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Objective To determine prevalence of anaemia in pregnancy in southern Malawi, and to establish if an ‘at risk’ group can be identified for targeted intervention.
Design Prospective cross-sectional study.
Setting A semi-urban hospital and a rural health clinic in southern Malawi.
Population Pregnant women attending the antenatal clinic for their booking visit.
Methods Haemoglobin concentration (g/dL) measured from a capillary blood sample (fingerprick) by battery operated HemoCue machine.
Results In urban Blantyre 57% of women were anaemic by WHO standards (haemoglobin < 11.0 g/dL) and 3.6% were severely anaemic (haemoglobin < 7.0 g/dL). The prevalence was higher in the rural area; 72% and 4.0%, respectively. Primiparae were at slightly increased risk for overall anaemia and severe anaemia but the effect of targeting this group alone for interventions would mean at least 65% of anaemic women and over half of the women with severe anaemia would be excluded. When the effect of age was examined separate from gravidity, adolescents were not found to be at increased risk of anaemia. Anaemia was more prevalent in the wet season and in women who booked late for antenatal care.
Conclusion The prevalence of anaemia in pregnancy in our population is unacceptably high and deserves more attention. Prophylaxis of all women rather than an ‘at risk’ group based on age or gravidity is recommended.
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Anaemia in pregnancy, particularly severe anaemia, is associated with an increased risk of maternal mortality1–3, which, in most developing countries, continues to be unacceptably high4–6. In 1993, the World Bank ranked anaemia as the eighth leading cause of disease in girls and women in developing countries7.
In Africa, the prevalence of anaemia in pregnancy is estimated to be 35% to 75%8. The actual prevalence rates for many individual countries is however not known. At the African Regional Consultation on the Control of Anaemia in Pregnancy (1989), it was recommended that simple studies of prevalence and aetiology should be undertaken for each region. In the last published tabulations from the WHO Maternal Health and Safe Motherhood anaemia database (1992), estimates for the region of South East Africa were based on a total sample of about 10,000 women with only one (unpublished) study from Malawi reporting the outcome of screening 319 women8. Up-to-date information from most countries is still scanty; the few published studies describe small samples and are usually from hospital-based populations. There is a lack of data from rural areas. It has been suggested that the prevalence of anaemia may depend on the season, increasing in relation to malaria in the wet season, or in relation to food shortage at the end of the dry season9. Published prevalence rates almost never reflect measurements performed all year round.
In a review of epidemiological criteria for the assessment of severity and magnitude of anaemia in pregnancy, the following categories were proposed: mild anaemia (haemoglobin 9.0–10.9 g/dL), moderate-to-severe anaemia (haemoglobin 7.0–8.9 g/dL) and severe anaemia (haemoglobin < 7.0 g/dL)10. This is in accordance with the WHO definitions of anaemia in pregnancy, which are: overall anaemia (haemoglobin < 11.0 g/dL) and severe anaemia (haemoglobin < 7.0 g/dL)1. In areas with high prevalence programmes for the control of anaemia can be expected to reduce the prevalence of severe anaemia and moderate-to-severe anaemia. Prevalence of overall anaemia and mild anaemia might initially remain unchanged.
Most sub-Saharan countries, including Malawi, currently have national policies to prevent and treat anaemia in pregnancy. These include the provision of haematinics and malarial prophylaxis for all pregnant women. Despite a lack of information about prevalence before and after the implementation of many such programmes, a general disappointment with the persistently common problem of anaemia in pregnancy has been expressed1,2,11,12. It has been suggested therefore that interventions should be more focused. Suggested target groups have been: women with severe anaemia2, adolescents13,14, primi-gravidae15,16 or conversely multigravidae13,17. However, there are insufficient data to indicate which group can rightly be identified as being particularly at risk of anaemia overall or severe anaemia. We need to estimate the baseline prevalence of anaemia to determine the possible effectiveness of target prophylaxis.
In this paper we examine the distribution of haemoglobin values obtained by screening women at their first antenatal clinic attendance. The percentages of women with anaemia (haemoglobin < 11.0 g/dL) and severe anaemia (haemoglobin < 7.0 g/dL) were determined and compared in a semi-urban and a rural population and at different times of the year. In an attempt to identify a ‘risk group’, univariate and multivariate logistic regression was performed to determine the relative risk of age, gravidity, trimester and season for anaemia overall and for severe anaemia.