Low birth weight (LBW) remains a major public health concern globally, especially in Lower and Middle Income Countries (LMIC) (1). The World Health Organization (WHO) LBW as a weight at birth of less than 2,500 grams (or 5.5 pounds) (1). The weight of a baby at term depends on its gestational age and the rate of fetal growth in the uterus. An infant’s birth weight is the first weight measured after birth, ideally within the first few hours after birth, before considerable postnatal weight loss occurs (2). Globally, it is estimated that 15–20 percent of all births are LBW, resulting in over 20 million new cases born each year and 60–80% of newborn deaths (3, 4). It is estimated that LMIC accounts for more than 90% of LBW cases worldwide, with 72 and 22% born in Asia and Africa, respectively (5).

Evidence shows that babies with a LBW are associated with adverse physiological, psychological, and functional health and development into adulthood (6, 7). For instance, LBW babies are more likely to have stunted growth and poor cognitive development in their early years (8). As a result, LBW results in reduced productivity in education, economic, and other activities. The risk of developing cardiovascular diseases, diabetes and hypertension is higher later in their life (9, 10). It also contributes to the inter-generational cycle of poverty, malnutrition, and diseases often experienced in LMIC (9, 11). Furthermore, LBW has economic consequences not only the family members but often the entire community because of increased medical costs, time spent in hospitals, and time away from work. The identification of potentially modifiable risk factors for LBW is required for developing effective prevention interventions in LMIC.

In LMIC, LBW is common among mothers with further socio-economic disadvantage and poor access to health care, associated with periconceptual stressors (12). These inequalities are associated with maternal risk factors for LBW including inadequate nutrition, restricted blood supply to the uterus as a result of stress, specific and non-specific illnesses, and complications during pregnancy (13, 14). For instance, lack of support for stress management during pregnancy is exacerbated by socio-economic disadvantage and poor health behaviors (9, 15). If neglected, the health and well-being of expectant mothers is likely to exacerbate the risk of LBW for their newborns (16, 17).

Published literatures indicated that there are evidences showing LBW is common and plays a substantial role in neonatal, infant, and under-five mortality (13). It is increasingly being used to predict prenatal mortality and morbidity, particularly in Sub-Saharan African countries, including Ethiopia (13). In Ethiopia, the mini demographic health survey in 2019 reported a neonatal mortality rate of 30 per 1,000 live births (17, 18). Reducing the rate of LBW is vital for reducing child mortality (19), which is critical to the future development of LMIC. Nearly 3 million of these deaths occur within the first four weeks of life, contributing considerably to neonatal mortality rates that have nearly doubled in recent years (20). Each year, Ethiopia loses approximately 27,587 neonates due to LBW, accounting for 4.5% of total neonatal mortality (19). The prevalence of LBW is as high as 18% in Ethiopia, which indicates that almost one in five neonates weighs less than the normal range (21). Furthermore, those with LBW but survive the neonatal period are more likely to develop chronic disease in adulthood, such as cardiovascular diseases and diabetes (1, 9).

A range of maternal risk factors for LBW in LMIC have been implicated but are poorly understood. Research shows that high maternal blood pressure during pregnancy, maternal age, the mother’s educational status, insufficient gestational weight gain, not taking iron and folic acid during pregnancy, maternal Middle Upper Arm Circumference (MUAC) of <23 cm reflecting nutritional status during famine (22, 23), lack of nutritional counseling during pregnancy, anemia, incomplete antenatal care, preterm birth, lack of additional food intake during pregnancy, and a history of intimate partner violence are among the risk factors for LBW (11, 24, 25). However, the strength and independence of these associations are not well-defined. This is because, most of the pocket studies were cross-sectional studies, where the temporal relationship of the predictor variables and outcome variable is less identified, and also no comparison group identified in cross-sectional studies. Therefore, the current study aims to identify the maternal risk factors associated with LBW in Ethiopia.

We present this paper according to the Journal’s formatting requirements and STROBE guidelines for reporting case–control studies.

The collected data was coded and checked for completeness and consistency. Identified errors during this time were adjusted after a review of the original data using the code numbers. Data were entered into EpiData software version 3 and exported to the Statistical Package for Social Science (SPSS) software version 26 for cleaning and analysis.

Frequency distribution and summary statistics such as mean and standard deviation were computed for cases and control groups. Model fitness was assessed by using the Hosmer and Lemeshow goodness of fit test (p = 0.56), showing the model was a good fit for the data. The bivariable regression model was carried out, and variables having a value of p less than or equal to 0.25 were entered into the multivariable logistic regression model. Multi-collinearity was checked using Variance Inflation Factor (VIF), with a maximum of 1.9, indicating no multicollinearity. The multivariable logistic regression model was built using the enter method in the final model. Finally, a value of p less than 0.05 with its 95% Confidence Interval (CI) was used to declare the statistical significance.

Low birth weight is still significant in Ethiopia. The present study tried to assess maternal risk factors associated with low birth weight among women who gave birth at public health facilities of west Wollega zone, Ethiopia. The findings of the study identified that nutritional counseling during pregnancy, frequency of antenatal care, maternal under nutrition, and maternal stress during pregnancy were found to independently predicted low birth weight. All of the identified risk factors can be averted through integrated and focused maternal health care services before, during and after pregnancy.

