Anaemia in young Primigravidae in the guinea savanna of Nigeria: sickle-cell trait gives partial protection against malaria

Haematological indices, malarial parasitaemia, serum and red cell folate (SFA, RCF), serum vitamin B12 and haemoglobin (Hb) electrophoretic patterns were studied in 228 non-elite young Hausa primigravidae at less than 24 weeks of gestation. The study was conducted in the guinea savanna of Nigeria, where malaria is hyperendemic. Ninety-nine (43%) were anaemic (Hb less than 11.0 g dl-1). The commonest cause of anaemia was malaria, in 28% of all and 40% of anaemic subjects. Plasmodium falciparum was predominant; P. malariae was seen in 1.3% and P. ovale was not recorded. Parasitaemia was more frequent and more dense in the wet than the dry season. Iron deficiency was diagnosed in 18% of all and 25% of anaemic women; 14% of all patients were folate-deficient; high MCV and MCH correlated with anaemia, and low SFA was associated weakly with anaemia and malaria. Serum vitamin B12 was normal or high in all 145 in whom it was measured; 3% had congenital elliptocytosis, but this did not contribute to the anaemia. Sickle-cell trait was present in 26% and Hb-AC in less than 1%. Hb-AS was associated with significantly lower frequency and density of P. falciparum; this has not been demonstrated in pregnancy in Africa previously. However, the parasitological advantage was not reflected in any haematological advantage. The roles of malaria, folate-deficiency and iron-deficiency in the causation of anaemia in Hausa primigravidae will be defined further by a double-blind trial of antimalarial prophylactics, iron supplements and folic acid supplements.