Anaemia, Morphological Classification and Its Associated Risk Factors Among Lactating Mothers at Mbarara City Council Health Centre IV, Southwestern Uganda

Introduction

Anaemia is a condition in which blood hemoglobin concentration is below normal for age and sex with inadequate oxygen carrying capacity of red blood cells for normal physiological processes.¹ World Health Organization (WHO) defines anaemia in non-pregnant women as blood hemoglobin concentration <120 g/L and severe anaemia as blood hemoglobin concentration <70g/L.²

Anaemia is a global public health burden affecting about 1.74 billion people,³ with 29.6% of non-pregnant women anaemic worldwide.⁴ Anaemia has impacts on health as well as social and economic development of both rich and poor countries. Regional prevalence of anaemia among non-pregnant women ranges from 16% in high income countries to 48% in central and western Africa.⁵

Several studies have reported prevalence of anaemia among lactating mothers as: 32.7% in China,⁶ 60.3% in Myanmar in 2014⁷ and 73.8% in 2016,⁸ 62.9% in India⁹ and 8–24% in Denmark.¹⁰

Lactating mothers are vulnerable to anaemia because of iron depletion during lactation and blood loss during delivery.^8,11 Breast milk iron concentration has been known to be maintained at the expense of the mother’s iron stores and mothers who had anaemia during pregnancy have higher chances to develop anaemia during lactation.¹ East African region has reported 22%¹² and 25%¹³ prevalence of anaemia among postnatal mothers in Tanzania and Kenya, respectively, and the Horn of Africa is equally affected by anaemia in lactating mothers. Studies have estimated prevalence of anaemia among lactating mothers in Ethiopia to have increased from 21.8%¹⁴ and 22.1%¹¹ to 28.3%.¹⁵

Several factors have been found to predict anaemia in lactating mothers in low income countries and these include: iron deficiency, vitamin A, C, B₁₂ and folate deficiency, parasitic infection, multi-gravidity, antepartum anaemia, low income level, young lactating age and infectious diseases.^1,6,7

In Uganda the prevalence of anaemia among breastfeeding mothers is 34%.¹⁶ The regional variation of anaemia among non-pregnant women ranges from 16.9% in Kigezi to 47.1% in Acholi.¹⁷ There is scarcity of data on the prevalence of anaemia among lactating mothers in Mbarara district and in Uganda in general. The aim of this study was therefore to determine the prevalence of anaemia and its associated risk factors among lactating mothers at Mbarara City Health Centre IV (MC HC IV), Southwestern Uganda.

Materials and Methods

Study Design and Site

This was a cross-sectional study carried out at Mbarara City Health Centre IV (MC-HC IV) from October to December 2021, located in Mbarara City in Southwestern Uganda. MCHC-IV is a public health facility that serves the population of Mbarara city, including referrals from other low level health centres within the city. It offers services like: immunization, family planning, ante/postnatal care, prevention of mother-to-child transmission (PMTCT), HIV/AIDS clinic, general outpatient (OPD), minor surgeries for male circumcision and laboratory services.

Sample Size Calculation

The sample size for this study was estimated using the formula for a single population proportion, with the following assumptions: anaemia prevalence of 22% in lactating mothers,¹² at 95% confidence level, and 5% marginal error. Using the formula for sample size calculation for the proportion.

n= Z²P(1-P)/d²

Where: n=the desired sample size

Z=critical values of normal distribution at 95%, which corresponds to 1.96

P=the proportion of the target population estimated to have anaemia

d=estimated margin of error 5%

n=264

Sample size was then adjusted for 10% non-response rate and the minimum sample size calculated was 290 lactating mothers. There was however low turn up to postnatal clinic so this was not attained but considering the fact that ratio of each variables under study to sample size was between 5 to 10, this sample size was adequate for multivariate level of analysis.

Sampling Procedure

Two hundred and sixty four (n=264) lactating mothers were randomly selected and subjected to structured questionnaires to obtain information on sociodemographic characteristics, dietary intake, mid upper arm circumference (MUAC), iron supplementation, number of antenatal and postnatal visits, use of treated mosquito nets, tea consumption, alcohol intake, deworming status, source of drinking water, and history of post-partum hemorrhage.

