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

Abstract

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 <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 < 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.