PREVALENCE AND DETERMINANTS OF ANAEMIA IN PREGNANT WOMEN ATTENDING ANTENATAL CLINIC IN JOS, PLATEAU STATE, NIGERIA.

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PREVALENCE AND DETERMINANTS OF ANAEMIA IN PREGNANT WOMEN ATTENDING ANTENATAL CLINIC IN JOS, PLATEAU STATE, NIGERIA.

ABSTRACT

Anaemia in pregnancy is a common problem in the developing countries. It is a major cause of morbidity and mortality, with 20% of maternal deaths in Africa being attributable to this problem.

This study was carried out to determine the prevalence and the determinants of anaemia among pregnant women who presented to book for antenatal care at the Fillin Ball PHC in Jos North LGA of Plateau State. The women were enrolled during their booking clinic. Most of them presented after the first trimester of their index pregnancy, with more women booking during the third trimester than in the first. During the booking clinic, socio-demographic data, past medical history and history of the index pregnancy were collected using a questionnaire. Samples of venous blood, urine and stool were collected from the women. The venous blood was tested for RBC indices, serum ferritin, and the presence of malaria parasite. Urine sample was tested for urinary tract infection and the stool sample was tested for intestinal parasites. The women also received a routine physical examination and findings were recorded.

One hundred and nineteen (46.7%) of the subjects were found to be anaemic with most (59.7%) having mild anaemia. The prevalence of iron deficiency was very high (65.1%) in the study subjects. There was a high prevalence of malaria (40.4%) among the study subjects and 41.2% of them had a UTI based on urine culture findings. The prevalence of HIV infection and intestinal parasitic infections were low, 2.0% and 9.0% respectively. All the infections - malaria, UTI, HIV infection and intestinal helminths were observed to be not significantly associated with anaemia in pregnancy. There was no significant association between anaemia and level of education or socio-economic class. However, anaemia was found to be significantly associated with parity, birth interval, trimester of pregnancy at booking and iron deficiency. The strongest determinant of anaemia in pregnancy in the study subjects was iron deficiency.

Educating women on the benefits of early commencement of antenatal care will help reduce the prevalence and severity of anaemia in pregnancy. Education should include family planning, dietary advice, prevention of infections and improved personal and environmental hygiene.

TABLE OF CONTENTS

CONTENTS                                                                                                                                      PAGES

Declaration ............................................................................................................................. i

Acknowledgement  .................................................................................................................. ii

Dedication ............................................................................................................................... iii

Certification ............................................................................................................................. iv

Table of contents ...................................................................................................................... v

List of tables ............................................................................................................................ ix

List of figures .......................................................................................................................... xi

Abstract .................................................................................................................................... 1

CHAPTER ONE: Introduction ............................................................................................... 3

1.1 Introduction ........................................................................................................................3

1.2 Statement of the problem ..................................................................................................16

1.3 Aim and objectives ............................................................................................................17

1.4 Relevance of study ........................................................................................................... 17

CHAPTER TWO: Literature review ...................................................................................... 19

2.1 Erythropoiesis ....................................................................................................................19

2.2 Anaemia ........................................................................................................................... 21

2.2.1 Definition ................................................................................................................ 21

2.2.2 Classification of anaemia ................................................................................... .... 21

2.3 Determinants of anaemia in pregnancy ............................................................................23

2.3.1 Biological risk factors ............................................................................................. 23

2.3.2 Behavioural determinants ....................................................................................... 53

2.3.3 Socio – cultural and environmental factors ............................................................ 54

2.4 Effects of anaemia in pregnancy ..................................................................................... 55

2.5 Diagnosis of anaemia ....................................................................................................... 57

2.6 Prevention of anaemia .......................................................................................................58

2.7 Treatment ..........................................................................................................................60

CHAPTER THREE: Materials and methods ........................................................................ 62

3.1 Study environment ........................................................................................................... 62

3.2 Study population .............................................................................................................. 63

3.3 Sample size ....................................................................................................................... 63