Laboratory Procedure

About 4mL of venous blood was collected aseptically into an EDTA vacutainer. Complete blood count was performed using (BC 2800 Mindray Hematology Analyzer), peripheral thin blood smears were made, fixed with absolute methanol and stained using 10% Giemsa–Maygrunwald stain for the morphological classification of anaemia.

Ethical Consideration

This study was approved by the Faculty Research Committee (FRC) of Mbarara University of Science and Technology and Mbarara City health officer (approval number MUST/MLS/023). Written Informed consent was obtained from the study participants and the study protocol conformed to the ethical guidelines of the 1975 Declaration of Helsinki (1964). Privacy and confidentiality was followed all through the study process and those with anaemia were referred to physicians for management.

Results

Demographic Characteristics of the Study Participants

The mean age was 26 years, 95% CI (25.4–26.7). The participants’ ages ranged from 18 years to 45 years. Majority of the lactating mothers were aged between 20 to 29 years, 192 (72.7%), and those within the first 4 months of lactation were 169 (64%), mothers who had attained secondary education 126 (47.7%), married 252 (95.4%), and employed 155 (58.7%). Those with 1–2 parities, 195 (73.9%), and those with ≥4 antenatal visits during pregnancy were 214 (81.1%), as shown in Table 1.

Table 1 Demographic Characteristics of Study Participants

Prevalence of Anaemia

The overall prevalence of anaemia among lactating mothers was 65 (24.6%), as shown in Figure 1. According to WHO’s definition of severity of anaemia, anaemia is classified as mild anaemia when the Hb is (10.0–11.9g/dL), moderate (7.0–9.9g/dL) and severe (<7.0g/dL). In this study, 2 (0.7%) had severe anaemia, 11 (4.2%) had moderate anaemia and 52 (19.7%) had mild anaemia.

Figure 1 Pie chart showing prevalence of anaemia among lactating mothers at Mbarara City Health Centre IV.

Morphological Classification of Anaemia

Based on the peripheral blood reports, majority 27 (41.5%), of the participants had normocytic normochromic anaemia, 20 (30.8%) had microcytic hypochromic, 16 (24.1%) had normocytic hypochromic and 2 (3.1%) had macrocytic normochromic anaemia, as shown in Figure 2.

Figure 2 Morphological classification of anaemia among lactating mothers at Mbarara City Health Centre IV. Abbreviations: MH, Microcytic hypochromic anaemia; NH, Normocytic hypochromic anaemia; NN, Normocytic normochromic anaemia; MN, Macrocytic normochromic anaemia.

Risks Factors Associated with Anaemia

Several factors considered to be associated with anaemia during lactation were studied. These included age, duration of lactation, education level, marital status, occupation of mother, occupation of spouse, number of parities, household income, use of mosquito bed net, history of postpartum haemorrhage, use of iron supplements, alcohol consumption, tea consumption, deworming status, source of drinking water, malnutrition (MUAC <23.5 cm), number of antenatal (ANC) visits and consumption of iron-rich food (meat, fish, green vegetables, fruits and eggs).

On bivariate logistic regression, the following variables were found to be associated with anaemia: age group (40–49 years) (OR: 68.25, p-value 0.037), duration of lactation of 5 to 8 months (OR: 0.31, p-value 0.014), alcohol consumption (OR: 5.0, p-value 0.016) and having been dewormed in the last 3 months (OR: 0.41 and p-value 0.045); see Table 2.

Table 2 Bivariate Analysis of Risk Factors Predisposing Lactating Mothers to Anaemia

The factors that were significantly associated with anaemia in the bivariate logistic regression analysis were then subjected to multivariate logistic regression. Duration of lactation of 5 to 8 months (OR: 0.32, p-value 0.017) and alcohol consumption (OR: 3.69, p-value 0.032) remained significantly associated with anaemia during lactation (Table 3).

Table 3 Multivariate Analysis of Risk Factors Predisposing Lactating Mothers to Anaemia

Discussion

Prevalence of Anaemia

Anaemia in lactating mothers remains a public health burden affecting both the mother and the newborn.¹⁸ We determined the prevalence and risk factors of anaemia among lactating mothers at Mbarara City Health Centre IV (MCHC-IV). The overall prevalence of anaemia among lactating mothers was 24.6%. This prevalence is lower than the national prevalence of anaemia among lactating mothers in Uganda, which is 34%.¹⁶ The difference in prevalence in these two studies could be attributed to study design since the study across Uganda was a demographic health survey and this study was only in one region. The sample size in this study was also smaller than the health survey conducted among a very large number of study participants and differences in the techniques used in anaemia diagnosis.

