Under-nutrition is a serious public health problem linked to a substantial increase in the risk of mortality and morbidity [1]. Malnutrition is one of the most devastating problems worldwide and is inextricably linked with poverty [2]. About 870 million people are estimated to have been undernourished which is 12.5% of the global population. The vast majority of these, 852 million, live in developing countries [3].

Malnutrition is a major public health concern in many developing countries particularly for women responsible for a significant proportion of morbidity and mortality in the affected countries [4]. The nutritional and health status of women is of great concern in the contemporary world, because the multiple roles played by women give rise to serious health and nutritional problems [5].

Women are generally vulnerable to under-nutrition especially during pregnancy and lactation where the food and nutrient requirements increased during that period [6]. Malnutrition passes from one generation to the next because malnourished mothers give birth to malnourished infant [7].

Low BMI, indicative of maternal under-nutrition, has declined somewhat in the past two decades but continues to be prevalent in Asia and Africa [8]. Lactating women from developing countries are considered nutritionally vulnerable groups because this period places a high nutritional demand on the mother especially for those mothers who often start their pregnancy in poor nutritional and health status [9, 10]. Poor maternal nutrition is directly associated with mothers lack of resistance to infection and to maternal ill health during child birth particularly among the poor. Ethiopia is one of the poor countries with the highest levels of lactating mother’s malnutrition in Sub-Saharan Africa [11, 12].

The Ethiopian demographic and health survey (EDHS) working paper, reported that the Ethiopian regions have a relatively higher prevalence of under-nutrition are found in the lowlands of the country, with the exception of the highlands of Tigiray, where under-nutrition is also prevalent [13]. However, there is lack of information in Tigiray as well as in Ethiopia to show under-nutrition in lactating women is prevalent in highland than lowland.

Therefore the current study is conducted to compare the prevalence and associated factors of under-nutrition among lactating women from lowland and highland communities. Finally planners, researchers, programmers as well as policy makers will use it as a source of information for their future nutrition intervention.

The majority of the participants from lowland and highland were food secured, but their frequency of meal intake was inadequate, or many of the participants were reporting not eating enough meals during the day, the probable reason for this finding may be the social desirability biased for the food security questionnaire. Women of reproductive age particularly lactating women were at a higher risk of insufficient micronutrient intake due to their low dietary diversity, as it was found from descriptive data of the current finding those lactating women from highland had low dietary diversity than lactating women from lowland, their low dietary diversity might be the cause for underweight of the participants since underweight was slightly higher in the highland than lowland, in general the dietary diversity of the majority of the participants from lowland and highland were low, this in turn affects their adequate micronutrient intake, thus the current finding was consistent with other study which noted that, micronutrient intakes for women of reproductive age are far from adequate [21]. The low dietary diversity intake of both comparison groups might be due to less frequency of meal per day, lack of taking extra meals during lactation period, dearth of knowledge regarding fruit and vegetable intake, and limited access to fresh-food markets and stores as well as per capita food consumption of participants, this was consistent with studies conducted to assess socioeconomic determinants of dietary patterns in low- and middle-income countries and a study conducted in Nepal [22, 23]. The mean WDDS of the current study both from lowland and highland were less than the mean WDDS of lactating women in a peri-urban area of Nepal and in rural Cambodia [24, 25], this might be due to the difference in the study population, and it might be also differences in socio-economic status.

Pulse plays a key role in providing nutrition to communities throughout the world. They are widely available, low in fat, and high in protein, minerals, and nutrients in the diet. In adequate intake of pulse indicates a deficit of protein rich. Protein deficiency is the causes of CED. Chronic intake of low amount of nutrient and energy may be the cause of underweight. In the current study the prevalence of underweight was high in the highland, even though cultivation of pulses in the highlands was higher, this may be the reason that the cultivated pulses may sold as income generating rather than household consumption.

Household food insecurity of the participants was measured and most of the participants from lowland and highland were most food secured. Slightly the food security status of the participants from highland was higher than their counterparts. But the prevalence of underweight was higher in the highland than in the lowland. The probable reason for this might be food security status in the highland does not mean that they are nutritionally secured.

The magnitude of chronic energy deficiency of lactating women in the lowlands of the current study was statically significantly lower than a study conducted in Ethiopia [14]. The probable reason for this might be difference in study population and study period. The magnitude of CED of lactating women in the highlands of the current study was found to be similar to the above study. The magnitude of CED of lactating women both in the lowland and highland communities were similar to studies conducted in Nekemte referral hospital and in Samre woreda, South Eastern Tigray, Ethiopia [12, 26]. The prevalence of CED in both comparison groups were lower than a study conducted in lactating women living in relief camps in Sri Lanka [27]. The reason behind may be difference in the living condition of the study population since the study population of the previous study were living in relief camps which make them vulnerable to under-nutrition.

Age of the participant was another factor associated with the nutritional status of lactating women. In the current study lowland inhabitant mothers who were aged from 25 to 35 were found to be 56.1% at reduced risk of CED when compared to those mothers aged <25 years. This finding is consistent with a study conducted in India [28]. Another study in Ethiopia, the highest proportion of malnourished women was observed in the youngest age group, followed by the oldest age group, the lowest rate was found in the age group 20–24 years [29]. The potential reasons for this might be in adolescence and young women nutritional needs increase because of their rapid growth that accompanies puberty and the increased demand for iron that is associated with the onset of menstruation.

