The aetiology of anaemia during pregnancy: a study to evaluate the contribution of iron deficiency and common infections in pregnant Ugandan women

Objective: To describe the aetiology of anaemia in pregnant Ugandan women and explore Fe deficiency and common infections as contributors to anaemia in this population. Design: Cross-sectional study in which Hb, ferritin, transferrin receptor (sTfR), C-reactive protein, alpha-1 acid glycoprotein, hepcidin, malaria, hookworm infestation, syphilis and Helicobacter pylori infection were assessed. Setting: Antenatal care clinic at Kawempe Health Centre, Kampala, Uganda. Subjects: HIV-negative women (n 151) in their first or second pregnancy at 10-16 weeks' gestation. Results: The prevalence of anaemia was 29.1 %. Fe deficiency was 40.4 % and 14.6 % based on ferritin <30 mu g/l and on adjusted ferritin <12 mu g/l respectively, and 6.6 % based on sTfR >8.3 mu g/ml. The prevalence of Fe-deficiency anaemia was 9.3 % based on ferritin <30 mu g/l, 6.6 % based on adjusted ferritin <12 mu g/l and 4.3 % based on sTfR >8.3 mu g/ml. Hepcidin concentration was positively correlated with ferritin concentration (n 151, r=0.578, P<0.00001). H. pylori infection was highly prevalent (70 %) while malaria, hookworm infestation and syphilis were not common. Of all women, 60.3 % had alpha-1 acid glycoprotein >1 g/l and/or C-reactive protein >5 mg/l. Malaria parasitaemia (OR=6.85; 95 % CI 1.25, 37.41, P=0.026) and Fe deficiency defined using sTfR (OR=5.58; 95 % CI 1.26, 24.80, P=0.024) were independently and positively associated with anaemia. Population-attributable risk factors for anaemia for raised C-reactive protein, Fe deficiency defined by sTfR >8.3 mu g/ml and presence of malaria parasites were 41.6 (95 % CI 11.1, 72.2) %, 13.5 (95 % CI 2.0, 25.0) % and 12.0 (95 % CI 1.4, 22.6) %, respectively. Conclusions: Infections and inflammation are of greater significance than Fe deficiency in the aetiology of anaemia in pregnant Ugandan women during the first trimester.