This study was conducted to investigate the effect of pregnancy under-nutrition on low birth weight incidence in Tigrai Regional State, Ethiopia. The overall cumulative incidence of low birth weight was 14% (95%CI: 11.1%, 17.4%). The incidence of low birth weight was 18.4% (95%CI: 14.1%, 23.9%) among the exposed group and 9.8% (95%CI: 6.8%, 14.2%) among the unexposed group. The difference in low birth weight incidence between the exposed and unexposed groups was statistically significant (p-value = 0.006). Low birth weight incidence of this study was consistent with the low birth weight in Wolaita Sodo Referral Hospital 15.8%(20), Felege Hiwot referral hospital 11.6%(21), Jimma University Specialized Hospital 14.6%(22), Debre Tabor Hospital(23), EDHS 2016 Ethiopia 13%(6), systematic review and meta-analysis in Ethiopia 17.3%(24), selected countries in Africa(25), and Africa level 13.7%(26).
On the other hand, this incidence of low birth weight in our study is lower than the incidence reported from studies conducted in Debre Markos Referral Hospital 21.6%(27), Northeast India 26%(28), and Nepal 23.6%(29). Whereas, it is higher as compared to incidences reported from studies conducted in Aksum town 8.8%(30), Adwa town 10%(31), Tigrai Region 10.5%(32), Butajira General Hospital 8.9% (33), Southwest Ethiopia 10%(34), Ghana 9.7%(35), Nigeria 7.3%(36), and Iran 9%(37). The difference in incidence could be due to study design, study setting, study period, and source of information. Overall this study showed a high incidence of low birth weight which indicates poor progress to achieve the World Health Assembly (WHA) target of reducing the prevalence of low birth weight to 10.5% or below by 2025(26). It is strongly supported that a newborn’s weight at birth is an important marker of fetal health and nutrition. For instance, low birth weight newborns have a higher risk of dying in the first 28 days of life and even those who survive are more likely to suffer from stunted growth, lower intelligence quotient (IQ), and poor quality of life. Moreover, the consequences of low birth weight continue into adulthood, increasing the risk of adult-onset chronic conditions such as obesity and diabetes(26,38,39). Hence, our finding could set an alarm in seeing back to the outcome being obtained through nutrition related programs and initiatives being implemented during the critical first 1,000 days of life (window of opportunity) both regionally (Tigrai) and nationally in Ethiopia, by different stakeholders and the government sectors.
Furthermore, this study revealed that illiterate pregnant women were 1.8 times more likely to give birth to newborns with low birth weight as compared to pregnant women with the educational status of above secondary school. This finding was supported by studies conducted in South-East Ethiopia(40), North Wello zone (41), Addis Ababa(42), Ethiopia(43), Tanzania(44), Indonesia(45), and India (46). This might be because maternal education promotes a positive attitude towards health-seeking behavior, acquisition of health and nutrition knowledge, and adherence to recommended feeding practices during pregnancy (47). Again, educated mothers might have greater knowledge and utilization of modern health care services and the ability to communicate with health professionals.
Our study further indicated that pregnant women who had monthly family income less than 1500 Ethiopian birr were 1.6 times higher to have newborns with low birth weight as compared to pregnant women with a monthly income of more than 5000 Ethiopian birrs. This finding was consistent with studies conducted in South-East Ethiopia (40), Southwest Ethiopia (34), LAO (48), Ethiopia (43), North West Ethiopia (21), Southern India (46), and Bangladesh(49). Pregnant women with low income could be in a high level of stress, fatigue, and psychological distress during pregnancy which in turn could be associated with low birth weight(50). Pregnant women need two extra meals in addition to the basic three meals but pregnant women with low monthly income may not get the extra meals and their diet could be poor in terms of quantity and nutrient quality.
In our study, utilization of latrine was also a statistically significant factor for low birth weight in which pregnant women who utilized latrine were 53% less likely to have low birth weighted newborns compared to their counterparts. Similar findings were reported from other studies conducted in Southwest Ethiopia(34), India(51). Poor or no utilization of latrine could reflect fecal contamination of the local environment which in turn could result in a high incidence of infectious disease and intestinal parasites, thus high levels of nutrient mal-absorption in pregnant women and possibility to have low birth weight newborns.
Finally, our study showed that pregnant women who had a diet diversity score of less than five were 1.9 times more likely to have newborns with low birth weight as compared to pregnant women who had five and above diet diversity scores. This finding was consistent with findings of other studies conducted in rural Ethiopia (18), LAO (48), West Ethiopia (52), Mumbai(53), and Ghana(54). This could be justified with the diets of pregnant women in low and middle-income countries (LMICs) that are monotonous and predominantly plant-based with little consumption of micronutrient dense animal source foods, fruits, and vegetables. Hence, such poor diets diversity is likely to be deficient in multiple micronutrients which in turn affects women’s health and nutrition which can result in a negative impact of birth weight (55).
The strength of our study was its prospective nature, control of confounding factors, and low loss to follow up. Nevertheless, limitations observed in this study include; micronutrients were not measured except hemoglobin for anemia, the possibility of recall bias during the assessment of the diet diversity score using previous 24 hours recall method, caffeine from chocolate, and soft drink was not considered, and private health facilities were not included. Besides, it does not provide evidence for a causal relation. Considering these limitations, we recommend that further inference of our findings should be with caution.