3.4 Sampling method .............................................................................................................. 64

3.5 Selection criteria ................................................................................................................64

3.6 Data collection .................................................................................................................. 65

3.7 Data analysis .................................................................................................................... 73

CHAPTER FOUR: Results .................................................................................................... 74

4.1 Socio-demographic characteristics ....................................................................................74

4.2 History of current pregnancy ............................................................................................76

4.2.1 Parity ........................................................................................................................76

4.2.2 Birth interval ............................................................................................................76

4.2.3 Gestational age (trimester) at ANC booking ...........................................................77

4.2.4 History of antepartum haemorrhage .........................................................................78

4.3 Past medical history ..........................................................................................................78

4.4 Physical examination .........................................................................................................78

4.5 Laboratory results ..............................................................................................................79

4.5.1 Haematologic indices ..............................................................................................79

4.5.2 Infections .................................................................................................................81

4.6 Determinants of anaemia in pregnancy .............................................................................83

4.6.1 Level of education ..................................................................................................83

4.6.2 Socio-economic class ..............................................................................................84

4.6.3 Parity .......................................................................................................................84

4.6.4 Birth interval ...........................................................................................................87

4.6.5 Trimester of pregnancy at booking ..........................................................................88

4.6.6 Infections .................................................................................................................89

4.6.7 Iron deficiency .........................................................................................................91

CHAPTER FIVE: Discussion ............................................................................................... 92

5.1 Discussion ...................................................................................................................... 92

5.2 Conclusion ..................................................................................................................... 100

5.3 Recommendations ...........................................................................................................102

REFERENCES .................................................................................................................... 104

APPENDIX A: Consent form ............................................................................................. 122

APPENDIX B: Questionnaire ............................................................................................. 123

APPENDIX C: Ethical clearance ........................................................................................ 126

                                                       CHAPTER ONE

                                                               INTRODUCTION

1.1 INTRODUCTION

Anaemia in pregnancy is defined by the World Health Organisation (WHO) as haemoglobin concentration (Hb) below 11g/dl.1,2 Anaemia can be classified as mild, moderate or severe anaemia.2 The WHO pegs the Hb levels for each of these classes of anaemia in pregnancy at 10.0-10.9g/dl (mild anaemia), 7.0-9.9g/dl (moderate anaemia) and less than 7.0g/dl (severe anaemia).2

Anaemia is an important public health problem worldwide with the most vulnerable groups being women and children.3,4 The World Health Organisation estimates that more than half of the pregnant women in the world have haemoglobin concentration indicative of anaemia.1,2 The burden, unfortunately, is carried by the developing countries where anaemia is thought to be one of the most common problems affecting pregnant women in these countries.1,2,4 In developed countries, it is estimated that 15% of the pregnant women are anaemic and in developing countries, 33-75% of pregnant women have haemoglobin concentration indicative of anaemia.1 This clearly reflects the disparity in the prevalence of anaemia between the developed and less developed countries and also within the developing countries as evidenced by the wide range in the prevalence of anaemia in this region. This disparity occurs because of differences in, and severity of, the various determinants of anaemia in various areas.5 Evaluating the prevalence of anaemia in pregnancy in various parts of Nigeria, Tukur et al in Jos reported a prevalence of 20.9%, Cyril et al in Enugu reported a prevalence of 40.4%, Lamina et al in Sagamu reported 55.3% and Idowu et al in Abeokuta reported a prevalence of 76.5%. Though unlike the others who defined anaemia as Hb < 11g/dl, Tukur et al defined anaemia as Hb < 10g/dl.1,2,6,7 In Sekyere West district of Ghana, Glover-Amenger et al reported a prevalence of 57.1%; even though the definition of anaemia used in the study was haemoglobin concentration of less than 10g/dl and not the World Health Organisation definition of less than 11g/dl.3 In the Chiradzulu district, a rural area in Malawi, the prevalence of anaemia was reported to be 72%.4 As reported by Cot et al, the prevalence of anaemia in pregnancy in the Democratic republic of Congo is 72% and in Papau-New Guinea, it is 94%.8 Hogue et al reported a prevalence of 39.9% in Grey-town South Africa and Muhangi et al reported 39.7% in Entebbe, Uganda.9,10 Guatam et al reported a prevalence of 96.5% in a study

