Neonatal mortality, which is defined as death within the first 28 days of life, is a crucial indicator for the health and wellbeing of newborns and is increasingly playing a significant role in the total under-five mortality rate. As a result, health officials are paying special attention to neonatal deaths (1). It can be further classified into late newborn fatalities (7–27 days) and early neonatal deaths (0–6 days), which occur after the seventh day but before the 28th day of life (2). The neonatal period, which lasts for the first 28 days of a neonate's existence, is the most dangerous stage of life because a baby is especially prone to making many of the physiological changes required for life outside the uterus at this time (3). The neonatal period is associated with an average global rate of 18 deaths per 1,000 live births (4) and 3–4 million global deaths per year where 99% of them was in low to middle income countries (5).

Despite a continuous decline in under-five mortality, approximately 7,000 newborns die each day, according to a 2017 WHO report (6, 7). However, the global neonatal mortality has significantly decreased from 5 million in 1990 to 2.4 million in 2019, newborn death still accounts for 47% of all deaths among children under the age of 5, with nearly one-third dying on the day of birth and nearly three-quarters dying within the first week of life (8). Furthermore, the evidence from Inter-Agency Group for Child Mortality Estimation reported that around 30 million neonates will die before their fifth birthday between 2017 and 2030 (9).

The burden of neonatal mortality is high in low- and middle-income countries (LMICs) than high-income countries. sub-Saharan Africa and Asia have the highest mortality rates. In the WHO Regions of Africa (28%) and South-East Asia (36%), neonatal mortality rates are two thirds higher (10). From sub-Saharan African countries, Ethiopia had the fifth-highest rate of neonatal deaths in 2016 (90/1,000) (11). Nearly 1 and 2 million deaths occur on the day of delivery and in the first week of life, respectively, and neonatal deaths account for 40% of all mortality of children under the age of 5 (12). When compared to the remainder of the month, where 50% of deaths occur and 75% occur throughout the first 7 days of life, a newborn has a 500 times higher chance of dying within the first 24 h (13). The rate of neonatal mortality is intrinsically linked to the health of the mother and the care she receives before, during and immediately after giving birth. Asphyxia and birth injuries usually result from poorly managed labor and delivery and lack of access to obstetric services (14, 15).

Preterm, prenatal asphyxia, and infections like sepsis, meningitis, and pneumonia account for more than 80% of newborn deaths (16). Particularly in Ethiopia, preterm birth, intrapartum problems, and infections account for roughly 90% of all fatalities. For 31% of neonatal deaths in Ethiopia, neonatal infection is the major contributing factor (17). Neonatal illnesses are challenging to treat with a single therapeutics or clinical interventions but it requires a systematic approach (16). Moreover, offering a continuum of care from pregnancy through birth and the immediate postpartum period, immediate causal factors could be readily avoided (18, 19). In addition, reduced newborn morbidity and mortality can be achieved through skilled care during pregnancy, labour, and the postpartum period (20).

The number of deaths and the percentage of neonatal deaths are predicted to increase to 69 million deaths and 52%, respectively, by 2030. Target 3.2 of the Sustainable Development Goals (SDGs) 3 shifts the focus to newborn health, with the goal of bringing the rate of neonatal mortality below 12 per 1,000 live births by 2030 (21, 22). But, on the basis of current trends more than 60 nations will fall short of SDG target by 2030. Similarly, by 2050 over half of them won't have accomplished the goal (23). Furthermore, the Mini-Ethiopian Demographic and Health Survey (EDHS) report states that Ethiopia has a neonatal mortality rate of 30% per 1,000 live births (4). Neonatal mortality increased from 28 per 1,000 live births in 2016 to 30 per 1,000 live births in 2019 according to a report from EDHS-2019 indicating NMR is still a big public health problem in Ethiopia (24).

Despite a significant reduction in maternal and child mortality in Ethiopia, neonatal deaths are still occurring in substantial numbers. A piece of evidence has also tried to indicate the problem of NMR, but the problem is quite different due to ecological factors. Additionally, previous studies were performed using a small sample size, which might lack generalizability. Thus, evidence with a cohort study design and higher sample size can provide more reliable evidence for scientific communities, as well as policy makers and decision makers. Therefore, the aim of this study was to assess the magnitude of neonatal mortality and to identify associated factors among neonates admitted in Neonatal intensive care unit in Dessie Comprehensive Specialized Hospital, Northeast Ethiopia.