One of the risk factors for the LBW in this study was lack of nutritional counseling during pregnancy. Women who did not receive nutritional counseling during pregnancy more than twice to give low birth weight babies when compared to their counter parts. This finding was in line with the study from Dire dawa town, Ethiopia (30), North shoa (31), Gamo Gofa (32), and Hawassa university comprehensive specialized hospital (33). This could be due to the fact that nutritional counseling may assist women improving their feeding behavior or women’s dietary practice, and thus their nutritional status. Counselled women were more likely to have appropriate dietary practice than their counterparts. Taking an adequate amount and a good quality diet is a direct determinant of gestational weight gain. Receiving dietary counseling and taking an adequate and balanced diet had a positive impact on the mothers as well the fetus’s weight during pregnancy. Moreover, healthy and optimal intrauterine fetal growth relies heavily on maternal nutrient status (34). According to the systematic review and meta-analysis of five cohort studies, the birth weight of the offspring was significantly reduced in those who had higher exposure to acrylamide when compared to those who had lower exposure to it (35). This is because, maternal acrylamide consumption is positively related with umbilical cord estradiol levels, which may influence children’s growth (36).

This study shows, the lower the MUAC of the mother less than 23 cm, the higher the chance of LBW of the fetus. This finding is consistent with the findings of study done in Ethiopia and Malaysia (37–39). Even though either acute or chronic maternal malnutrition has direct effect on the birth weight of a baby, acute maternal malnutrition has more pronounced effect. This is due to the fetal development in the uterus is strongly influenced by mother nutritional status (9). When mothers are nutritionally deficient, the fetus’s intrauterine growth is inhibited, resulting in LBW (40). Nutritional status was examined in other research as additional meal consumption and anemia throughout pregnancy, and both characteristics were found to be predictors of low birth weight (38, 40). But in the present study, the presence of anemia did not show significant association with low birth weight.

Low birth weight has been linked to moderate to high levels of stress among pregnant women. According to the present study, mothers who were subjected to severe stress during pregnancy had about three times higher odds of having low birth weight infants compared to their counterparts. This result is supported by study conducted in Ghana and China (7, 26). This could be because blood supply to the placenta decreases during times of stress. Stress increases in cortisol, norepinephrine and inflammation which affect the fetal environment and have implications for maternal and infant health. Prenatal stress exposure is negatively associated with fetal physical development. Exposure to prenatal maternal cortisol appears to be an important factor linking gestational stress to LBW and stunting. Elevating free circulating cortisol may pass through placenta, prevent fetal growth rate and reduce birth weight of the prenatally stressed offspring (26). In response to stress, blood flow to the uterus is restricted and the fetus receives fewer nutrients, which might result in LBW (41).

The odds of LBW among newborn from mother who had antenatal care less than 4 visits were 2.8 times higher as compared to their counter parts. This result is in agreement with the study conducted in Iran and Ethiopia (39, 42). The finding was also consistent with study conducted in six-middle and low income countries (41). This could be due to the fact that mothers may receive adequate nutritional counseling during antenatal care visit which enhances their nutritional intake and reduces the risk of low birth weight. The other possible explanation for this might be, there will be a chance for monitoring of fetal wellbeing and timely intervention of feto-maternal problems when there is adequate ANC visit. Additionally, there is routine nutritional and medical advice, as well as the provision of iron folic acid supplementation which help in growth of the fetus.

A vital aspect for optimal pregnancy outcomes is family support, which includes assistance from family, the baby’s father, and general functional support (25). According to a Ghanaian study, the social support system related to the mother’s living situation during the pregnancy, women who lived with extended family during pregnancy had higher likelihood of giving birth to LBW than women who lived with intimate partner (7). But our study did not find any significant association between maternal living status during pregnancy and low birth weight.

When using this study finding, the following limitations should be taken in to account. The study was conducted at health-facilities. Therefore, the findings might not be generalizable to the total population. Again, the sample size used was also smaller, which might hinder the findings not nationally representative. Because some of information was recorded as reported by the women, the result might be affected by recall bias. Moreover, the maternal stress identified as the predictor of LBW was not studied at which gestational trimester and whether the stress is acute or chronic one. Again, the study did not include the environmental factors, particularly residential greenness, which has positive association with the birth outcome (43).

The finding of this study revealed that, lack of nutritional counseling, maternal malnutrition (MUAC <23 cm), maternal stress during pregnancy and Antenatal follow up <4 visit were significant predictors of with low birth weight. Generally, almost all maternal risk factors identified in this study are modifiable risk factors. The study findings call upon the need of psychological support of the mothers during pregnancy, enhancing integrated nutritional counseling and intended frequency of ANC follow-up. Further study also is recommended to identify the causal pathway of maternal stress and the neonatal birth outcome in Ethiopia using clinical trial study.

The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.

The study was ethically approved by the Research Ethics and Review Committee of Wollega University with the reference number, WU/RD/534/2014. The studies were conducted in accordance with the local legislation and institutional requirements. Written informed consent for participation in this study was provided by the participants' legal guardians/next of kin.

BRF, YM, and FF developed the concept and reviewed the literature. YM and BRF performed the data analysis. YM, BRF, BB, EA, and FF discussed the findings and proofread the manuscript for spelling and grammar. BRF wrote the first draft. BB and EA reviewed the manuscript. All authors contributed to the article and approved the submitted version.