An analysis of the determinants of anaemia in pregnant women in rural Malawi - a basis for action

Haematological data are presented on 4104 pregnant women attending the ante natal-care facilities of two hospitals in a rural area in southern Malawi. In this area, malaria transmission is perennial and there is a high prevale nce of HIV infection. The local women are exposed to drought and food short ages but experience high fertility rates. Mean (S.D.) haemoglobin (Iib) concentration was significantly lower in the primigravidae [8.7 (1.6) g/dl] than in the secundigravidae [9.1 (1.5) g/dl; P<0.0001] or multigravidae [9.2 (1.5) g/dl; P<0.0001]. Primigravidae also experienced significantly more iron deficiency and malaria than secundi- or multi-gravidae. For all parity groups, the lowest mean Hb levels were obse rved between 26-30 weeks' gestation. In primigravidae peak prevalence of ma laria occurred between 16-20 weeks' gestation (38.6%) and peak prevalence o f moderately severe anaemia (<8 Hb/dl) between 26-30 weeks' (35.7%). Multig ravidae showed little variation in the prevalence of anaemia, iron deficien cy and malaria with gestational age. Peak prevalences of malaria were obser ved in April, in the post-rainy season, with values of 51.4%, 56.0% and 25. 3% for primi-, secundi- and multi-gravidae, respectively. Peak prevalences of iron deficiency occurred between April and May and those of moderately s evere anaemia between May and June. Mean Hb was lower in adolescent primigr avidae than in any other group of pregnant women [8.6 (1.5) g/dl], includin g the non-adolescent primigravidae [8.9 (1.6) g/dl; P = 0.008]. Other facto rs significantly associated with increased risk of moderately severe anaemi a in primigravidae were illiteracy and poor nutritional status (i.e. body m ass index <18.5 kg/m(2) and mid-upper-arm circumference < 23 cm). After for ward, step-wise, regression analysis of relative risk (RR) factors and thei r 95% confidence intervals (CI), variables associated with an increased ris k for moderately severe anaemia were if on deficiency (RR 4.2; CI = 3.0-6.0 ) and malaria parasitaemia (RK = 1.9; CI = 1.3-2.7) in primigravidae, iron deficiency (RR = 4.1; CI = 2.7-6.3) and mid-upper-arm-circumference <23 cm (RR = 1.8; CI = 1.1-3.0) in secundigravidae, and iron deficiency in multigr avidae (RR = 3.1; CI = 4.3-6.9). The basis of anaemia prevention in this population of pregnant women is mal aria control and haematinic supplementation, one of the most serious drawba cks being non-compliance. Although the present data are presented according to the World Health Organization's definitions of anaemia, the correspondi ng cut-off values for Hb (<11 or <7 g/dl) were not associated with malaria, suggesting that these III, levels would be less useful indicators in malar ia interventions. It is argued that an Hb value of < 8 g/dl might be consid ered for identifying the pregnant women at highest risk, for selective heal th education to reduce non-compliance.