Neonatal mortality remains a severe public health issue, especially in low- and middle-income countries like Ethiopia, despite numerous advancements and treatments made to increase the survival of babies. Thus, the aim of the current study was to identify magnitude and associated factors of neonatal mortality at Dessie Comprehensive Specialized Hospital, Northern Ethiopia. The magnitude of neonatal mortality among NICU admitted neonates was 10.2% (95% CI: 8.8–11.7) which was comparable with previous findings reported from 11.4% prevalence in Ethiopia (25). On the other hand, the finding of the current study was lower than the finding of previous Ethiopian studies reported (16.7%) (13) and (18.34%) (26).

Moreover, it was higher than 4.37% neonatal death reported from Ethiopia (27). The variations might be due to study setting such as this study was conducted among neonates in NICU who have high risk of death than their counterparts. In addition, the variation can be explained by differences in skill of health professionals, presence of sociocultural and socioeconomic differences across regions of Ethiopia as well as the difference in sample sizes (9, 28) and economic disparities among study participants (9, 29, 30). Moreover, difference in health seeking behavior and health service utilization such as institutional delivery by skilled care providers and health seeking for sick neonates. As the quality of care can be affected by the availability of equipment and skilled professionals, the higher magnitude of neonatal death found in this study can be claimed to be explained by this condition.

The magnitude of early neonatal death in this study was 93% which was consistent with previous finding reported from northeastern Ethiopia. This is in line with other prior studies done in Diredewa (30) and Mizan- Tapi (9). However, the finding was higher than studies in Jimma and Bahir Dar (15, 31). The possible reason of higher magnitude of early neonatal death could be due to the fact that the first few hours of age after birth are very critical to adapt the environment, simple and inexpensive measures can decrease neonatal mortality in the first 24 h of life. Likewise, high number of prematurity-related deaths (majority of which are secondary to respiratory distress syndrome), where maximum deaths occurred in the first 72 h of age. In addition, it could be due to majority of neonatal mortality in developing countries are related to conditions of labor, intra- partum and the immediate newborn care practices which could be further associated with prematurity, sepsis, respiratory distress syndrome and birth asphyxia. This again clearly pointed out that neonatal survival interventions have to target the intra-partum as well as immediate and early neonatal periods.

The risk of neonatal mortality was significantly associated with clinical characteristics of neonatal factors which aggravates neonatal mortality. In our study, the risk of neonatal mortality was observed to rise as complication of prematurity advances, it was significantly associated with the magnitude of neonatal death (P < 0.009). Of 18.3% of the study subjects who were complication of prematurity, 14.5% of neonates were dead, this is due to the fact that, premature neonates are at higher risk of dying due to complications such as respiratory problems, feeding difficulties, poor regulation of body temperature and recurrent infections (32).

Neonates admitted to neonatal intensive care unit with birth asphyxia had 3.595 time at risk of dying than their counterpart. This could be due to the fact that oxygen deficit at delivery (birth asphyxia) can lead to severe hypoxic ischemic organ damage in newborns followed by a fatal outcome or severe life-long pathologies. This finding is consistent with a study done in Somalia region (33). This difference might be due to health service utilization, study period and sample size variations. In premature neonates’ organs are not enough matured and one organ is likely to also affect the function of other organ, as a result of this the outcome of neonates was evolving and death.

The findings of this study indicate that the risk of neonatal death is significantly higher among neonates diagnosed with neonatal sepsis compared to those without sepsis. This may because of sepsis can rapidly progress in neonates, causing severe systemic inflammation and multi-organ failure, which can overwhelm their ability to cope. Moreover, the subtle symptoms of sepsis may be mistaken for other conditions, leading to delayed recognition and treatment, ultimately resulting in worse outcomes. Additionally, these findings align with existing literature that identifies neonatal sepsis as a significant contributor to neonatal mortality (34–36).

Moreover, the risk of neonatal death was significantly higher in neonates who had respiratory distress syndrome (P = 0.011) than neonates who haven't respiratory distress syndrome. This could be due to the fact that, respiratory distress significantly increases neonatal mortality due to factors like insufficient surfactant, leading to lung collapse, and impaired gas exchange. These issues can cause severe hypoxemia, acidosis, and multi-organ dysfunction, ultimately increasing the risk of death, especially in premature infants. The study was identified based on the documented data and could not display all factors that were not documented in the patient's files such as parents’ educational status, wealth index, training and educational status of health professional providing services, infection prevention practices. Thus, variations in physicians' clinical diagnosis, completeness and quality of the recorded information were limitations of the study.

The study revealed that the magnitude of neonatal mortality was high which alarms the need of immediate collaborative actions for reduction of the burden particularly avoiding on the causal factors such as prematurity, sepsis and birth asphyxia which leads adverse birth outcomes. The majority of neonatal mortality was occurred in the first week of life. Therefore, maternal counseling, giving focused ante natal care as well as behavior change communications might be considered to promote positive behaviors are recommended to avoid the leading causes of neonatal mortality.