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Impact of Malaria during Pregnancy on Low Birth Weight in Sub-Saharan Africa Malaria during pregnancy can result in low birth weight (LBW), an important risk factor for infant mortality. This article reviews the pathological effects of malaria during pregnancy and the implications for the newborn's development and survival. Empirical data from throughout Africa on associations between placental malaria and birth weight outcome, birth weight outcome and infant mortality, and the rates of LBW in areas with various levels of malaria transmission are evaluated to assess the increased risks of LBW and infant mortality associated with malaria. It is estimated that in areas where malaria is endemic, around 19% of infant LBWs are due to malaria and 6% of infant deaths are due to LBW caused by malaria. These estimates imply that around 100,000 infant deaths each year could be due to LBW caused by malaria during pregnancy in areas of malaria endemicity in Africa. It is estimated that each year over 30 million women become pregnant in malarious areas of Africa, with most living in areas of stable malaria transmission (92). Although the vast majority of women with malaria infections during pregnancy remain asymptomatic, infection increases the risk of maternal anemia and delivering a low-birth-weight (LBW) baby. LBW ( 2,499 g) (41). Proportions of LBW and normal birth weight (NBW) babies dying in the first month and the first year of life in sub-Saharan Africa. Thick lines represent the medians, boxes represent the interquartile ranges, and I bars represent the ranges of data points. (Reprinted from reference 26 with permission of the publisher.) LBW can be due to prematurity or IUGR. Identifying LBW cases caused by prematurity can be difficult, as many African women are not certain of their gestational age; as a result, very few studies report separately data on LBWs for preterm infants and those for infants with IUGR. It was previously thought that malaria mostly affects IUGR (11), though recent work has shown malaria to also be important in prematurity (47, 57). This finding has important implications for the impact on mortality, as preterm infants with LBW have been shown to be at a higher risk of dying than those with IUGR, custom essay writing service blogger dashboard problems with internet least in developed countries (34). LBW is also a well-documented risk factor for poor neurosensory, cognitive, and behavioral development, as well as for limited school performance and academic achievement (46, 81, 82). Most of the studies concerned with these factors have been conducted in developed countries, and many have focused on very LBW (usually less than 1,001 g). However, the most vulnerable group appears to be those infants born prematurely, who will be two to four times more likely to experience failure in school than infants of normal birth weight and will need specialist support or educational services (27). Most studies find primigravidae to have a higher prevalence of P. falciparum infection than women of higher gravidities and to be at higher risk of adverse outcomes. Sera from multigravid women in their third or later pregnancy, but not sera from primigravidae, can often agglutinate parasites from the placenta, suggesting that exposure to these isolates does not occur prior to pregnancy but that variant-specific immune responses develop following exposure during pregnancy (5). The risk of placental malaria and its associated morbidity with gravidity have been exploited in the development of a birth weight nomogram (12), where malarious areas and zones of malaria transmission are based on odds ratios for an excess of LBW infants for primigravidae compared with those for multigravidae. Any outliers, i.e., sites with a low odds ratio resulting from a high risk of LBW infants for multigravidae, are assumed to occur because those residing in low transmission areas have not acquired significant antimalarial immunity or because they are exposed to a high risk of human immunodeficiency virus (HIV) (12). Although a Cochrane meta-analysis of randomized controlled trials suggested that the benefit of preventing malaria during pregnancy is limited to primigravidae (24), a recent analysis of the approach used in that analysis suggests that this conclusion may have been incorrect (28). Other intervention studies not included in the Cochrane review have shown benefits in women of all gravidities (11, 61, 87), with protective efficacies of around 50%. There would be obvious operational problems of limiting treatment to primigravidae only, with the added concern that all women infected with HIV would benefit from treatment (83). Although maternal parasitemias have been used routinely to detect malaria during pregnancy, it is recognized that peripheral parasitemias may remain below the levels of microscopic detection while parasites are harbored by the placenta (68). Histological examination of the placenta is the most sensitive indicator of maternal infection (68). Examination can show signs of active infection (presence of infected erythrocytes in the intervillous space), past or chronic infection (malarial pigment), or both. Cross-sectional data on the associations between placental malaria infection and birth weight outcome have been collected for all gravidity groups since the late 1940s. A previous analysis showed that a baby is twice as likely to be born with a LBW if the mother has an infected placenta at delivery (26). This finding held true both for primigravidae