multigravidae (16.2 weeks vs 21.6 weeks).Most of the women(59.3%) were anemic,out of which 60.4%were primigravida.More than half of the women had moderate to high parasite density and only 6.8% had no malaria parasitemia.All patients with severe anemia were parasitemic.Out of the 479 (93.2%) women with parasitemia,a third had taken antimalarial drugs.A majority(60.3%) of those without prior antimalarial drugs had moderate to high density parasitemia.Conclusions: This study shows high prevalence of anemia in women with asymptomatic malarial parasitemia, particularly the primigravida.The severity of anemia is directly related to the density of malaria parasitemia.Those with effective antimalarial therapy appear to have low density parasitemia and therefore mild anemia.Routine screening for anemia and malaria parasites at booking,prompt parasite clearance and correction of anemia would reduce the associated maternal and perinatal complications. Objective: To assess the prevalence of anemia and asymptomatia malaria parasitemia and the effect of prior antimalarials therapy on the parasite density in pregnant women at their first antenatal visit at the secondary level health care facility in Nigeria. Methods: This cross sectional observational study was carried out in the antenatal clinic of General Hospital, Ikot Ekpene, Akwa Ibom State, Nigeria for 3 months period (1 st-June to 31-st August, 2009) .Five hundred and fourteen women attending their first antenatal registration visits visits in the hospital were recruited in the study. Ocio-demographic information was obtained using pre-tested questionnaires. The malaria parasite was obtained by examining thick and thin blood films prepared on 2 glass slides while the hematocrit was obtained through 2 capillary tubes read by a Hawksleys microhematocrit reader. Results: A total of 514 pregnant women participated in the study with a mean maternal age of 21.4 years and a mean gestational age at boo king of 18.3 weeks.The primigravid women booked at significantly lower gestational age than multigravidae (16.2 weeks vs 21.6 weeks) .Most of the women (59.3%) were anemic, out of which 60.4% were primigravida .More than half of the women had moderate to high parasite density and only 6.8% had no malaria parasitemia. All patients with severe anemia were parasitemic. Of the 479 (93.2%) women with parasitemia, a third had antimalarial drugs. A majority (60.3%) of those without prior antimalarial drugs had moderate to high density parasitemia. Conclusions: This study shows high prevalence of anemia in women with asymptomatic malarial parasitemia, particularly the primigravida. severity of anemia is directly related to the density of malaria parasitemia. Those with effective antimalarial therapy appear to have low density parasitemia and therefore mild anemia. Routine screening for anemia and malaria parasites at booking, prompt parasite clearance and correction of anemia would reduce the aassociated maternal and perinatal complications.