conducted in two villages in Delhi, India.11

Anaemia in pregnancy is known to contribute significantly to maternal morbidity and mortality and also affect fetal well being and perinatal morbidity and mortality.1,2,12,13 In malaria endemic areas like Nigeria, it is a major cause of morbidity and mortality.2 In Africa, it is estimated that 20% of maternal deaths are attributable to maternal anaemia as when anaemia is not the primary cause of mortality, it is a contributory factor especially following haemorrhage.2,14 In a comprehensive review of all published studies from malaria endemic areas between 1985 and 2000, Steketee et al estimated that maternal anaemia contributed to 7-18% of low birth weight and to 25% of total infant mortality.15 Various studies conducted both in developed and malaria endemic countries have observed that only severe maternal anaemia could be associated with these complications. Thus, they can be prevented if severe anaemia is prevented by prompt correction of mild-moderate anaemia when detected early in pregnancy.8 However, the most ideal situation would be prevention of any form of anaemia in women of child-bearing age.

It has been estimated that nearly 600,000 women die each year as a result of complications of pregnancy and childbirth.16 Most of these deaths occur in the developing countries where the risk of women dying in pregnancy and childbirth is 50-100 times greater than of women in the developed world.16 The maternal mortality in the developing countries worldwide is estimated at 400/100,000 but this is less than the mortality rate in some regions: Korle-Bu in Ghana has a maternal mortality rate of 734.4/100,000 and in some parts of Northern Nigeria, it exceeds 1000/100,000.14 The Netherlands has a maternal mortality rate of 5/100,000 and this, when compared to the rates in the developing countries, makes a clear impression of the problem yet to be addressed in the developing countries.14

In a study reviewing the determinants of anaemia in Malawi, these were classified as biological risk factors, behavioural determinants, socio-cultural and environmental determinants.4 Biological risk factors include the physiological haematologic changes in pregnancy, maternal age, gravidity, nutritional deficiencies and infections.4 Behavioural determinants include health seeking behaviours and dietary restrictions.4 Socio-cultural determinants include literacy level, socio-economic status, the perception of the society of the problem of anaemia during pregnancy by the society and cultural food taboos.4 This study, however, did not consider the history of recurrent antepartum haemorrhage which is a cause of anaemia in pregnancy.14 Pica has been identified as a risk factor for anaemia.1 Cyril et al considered that pica could be applicable in South-Eastern Nigeria where a special type of clay of the kaolinite group ( called `nzu’ in Igbo language) is easily accessible in the open markets and some pregnant women crave it.1

During normal pregnancy, various haematologic changes that eventually affect the haemoglobin concentration of the woman occur. There is a 50% increase in plasma volume through pregnancy and a corresponding increase in red cell volume of only 20-30% of prepregnancy level.14 This disparity in the increase of plasma volume and red cell volume results in a dilutional anaemia.14 Clinically, this haemodilution is seen as a fall in haemoglobin concentration commonly in the second trimester.17

Although some studies have found that anaemia is more common among adolescents, this observation appears to be a result of the fact that adolescents are more often primigravidae and not from the young age of the women per se.4 In a study carried out in two hospitals in Malawi, univariate analysis showed an increased risk of anaemia for women under 20 years of age but when data was corrected for gravidity and gestational age at booking, the increased risk with age no longer existed.4 Glover-Amenger et al in Ghana however reported that young age was significantly associated with low haemoglobin concentration and the highest prevalence of maternal anaemia.3