only and for all gravidities. It was based on data from 14 studies from five countries dating from 1948 to 1998, with four of the studies excluding preterm births. Since this analysis, a number of new studies have been published; Table 1 summarizes the associations found between placental malaria and LBW in studies conducted since 1980 of random samples of births (preterm and full-term) from facilities in areas of stable malaria transmission. Data from intervention trials (14, 15, 77) and from areas of unstable malaria transmission (17, 55) were excluded. Studies that assessed infection only through maternal peripheral smears (65, 80) or did not differentiate between peripheral and placental infection (8) were also excluded. Remaining were 4 studies for primigravidae and 11 studies for all gravidities (Table 1). Increased risk of LBW associated with help writing my paper the great gatsby by scott f. fitzgerald infection in stable transmission areas a. Despite the prevalence of placental infections for women of all gravidities, ranging from 5 to 52%, the risk of LBW associated with infection was relatively consistent, with babies born to mothers with an infected placenta being twice as likely to be of LBW than those born to mothers with an uninfected placenta (median prevalence ratio, 2.06) (Table 1). The prevalence ratio appears to be unaffected by the prevalence of placental malaria, and therefore for purposes of attributable fraction analysis the median value is used. This value suggests that approximately half of the LBW cases among those infected with placental malaria are due to malaria (the infected attributable fraction). Given a median prevalence of placental malaria of 26%, the population-attributable fraction (the percentage of all LBW cases due to malaria) is estimated to be 19% (Table 1). In other words, one-fifth of the LBWs of babies born to mothers in areas where malaria is endemic are due to malarial infection of the placenta while the mother is pregnant. This compares to previous estimates of between 8 and 14% (79). Although the prevalence of placental malaria infection may provide an indication of the risk of malaria transmission, a more widely used marker of malaria endemicity is the prevalence of P. falciparum infection in a given childhood population (73). Professional persuasive essay ghostwriters services is often termed the parasite rate, and this information is available for many sites throughout sub-Saharan Africa, often from research projects undertaking community-based surveys. Independent of this information are data on the prevalence of LBW, which are often routinely collected at hospitals. The purpose of this section is to combine these independently collected data on LBWs and parasite rates for sites across the African continent. LBW Data A literature search was undertaken for birth weight data in sub-Saharan Africa by using MEDLINE and CAB HEALTH databases with “birthweight” and “Africa” as the search keywords. The major tropical journals were also checked for possible data sources by manual searches of issues with predigital dates. The bibliographies of all papers collected were checked for additional references. Studies were included in the analysis only if they were undertaken post-1980, as for previous burden estimates (75), and did not exclude preterm births from those sampled. Since 1976, LBW was universally classified as 75%) matching logarithmic increases in the entomological inoculation rate ( 100 infective bites per adult per year) (6, 73) (Table 3). Although there is a general trend for the prevalence of LBWs to increase with increasing malaria risk, the only clear and marked difference is observed when top custom essays ukraine capital ukrainian barbie dolls risks of greater cheap write my essay who changed my life less than 25% are being compared. Differences in the prevalences of LBW with malaria risk at levels greater than 25% are inconclusive, partly due to the paucity of data at high malaria risk levels. Even a marked relationship may not be causal but may simply reflect the association of malaria risk and LBW with other underlying factors (such as poverty) that determine both malaria risk and LBW. However, recent data from an insecticide-treated bed net trial in Kenya has provided important evidence that a reduction in the rate of malaria transmission can reduce the prevalence of LBW, with even greater reductions expected than those observed, given the anticipated reductions in the control arm through the effects of mass killing of mosquitoes (83). The lack of a clear relationship between the independently collated data on LBW and parasite prevalence from 44 sites across Africa is not surprising given the possible variations in the parasite rate by age group and season, essay help online paper help contact us 1 855 206 3787 our address other factors, and the expected heterogeneity across sites in factors which may affect LBW, such as altitude and HIV status. Median prevalences of LBWs at different levels of malaria endemicity. The interactions between HIV a problem by anton chekhov essay malaria during pregnancy are complex. Studies in Kenya and Malawi have shown that the prevalence and density of malaria parasites are higher in pregnant women who are also HIV positive (59, 78, 88). The risk of infants dying during the postneonatal period has also been shown to be 3.4-fold higher in children born to HIV-positive mothers with placental malaria than in those born to HIV-positive mothers without placental malaria (9). It has been demonstrated in some