This finding is comparable with studies from Kenya 25%,¹³ Tanzania with 22%¹² and several studies in Ethiopia 22.1%,¹¹ 28.3%¹⁵ and 28.9%.¹⁹ Our study was also similar to studies in Argentina and Nepal, with 25.8%²⁰ and 20%,²¹ respectively.

The prevalence of anaemia in this study is however lower than the prevalence reported in East Africa 36.5%,¹⁸ Myanmar 73.8%,⁸ India 62.9%,⁹ Binjai in Indonesia 52%,²² Ethiopia,43%²³ and Somalia 48.7%.¹¹ The lower prevalence of anaemia could be attributed to geographical location, feeding habits, differences in sample size and socioeconomic status of these lactating mothers in these studies compared to ours.

Our study finding was however higher than the prevalence reported in Japan, 10.5%.²⁴ This higher prevalence in our study could be due to differences in socio-economic status of lactating women in Japan and Uganda. It can also be due to larger sample size, geographical location, retrospective cohort study design and larger time period employed in the Japanese study.

Morphological Classification of Anaemia

According to our study, most of the anaemic study participants had normocytic normochromic blood picture (41.5%), followed by microcytic hypochromic blood picture (30.8%), normocytic hypochromic blood picture (24.1%) and macrocytic normochromic blood picture (3.1%). This finding disagreed with a study that reported microcytic hypochromic anaemia as the most prevalent morphological type of anaemia among lactating mothers in Ethiopia.²³ Normocytic normochromic anaemia was the commonest type of anaemia in our study because lactating mothers lose blood during delivery and also are at risk of being malnourished during lactation. This blood picture could also be attributed to early stage of iron deficiency, in which majority of the red blood cells are normocytic normochromic. However, normocytic normochromic anaemia is also found in other conditions like chronic infection, inflammatory diseases, malignant diseases, renal failure, hypothyroidism, hypopituitarism, marrow failure, acute blood loss and rheumatoid arthritis.²⁵ These conditions can also happen in the lactating phase, which could have contributed to normocytic normochromic anaemia to being the major morphological type of anaemia in this study. Generally, there is a scarcity of literatures on morphological classification of anaemia in lactating mothers; most studies that studied anaemia in lactating mothers used Hb, serum iron levels and ferritin in determining anaemia.

Associated Risk Factors with Anaemia

Alcohol affects the production of red bloods cells from bone marrow and promotes the production of abnormally shaped red blood cells that are destroyed earlier than their 120-day life cycle and this causes anaemia since destruction of abnormally shaped red blood cells reduces haemoglobin levels and reduces the oxygen carrying capacity of red blood cells that the body requires for normal physiology.²⁶ Alcohol consumption was found to be significantly associated with high odds of developing anaemia during lactation. This disagreed with a study done in agro-ecological zones of Ethiopia that studied drinking of Tella (local alcohol) and anaemia during lactation in rural Ethiopia and found no association.¹⁴

Lower duration of lactation that is 5 to 8 months were found to be significantly associated with lower odds of developing anaemia during lactation. This disagrees with a study that was done by Liyew et al in Ethiopia that showed that neither low nor high duration of breastfeeding was associated with anaemia during lactation.¹⁵ This could be due to health habit that since mothers lose blood during delivery, they are put on iron supplementation to restore their haemoglobin levels when they give birth at MCC-HC IV, so this lowers their odds of developing anaemia.

Conclusion

The reported prevalence of anaemia among lactating mothers in this study is a moderate public health problem. Duration of lactation (5 to 8 months) and alcohol consumption were risk factors found to be associated with anaemia. Routine anaemia screening of all postnatal mothers and iron supplementation immediately after delivery is recommended. Lactating mothers are also advised to reduce alcohol consumption during lactation period. Further studies are recommended to explore the underlying causes of anaemia during lactation.

Limitations of the Study

This study did not collect data on factors such as malaria, tuberculosis and HIV infection that can also predispose lactating mothers to anaemia.