Gravidity is the most important determinant of maternal response to pregnancy even though the biological mechanisms through which gravidity is associated with anaemia is unclear.4,12 A study carried out in Blantrye and Namitambo in Malawi showed that, adjusted for age and gestational age, primipara were at an increased risk of anaemia and severe anaemia when compared to grand multipara in both rural and urban settings.4 In Ghana, low parity was reported to be significantly associated with low haemoglobin concentration and a high prevalence of maternal anaemia.3 Idowu et al reported that in Abeokuta 62.5% of the pregnant women were already anaemic at the time of antenatal booking and the prevalence was significantly higher among the primigravidae (69.7%).2

In sub-Saharan Africa, anaemia in pregnancy is most often believed to be due to nutritional deficiencies especially iron deficiency; this is despite the lack of stringent criteria, problems with definitions and the lack of substantial supportive data.4,12 Folate deficiency has been described in West Africa and studies from Indonesia have indicated that vitamin A deficiency may contribute to anaemia in pregnancy.12,13 Following various studies in Zimbabwe, it was concluded that the previously unrecognised role of vitamin B12 deficiency in anaemia was actually important.12 It is imperative to note that micronutrient deficiencies, which are often studied in isolation, actually are very likely to occur together so that people tend to have multiple micronutrient deficiencies at the same time.17  It is estimated that iron deficiency anaemia affects as many as 200 million people in the world so probably making it the commonest nutritional deficiency in the world.4 At least half of the cases of anaemia in pregnant women can be attributed to iron deficiency.4 Singh et al following a cross-sectional study in Singapore found iron deficiency to be the most common cause of anaemia in pregnancy with a prevalence of 81.3%.18 A study in Shire Valley in Malawi, in which women were screened at their first antenatal visit over a period of 16 months, reported that iron deficiency was independently associated with anaemia in primigravidae.4 Among Nepali pregnant women, the prevalence of low serum ferritin was high especially among the severely anaemic women (55.6%).19

The association between iron deficiency and anaemia in pregnancy has been reported to be significant by Hinderaker et al in rural Tanzania and Suega et al in Bali, Indonesia.20,21 Iron deficiency understandably precedes anaemia and thus the prevalence of iron deficiency is greater than that of anaemia.4,13 It has been reported that the prevalence of iron deficiency may be two to three times that of anaemia, ranging from about 50% in some countries to nearly 100% in parts of others.4

Iron deficiency is often nutritional in origin.4 Iron is obtained in the form of non-haem iron derived from vegetables and as haem iron derived from meat.14 Haem iron is absorbed two to three times better than non-haem and a small amount of haem iron in food improves the absorption of non-haem iron.4,14 In less developed countries, a major contributory factor in the prevalence of iron deficiency is the consumption of plant based foods containing insufficient available haem iron from meat.4

Infections also contribute to iron deficiency in developing countries where these infections are prevalent.4 Infections causing chronic blood loss such as hookworm infection and schistosomiasis increase the iron requirement of the patient.4 Viral and bacterial infections may also interfere with food intake, absorption, storage and use of many nutrients including iron.4 Repeated episodes of infections thus may contribute to the development of iron deficiency and anaemia.4

The gold standard for identifying iron deficiency anaemia has been the examination of suitably stained bone marrow aspirates for population screening.4 Serum ferritin has been shown to be a good measurement of storage iron. In a study in south Malawi, all the commonly available variables for measuring iron status were evaluated and serum ferritin was considered the best predictor of iron deficiency especially when a single serum variable was to be used.12 Serum ferritin is also an acute phase protein and so the serum concentration of ferritin increases in both acute and chronic infections. Because of this, a higher cut-off point for the definition of iron deficiency has been found to be more accurate (higher sensitivity and a higher specificity).4 In regions where infections are very common, like the developing countries, iron deficiency is defined as serum ferritin of less than 30µg/L instead of 12µg/L used in areas where infection is not considered an issue.4 On blood film, iron deficiency manifests as microcytosis and hypochromasia. These changes in the red blood cell result in reduction in mean corpuscular volume (MCV) and mean cell haemoglobin (MCH); both parameters are of very low accuracy and are far preceded by iron deficiency.4