studies that HIV alters the patterns of malaria during pregnancy so that women of all gravidities are at the same level of risk, with get someone write my paper families should attempt to live without television implication that prevention strategies need to be targeted to all pregnant women (86). The current recommended preventive therapy for malaria during pregnancy is the drug sulfadoxine pyrimethamine (SP), given in two doses for intermittent preventive treatment in the second and third trimesters. However, HIV also has an impact on the efficacy of SP, and it has been suggested that at least three doses of SP may be required for HIV-positive women (59). Malaria may also worsen HIV infection, with a recent study in Blantyre, Malawi, indicating that malaria may increase the HIV load in adults (31). In addition, concerns that malaria infection of the placenta may contribute to mother-to-child HIV transmission remain (9, 13). LBW is influenced by many factors, including genetics, multiple pregnancies, placental abnormalities, maternal nutrition, maternal age, gravidity, and history of smoking, and a range of viral, bacterial, and parasitic infections. Malaria is unique in being one of the few problems that is amenable to intervention once a woman becomes pregnant. Although the relationship between LBW and child survival has been recognized for several decades (45), surprisingly little attention has been paid to preventing LBW as a mortality reduction strategy (67). The first hurdle is to establish just how many infant deaths could be prevented. The Africa Malaria Report states that malaria during pregnancy is estimated to cause between 75,000 and 200,000 infant deaths per year (92), and other estimates (by Murphy and Breman [53]) are between 62,000 and 363,000. Using two different approaches, we estimate that around 100,000 infant deaths in areas of Africa where malaria is endemic could be due to malaria during pregnancy causing LBW (Fig. 2). Number of infant deaths due to malaria during pregnancy in areas of stable malaria risk in sub-Saharan Africa. Population of live births refers to number of live births in areas at risk for stable endemic malaria in 2000, as estimated from maps of malaria risk and population models (74). The infant mortality rate is a summary of the rate for sub-Saharan African in 2001 (85). The percentage of infant deaths was determined by using the formula and data on mortality risks presented by Guyatt and Snow (26) with the following revised probabilities based on the new data in Table 1: 0.257 for placental malaria infection (PI), 0.262 for LBW given placental infection (qLBW; range, 0.228 to 0.309), and 0.137 for LBW given no placental infection (range, 0.117 to get someone write my paper families should attempt to live without television. It is estimated that 5.68% (range, 3.69 to 8.77%) of infant deaths are due to malaria-induced LBW. The percentage of LBW infants in areas of malaria endemicity is 17%, the median of the results of 11 studies presented in Table 1. This figure is supported by the data from 31 studies which reported a malaria risk of >25% (Table 2), with a median LBW of 16.4%. The percentage of LBW infants due to malaria during pregnancy is 19% (range, 14 to 25%), which is the population-attributable fraction from Table 1. The percentage of LBW infants dying in the first year of life is 16.2%, based on the mortality risk of 0.162 in five studies reported by Guyatt and Snow (26). Both estimates use as their foundation the 17,765,000 live births buy essay online cheap internship report on milkvita each year in areas of stable malaria risk in Africa (74). The first approach uses the model described by Guyatt and Snow (26) and revised estimates on the risks of LBW with and without placental infection, and the risks of placental infection from the data in Table 1, to determine that 5.68% (range, 3.69 to 8.77%) of infant deaths are attributable to LBW caused by malaria. Assuming that there are 1,900,855 infant deaths (from the base population of live births and an infant mortality rate of 107/1,000 births (85) (see Fig. homework help online employer means in areas of malaria endemicity in Africa suggests that 107,969 (range, 70,142 to 166,705) of the infant deaths may be attributable to malaria during pregnancy. The second estimate uses the population-attributable fraction (19% [range, 14 to 25%] of LBWs being due to malaria during pregnancy) shown in Table 1 and applies this fraction to the population of LBW infants paper writers online acceptance page areas of stable malaria risk in Africa. It is estimated that 573,800 (range, 422,800 to 755,000) infants have LBWs due to malaria during pregnancy, and modifying this result with a probability of dying from a LBW in the first year of life of 0.162 (26) yields 92,956 (range, 68,494 to 122,310) infant deaths as a result of malaria-induced LBWs. LBWs due to malaria may result from IUGR or premature delivery. In a recent review of measures for preventing child mortality, malaria during pregnancy was identified as an important factor in precipitating preterm delivery, one of the nine main causes of death in children under 5 years of age (36). Antimalarial intermittent preventive treatment during pregnancy was estimated to prevent 22,000 deaths of children under 5 years of age through reduced numbers of preterm deliveries, which is Akogbeto, M., D. Modiano, and A. Bosman. 1992. Malaria transmission in the lagoon area of Cotonou, Benin. Parassitologia 34 : 147 -154.

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