Anaemia in pregnancy remains serious concern and burden in pregnant women and the number of women affected is still high. It contributes significantly to high maternal mortality and poor birth outcome worldwide [1, 2]. The level of haemoglobin vary by age, sex, altitude, smoking, and pregnancy status[1].
Anaemia is the commonest haematological disorder that may occur in pregnancy, the others being Rhesus iso-immunization and blood coagulation disorders[3–5]. Anaemia in pregnancy is an important public health problem worldwide, WHO estimates that more than half of pregnant women in the world have a haemoglobin level indicative of anaemia (< 11.0g/dl), the prevalence may however be as high as 56 or 61% in developing countries[3].
Anaemia in pregnancy is a common problem in most developing countries and major cause of morbidity and mortality especially in malaria endemic areas. It is frequently severe and contributes significantly to maternal mortality and reproductive health morbidity[6].
Anaemia in pregnancy it deserves more attention than it is currently receiving [7]. Published rates of prevalence of anaemia for developing countries range from 35–56% for Africa, 37–75% for Asia and 37–52% for Latin America, this is in sharp contrast to industrialized countries where anaemia in pregnancy occurs in less than 20% of women [8]. Exact population prevalence figures are usually not available for developing countries. Nevertheless it is clear to those in clinical practice and research that anaemia in pregnancy is a public health problem and under-reported[9]. Each year worldwide more than 500 000 women die from pregnancy related causes, the vast majority 99% in developing countries[9].
The incidence of anaemia in pregnancy ranges widely from 40–80% in tropics compared to 10–20% in the developed countries and is responsible for 20% of maternal deaths in the third world countries [10]. Women often become anaemic during pregnancy because the demand for iron and other vitamins is increased due to physiological burden of pregnancy [11]. The inability to meet the required level for these substances either as a result of dietary deficiencies or infection gives rise to anaemia [12, 13].
Globally, the most common cause of anaemia is iron deficiency, which is responsible for about half of anaemia cases in pregnancy, and it is estimated that in developed countries 38% of pregnant women have iron depletion[14].
Antenatal care is a key strategy to improve maternal and infant health[7]. However, survey data from sub-Saharan Africa indicate that women often only initiate ANC after the first trimester particularly adolescent pregnant women, therefore they do not fully benefit from its preventive and curative services[15]. In Tanzania, 97% of pregnant women attend antenatal care and 70% do so at least four times and do not achieve the recommended number of ANC visits[16].
Anaemia ranges from mild, moderate to severe and the WHO pegs the haemoglobin level for each of these types of anaemia in pregnancy at 10.0-10.9g/dl (mild anaemia), 7-9g/dl (moderate anaemia) and < 7g/dl (severe anaemia). But the pregnant woman in second trimester is said to be anaemic when haemoglobin level is less than 10.5g/dl [17]. Prevalence of anaemia can be as high as 42% in developing countries with a high incidence and severity occurring among primigravidae living in malaria endemic areas[18].
In Tanzania the most causes of anaemia in pregnant women are nutritional deficiencies, malaria, parasitic infestation, too short child spacing, poor diet (malnutrition), and chronic infection[12, 19]. Women often become anaemic during pregnancy because the demand for iron and other vitamins such as folic acid and vitamin B12 is increased due to physiological burden of pregnancy[2, 19].
Anaemia due to malaria in pregnancy is one of the major causes of maternal morbidity worldwide, and leads to poor birth outcomes [20, 21]. Maternal mortality in Tanzania from Demographic and health survey is estimated to be 556 deaths/100,000 live births[22].
In pregnancy, anaemia has a significant impact on the health of the foetus as well as that of the mother whereas 20% of maternal deaths in Africa have been attributed to anaemia[23]. Fetes is at risk of preterm deliveries, low birth weights, morbidity and perinatal mortality due to the impairment of oxygen delivery to placenta and foetus[24].
The disparity between high antenatal care attendance, high prevalence of anaemia in pregnancy, high maternal mortality raise questions about the quality of care provided and particularly the management of anaemia in pregnancy at antenatal clinics[21].
The management and control of anaemia in pregnancy is enhanced by the availability of local prevalence statistics, which is however not adequately provided in Tanzania. Therefore, this study aim to determine the prevalence and predictors of anaemia in pregnant woman attending antenatal clinics that can be used to reduce health problem pertaining to anaemia and changing the way used in treating and preventing anaemia.