Studies have shown that there is a steady fall in the concentration of serum folate throughout pregnancy especially in women from poor socio-economic groups, multigravidae, in smokers and in women with twin pregnancies.4 Folate deficiency has been reported to be common in West Africa and is largely attributable to nutritional inadequacy, malaria, haemoglobinopathies and a high frequency of twinning.14Since 1968, a study done in Ibadan, Nigeria found 75% of severely anaemic pregnant women had folate deficiency.10 More recently, Hinderaker et al in Tanzania and van den Broek in Malawi also reported a significant association between folate deficiency and anaemia in pregnancy.12,20

Folates are present in all foods but are more plentiful in the liver and in dark vegetable leaves and a diet rich in vitamin B and/or vitamin C is usually rich in folate also.4 Unfortunately some of the important staples in the developing countries such as rice, millet, sorghum, cassava and maize are poor sources of folate.4 Folates are heat labile and water soluble and so are destroyed by excessive heat as in cooking.4 In Nigeria foods are often well cooked so the chance of destroying the little folate present in the predominantly starchy foods is increased. Folate requirement approximately doubles during pregnancy and since the body storage of folates is limited and dietary folate is likely to be insufficient

in developing countries, anaemia may develop as a consequence.4,14

Muscle, red blood cell and serum vitamin B12 concentrations fall during pregnancy and this fall is progressive throughout pregnancy.4 The recommended intake of vitamin B12 is 2.0µg per day in the non-pregnant and 3.0µg per day in the pregnant women and these can be met by any diet which contains animal products.4 In Malawi, van den Broek et al found that one-third of the anaemic pregnant women were vitamin B12 deficient.12 In that study, 21% of the women with vitamin B12 deficiency were also folate deficient.12

Vitamin A has been known to play an important role in haematopoiesis and during pregnancy, serum retinol concentration has been shown to drop below non-pregnant concentration.4,12 In a study by van den Broek et al, where retinol deficiency was defined as serum retinol concentration of 0.7µmol/L or less, 39% of the anaemic women were deficient of retinol.12 In that study, vitamin A was the only micronutrient deficient in 15% of the anaemic women making it the second most frequent single micronutrient deficiency after iron deficiency in the study group.12 Vitamin A has been documented to improve the utilization of iron in the body as vitamin A supplementation has been shown, particularly in women with low serum retinol concentration, to improve mobilisation of iron stores.4 Parasitic infections known to cause anaemia include malaria, hookworm infection and schistosomiasis.3,12 Malaria is the most important of the parasitic diseases of human beings especially for the people living in sub-Saharan Africa where about 90% of all the deaths due to malaria occur.22

Malaria is caused by the Plasmodium species (P. malariae, ovale, vivax and falciparum). The impact of malaria during pregnancy was described nearly a century ago due to observations which were undertaken during epidemics in areas of low transmission of malaria.8 Malaria is an important cause of maternal anaemia.12,14 This is particularly important in sub-Saharan Africa where it is estimated that 23 million pregnant women are exposed to malaria and the impact of the infection yearly, but less than 5% of this population have access to effective interventions.12,23,24 Unlike in areas of low endemicity where pregnant women develop acute symptoms like fever with malaria infection, in areas of high endemicity (like sub-Saharan Africa) malaria often is asymptomatic so remaining undetected and untreated.24,25 In areas of low endemicity, more severe complications of malaria such as cerebral malaria and pulmonary oedema are seen but in areas of high endemicity, the most common complications of malaria in pregnancy are maternal anaemia and low birth weight.3,8 Low birth weight associated with malaria in pregnancy is estimated