Husband occupation was found to be one of associated factor in predicting women for the risk of CED. Those lactating women from lowland who have husband’s occupation working in private organization employee were 89.5% at reduced risk to be CED than those lowland lactating women who do have husband’s occupation working in farming. The probable reason for this could be those lactating women who have partners working in private organization employee may have higher income as compared to those lactating women who had partners working in farming. This finding was consistent with a study from India, partner’s occupation was also the major determinant factor for chronic energy deficiency [30]. Another study in Ethiopia, revealed that women who have agricultural worker partner’s were found to be highly vulnerable to the risk of chronic energy deficiency, low risk of chronic energy deficiency was observed on those who have professional partners [31].

Adequate micronutrient intake by women has important benefits for both women and their children. Maternal diet must provide sufficient energy and nutrients to meet the mother’s usual requirements, as well as the needs of the growing fetus [32]. In the current study taking of vitamin A immediately after delivery or within the first 8 weeks after delivery was found to be a significant factor in reducing chronic energy deficiency. Lowland lactating women who did not took vitamin A immediately after delivery or within the first 8 weeks after delivery were more likely to be undernourished than those lactating women who took vitamin A immediately after delivery or within 8 weeks after delivery. This can be strongly argued that Vitamin A is essential for, maintain mucosal surface of the respirator, gastrointestinal and for growth, reproduction and immunity [33, 34].

According to the Essential Nutrition Action (ENA), taking at least two additional meals per day during lactation is recommended for all lactating women. Good maternal nutrition is important for the health and reproductive performance of women and the health, survival, and development of their children [35]. Accordingly in the current study, lactating women from lowland who did not took any additional meal during lactation time were more likely to be chronic energy deficient as compared to lactating women from lowland who took any additional meal during their lactation time. This was again supported from the cross tabulation that beyond half of study participants from lowland and highland were never took any additional meal during their lactation time. The current finding is consistent with a study conducted in Ethiopia below three fourth’s of the study participants did not take any additional meal during their lactation time [26]. Another study conducted in rural Bangladeshi mothers, the participants were not taking any additional foods during their lactation period, moreover a study conducted in Mayan-mar, none of the women consumed dietary supplements during the lactation period [36, 37]. The probable reason for this might be due to lack of awareness of mothers taking additional meals during lactation and these mothers may not have adequate income to afford two addition meals per day during lactation time.

The risk of malnutrition among women could be affected by the number of children they ever born. In the current study, parity was another factor affecting women’s nutritional status. Those lactating women from highland who had parity 3–6 were 55% at reduced risk to be chronic energy deficient as compared to those highland lactating women who had parity less than two. This is consistent with a study conducted in Ethiopia the result showed women who have never had a child (parity 0) and women with at least five children (parity 5+) were at a higher risk of chronic energy deficiency than other women [13]. However, the current study was in contradict with a study conducted in Samre Woreda, South Eastern Tigray, Ethiopia, showed that nutritional status of study participants had no significant association with number of parity [26].

The quantity of foods consumed by mothers has a direct impact on their health and that of their children. The current finding showed that those highland lactating women who eat two times a day were more likely to be chronic energy deficient than those highland lactating women who eat three times a day. This is consistent with a study done in Bangladesh showed that more than one fifth of women could not afford two meals per day [38] and a study conducted in Erute internally displaced persons CAMP Lira- district which indicated that those women who had less frequent meals per day had a greater chance of being underweight [39]. The possible reason for this trend is the lessen calories from fewer meals taken by these individuals.

Iodine deficiency has adverse effects on all population groups, but women of reproductive ageare often the worst affected. From the result of the current study consumption of household iodized salt was significantly associated with the nutritional status of lactating women from highland. Those lactating mothers from highland who used non-iodized salt for their household consumption were more likely to be chronic energy deficient as compared to those lactating mothers who did not used salt fortified with iodine. Therefore the current finding is consistent with a study conducted in Bangladesh, which showed that almost all women who consume iodized salt shows some sign that the nutritional status of this group of women is better than those who never consumed [40].

Maternal occupation as farmer may have relationship with the nutritional status of the mother. Farm activity is characterized by heavy workload that can affect women’s nutrition and health status by increased energy use accompanied by inadequate food consumption. A heavy workload for women may lead to a poorer diet which affects women’s health and nutrition. The diet may be poor because there is less time for preparation and cooking. Women involving in agricultural activity skipped lunch because they were working in the fields the whole day. This in turn affects their nutritional status because energy intakes are often below recommended values, as it was found from the study large numbers of participants from highland were farmers and they were also underweight.

Dietary diversity intakes of the participants were below the recommendation that might lead the study subjects to poor nutrient intake which in turn affects their nutritional status. Thus majority of the participants both in the lowland and highland had inadequate nutrient intake, since their dietary diversity was less than 5 food groups.

The prevalence of chronic energy deficiency in both comparative study groups was very high and a serious public health problem. The potential risk factors that affect the nutritional status of the participants from lowland were, age of the lactating women, partners occupation, taking vitamin A immediately after delivery or within the first 8 weeks after delivery, taking any additional meal during lactation time. Whereas number of children ever born (parity), number (frequency) of meals per day, use of iodized salt for household consumption were potential factors that affect nutritional status of study participants in the highland communities.