to result in 100,000 infant deaths in Africa each year.24

The susceptibility of pregnant women to malaria has been reported by various studies. One of the reasons given for this is the ability of the malaria parasite to sequester in the placenta so avoiding splenic clearance.3 In areas of low endemicity both primigravidae and multigravidae are affected by malaria with the same intensity. However, in areas of high endemicity, women in their first and second pregnancies are at a higher risk of acquiring malaria than non-pregnant women or multigravidae.4 This is due to the reduction of both cellular and humoural immune response to the malaria parasite that had been acquired through life.4 In areas of high endemicity, parasitaemia is more frequent and the parasite density is higher during the first and, to a lesser extent, the second pregnancy than in multigravidae or in the non-pregnant women.8 Akanbi et al reported that in Ibadan, Nigeria, the prevalence of malaria among the pregnant women was higher than that in the nonpregnant control group (23.08% versus 7.1%).26 In the same study, it was observed that the mean parasite density in pregnant women was significantly higher among the primigravidae than in the multigravidae (3144 ± 107 versus 1014 ± 158) and the mean parasite density was significantly higher in both the primigravidae and multigravidae than in the nonpregnant control group(101 ± 70).26

The association between malaria in pregnancy and maternal anaemia has been reported by several studies. Troye-Blomberg et al in Cameroon reported that the prevalence of anaemia at first booking clinic was 68.9% and in the group of anaemic women, the mean haemoglobin concentration of malaria positive women was significantly lower than that of the malaria negative women.27 Muhangi et al in Uganda, Hinderaker et al in rural Northern Tanzania and Marchant et al in South Tanzania all reported a strong association between malaria parasitaemia and maternal anaemia.10,20,28

For pregnant women in the sub-Saharan Africa, the impact of malaria in pregnancy is exacerbated by factors that are prevalent in the region. These include poor nutrition, micronutrient imbalance (particularly vitamin A, zinc, iron and folate), HIV infection, poverty and limited access to effective health care and emergency obstetric services.23 The impact of malaria in pregnancy is also made obvious by the conclusion reached after a meta-analysis of intervention trials that successful prevention of these infections reduces the risk of severe maternal anaemia by 33%, low birth weight by 43% and perinatal mortality by 27% among paucigravidae.24

Hookworm infestation is described to be one of the principal causes of iron deficiency anaemia in developing countries.3,4 It is prevalent throughout the tropics and sub-tropicswherever there is faecal contamination of the environment and is acquired mainly by contact with contaminated soil, water or vegetation.4 The prevalence of hookworm infestation among pregnant women in sub-Saharan Africa has been estimated to be 32% and along with ascariasis, has been associated with iron deficiency anaemia in Nigeria.29 Egwunyenga et al, in a study based in three centres in Nigeria (Jos, Bauchi, Eku), reported that hookworm and Ascaris lumbricoides infections were the predominant helminth infections accounting for 69% of all helminthic infections.29 Glover-Amenger et al in Ghana reported an association between the presence of hookworm eggs in stool and maternal anaemia. In the same study it was observed that independent of malaria parasitaemia, hookworm was even more strongly associated with low haemoglobin concentration than malaria in pregnancy.3 In Entebbe, Uganda, the prevalence of various intestinal parasites among pregnant women were reported as hookworm 45%, Mansonella perstans 21.3%, S. mansoni 18.3%, Strongyloides 12.3%, Trichuris 9.1%, Ascaris 2.3% but only a weak association was found between anaemia and increasing intensity of hookworm infection.10 In Indonesia, Nurdia et al reported that 69.7% of the pregnant women were infected with at least one species of pathogenic intestinal helminths with the most common ones being Trichuris trichura and the hookworms.21 The study reported a significant negative association between hookworm infection and serum ferritin.21

Egwunyenga et al studied Plasmodium/intestinal helminth co-infections among pregnant women and reported that pregnant women with Plasmodium/intestinal helminth coinfections, especially among the primigravidae, had a lower haemoglobin concentration than those who suffered only from malaria infection.29

Schistosomiasis is an infection caused by the Schistosoma species. The species commonly found in Africa are S. mansoni and S. haematobium which cause chronic blood loss from the large bowel and the bladder respectively. This blood loss can contribute significantly to development of anaemia. In North-west Tanzania, it was found that 3.5% of the pregnant women were infected with S. mansoni and 56% with hookworm.30 The prevalence of anaemia in this study was 66.4% but increased risk of anaemia was associated with only S. mansoni infection.30 The prevalence of S. mansoni in pregnant women in Uganda was reported to be 18.3% but the association between this and anaemia was weak.10 Trichuris trichura in pregnant women was reported in studies by Nurdia et al in Indonesia, Egwunyenga et al in Nigeria and Muhangi et al in Uganda.10,21,29It was the most common helminth detected in the Indonesia study.21

Antenatal antihelminthic treatment in hookworm endemic areas has been recommended for the control of anaemia.31 The recommendation for this emerged from a study in Sri-Lanka where antenatal mebendazole lowered the frequency of anaemia and safely reduced the proportions of infants of very low birth weight.32 This recommendation has been reemphasized by various studies but despite the substantial role of this treatment, particularly

to severe anaemia, it is uncommon in many developing countries.21,29,32 

Infection with the Human immunodeficiency virus (HIV) has emerged as an additional important risk factor for anaemia in pregnancy and it must be included as a differential diagnosis.3,4 Anaemia in people infected with HIV may occur due to the virus itself, predisposition to opportunistic infections or malignancies that cause anaemia or due to medications. HIV infection has also been associated with a lower serum folate and serum ferritin in pregnancy and it also increases the risk of malaria and its adverse effects-these all contribute to anaemia.1,24 When anaemia is associated with leucopenia and thrombocytopaenia, the clinician should be alerted to the possibility of Acquired immunodeficiency syndrome (AIDS). In a study by van den Broek et al in Malawi, the observed prevalence of HIV seropositivity in the group of anaemic women was 47.1% and this was significantly higher than the prevalence in the whole antenatal population (30.1%).4 In this study, the mean haemoglobin concentration for the HIV seropositive group was 8.1g/dl which was significantly lower than the 8.8g/dl of the seronegative group.4 The mean C-reactive protein (CRP) concentration, a marker of inflammation,  was significantly higher in the HIV seropositive group compared to the seronegative group

(167nmol/L versus 29nmol/L) and this has been associated with anaemia in pregnancy.4 The association between HIV infection and anaemia in pregnancy has also been shown to be strong in studies by Cyril et al in Nigeria and Muhangi et al in Uganda.1,10 HIV infection increases the risk of malaria infection, its intensity and adverse effects.8,24 The first observations in Malawi, where nearly 3000 pregnant women were followed between 1987 and 1989, showed an increase in the parasite prevalence and density in HIV seropositive women compared to the seronegative women.8 These findings were more recently confirmed by two studies in Malawi and Kenya.8 Several studies have noted that the usual pattern of increased parasite density and prevalence in primigravidae is altered so that HIV seropositive multigravidae are at similar risk of malaria and its adverse effects (like anaemia) as HIV seropositive primigravidae.8,24

Chronic inflammation has been associated with anaemia in pregnancy by various studies. Common markers of inflammation are the erythrocyte sedimentation rate (ESR) and the Creactive protein (CRP). The concentrations of these markers, however, are also known to be raised as a physiologic response to pregnancy but the cut-offs for CRP are well established for pregnancy and values of greater than 190nmol/L are considered elevated.12 In a study in Malawi, 19% of the anaemic women had no demonstrable deficiencies of iron, vitamin B12, folate or vitamin A nor an identifiable parasitic infection at the time of the study.12 Among this group, more than half (54%) had CRP concentrations suggestive of chronic inflammation.12 Of the anaemic but iron-replete women in a study, 73% of the women had elevated CRP concentrations thus suggesting that chronic inflammation was associated with ( and possibly responsible for) their anaemia.12 Bondevik et al in Nepal and Hinderaker et al in Tanzania have re-emphasised the significant association between anaemia in pregnancy and elevated CRP concentration.19,20 Some suggested possibilities of the sources of infection are urinary tract infection (UTI), sexually transmitted infections (STI) and tuberculosis.12 The association between HIV infection and CRP concentration has been discussed earlier. The Bondevik study concluded that along with dietary advice, prevention, detection and treatment of infections should be more strongly emphasised as part of the antenatal care aimed at reducing the prevalence of anaemia in pregnancy.19  Urinary tract infections are the most common bacterial infections that complicate pregnancy.33 UTI may present as symptomatic or asymptomatic bacteriuria.33 Anaemia, along with preterm labour/delivery and low birth weight, are recognised adverse effects of asymptomatic bacteriuria.20,33,34 Asymptomatic bacteriuria refers to the infection of the urinary tract without symptoms and a positive urine culture is diagnostic of this.33,34 A positive culture is defined as more than 100,000 bacterial colonies of two or more urogenic bacteria per millilitre of urine after 48 hours of culture.35 Pregnant women have an increased risk of UTI. Asymptomatic bacteriuria, which may precede symptomatic UTI, is common with a prevalence of 10% during pregnancy with 13-27% of untreated women developing pyelonephritis during the pregnancy.34

UTI has been shown to be more prevalent among women of the lower socio-economic status and in those with a pre-pregnancy history of UTI.35 Across Nigeria, the prevalence of asymptomatic bacteriuria has been reported to be 21% by Akinloye et al in Ibadan, 12.7% in Enugu by Onyemelukwe et al, and 86.6% in Benin City by Akerele et al.34,36,37 Turpin et al in Ghana reported that the prevalence or asymptomatic bacteriuria in the study population of pregnant women was 7.3%.38 The prevalence of asymptomatic bacteriuria in the developing countries is three times higher than in the developed countries.34 The prevalence of asymptomatic bacteriuria in Canada has been reported to be 4-7%.38  The prevalence of anaemia in pregnancy, though varying widely, is unacceptably high in the developing countries; Nigeria inclusive. The possible aetiological factors are multiple and their relative distributions can be expected to vary in different populations. The knowledge of the significance of the various possible determinants in a specific population can be used as the basis for intervention strategies.

1.2 STATEMENT OF THE PROBLEM

A fall in haemoglobin concentration or packed cell volume occurs in normal pregnancy due to physiologic haemodilution. This may result in anaemia in any pregnant woman worldwide.

The prevalence of anaemia in pregnancy is documented to be higher in developing countries compared to the developed countries. In the developing countries, the prevalence varies widely from place to place. This may imply localised determinants and/or severity of association between the determinants and the prevalence of anaemia in pregnancy. In Plateau State Specialist Hospital, the researcher observed that anaemia in pregnancy at booking was not uncommon. It was also seen amongst women who booked in the first trimester; so reducing the chance that it was physiological. Anaemia was also noticed to be common among women who came from peripheral health facilities referred due to various problems or to deliver.

This study is intended to provide knowledge of the severity of the problem in Jos. It will also provide information on the possible determinants and their strength of association with anaemia in pregnancy. The study will enable the researcher to make recommendations on a multifaceted approach to this problem.

1.3 AIM AND OBJECTIVES

AIM

To contribute to the reduction of anaemia in pregnancy by determining its prevalence and identifying the determinants in a population of antenatal women in Jos.

OBJECTIVES

  1. To determine the prevalence of anaemia in pregnancy in the study population.
  2. To identify the determinants associated with anaemia in pregnancy in the study population.

1.4 RELEVANCE OF STUDY

The aetiology of anaemia in pregnancy is multi-factorial, extending out of the clinical setting into behaviours, family and environment. The knowledge of the burden of this problem and the associated determinants in the study population will identify areas for possible interventions. These may include health education to the women, their families and the community, health service planning for intervention and treatment and also points for advocacy. This will enhance specific targeted interventions and holistic management of the problem-even before and between pregnancies. All these are aimed at reducing the burden of anaemia in pregnancy which affects not only the women but the unborn child and the family.

PREVALENCE AND DETERMINANTS OF ANAEMIA IN PREGNANT WOMEN ATTENDING ANTENATAL CLINIC IN JOS, PLATEAU STATE, NIGERIA.

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