Among 402 neonates under the follow up, 125 (31.09%) died during the follow-up period. The overall incidence of mortality was 53.5 deaths per 1000 neonate-days observation with (95%CI: 44.89- 63.74). This finding is higher than a study conducted in Brazil 0.95-1.38/1000 live birth (29), 0.65-0.81/1000 live birth in 2017 (16), and 9.7/1000 live birth in Southern Nepal (32). This marked difference might be attributed to a number of factors such as source population of the study participants was live birth, while the currents study was PNA, another possible justifying may be due to a study area was population based. On the other hand, the current study was intuitional based.
The proportion 31.09% was relatively comparable with studies reported from Nigeria 31% (31), Congo 28.5% (49), India 26%(23). The finding of this study was higher than the studies reported in Nigeria 18%(34), 14.7% (39), and 23% (30),Tanzania 23% (50), South Africa 13.3%(33), India 4.8%(19) and 10% (20). On the other hand, this finding was lower than the studies conducted at India 40.6(21) and Nigeria 38.7% (35). This may be due to the fact that other studies included only outborn newborns; while in this study participants were both inborn and outborn newborns. Therefore, including outborn overestimated death rate. Moreover, The discrepancy might be variation in different studies was due to different operational definitions for birth asphyxia and adopted by different researchers (30, 33, 34, 39, 50). Moreover, this high death emanated from the poor neonatal resuscitation skills, the lack of resuscitative equipment, lack of skilled manpower in neonatal resuscitation at birth and delay in transporting the asphyxiated newborn to a higher health facilities (51, 52).
Neonatal sepsis at the time of admission significantly increased the hazard of death among neonates with PNA. This finding was supported by the studies conducted in developed and developing countries (32, 38, 40, 41, 50). The possible reason might be associated with neonatal sepsis causes hypothermia/fever, poor feeding, hypotension respiratory distress, shock, multi-organ failure, and meningitis. Besides, poor quality of care and treatment delay also the major gaps of developing counties including Ethiopia. Moreover, the unnecessary overuse of antibiotics can increase the chances of severe candidiasis and multi-drug resistant organisms (53–56). These collectively resulted to have high mortality due to sepsis among neonates with PNA. This study implied that there is a clear gap in the management and prevention of sepsis. This finding emphasizes the need to improve the quality of care in health facilities, in particular, we strongly believe that achieving a high-quality intrapartum and postnatal care is required to improve neonatal health.
Preterm neonates with PNA increased the hazard of death compared to full-term births. This was in accordance with the studies conducted in Nigeria and South Asian (30, 32, 35). Higher risk of mortality among premature neonates could be explained by different factors, like newborns with GA less than 37 weeks (preterm) were higher risk to develop complications, such as, infections, hypothermia, and hypoglycemia due to limited number of immunoglobulins at birth. Another possible explanation may be due to lack of feasible, cost-effective care, such as breastfeeding support, basic care for infections and breathing difficulties were practiced in developing counties like Ethiopia (57, 58). Given these factors are the most common causes of morbidity and mortality in neonates with PNA (59–61). This implies that anticipating high-risk newborn babies and taking combined approaches to reduce the death of such physiologically and anatomically vulnerable neonates are needed (62, 63)
In the current study, hypoxic ischemic encephalopathy (HIE) stage II and III were strong (leading) independent predictors of death, that stage II and III increase the hazard of death by seven times and 17-fold respectively compared with stage I by holding another variables constant. This finding is supported by the studies conducted in Nigeria (22, 31, 34, 39), South Africa (33) and India(20, 21, 23). The possible reason might be once HIE stage II and III occur, they result in poor feeding, seizure, brain damage, and multiorgan dysfunction. In addition, due to lack of feasible, cost-effective care like therapeutic hypothermia, supportive management of seizure and adequate resuscitation in developing countries including Ethiopia (51, 64). Besides, the probability that infants with the greatest hypoxic‑ischemic brain damage will benefit least by any specific intervention (65, 66).
The collectively increased death among neonates with PNA who faced HIE Stage II and III during admission. This study implies that more attention should be focused on the early assessment of high-risk mothers and newborns and timely referral to the tertiary care center. Moreover, adequate resuscitation, therapeutic hypothermia, supportive management of seizure and fluid balance is essential in ensuring optimal outcomes (67).
In the current study, induced onset of labor increases the hazard of death by nearly four times compared with spontaneous onset by adjusting effects of other variables. This may be associated with induced labor was indicted for high-risk mothers like (Preeclampsia, eclampsia, gestational hypertension…), intrauterine growth restriction, and post -term pregnancy (68–71). As well, induction increases the greater risk for instrumental birth, postpartum hemorrhage, affects the natural process of pregnancy and labour and increases hospitalization for maternal as well as newborn. These collectively increase the risk of death among newborns with PNA (72–75).
Antepartum hemorrhage (APH) was increasing the hazard of death among neonates with PNA. This may be associated with APH increases premature delivery, low birth weight, and fetal growth retardation (76). Moreover, APH leads neonatal anemia and decreases placental perfusion as well as hypoxia then which leads to bradycardia, and multiorgan failure (76–79).
Postpartum hemorrhage (PPH) was also independent predictor of neonatal mortality among neonates admitted with PNA, which increases the hazard of death by two times compared with mother who were not faced for PPH during delivery. This may be associated with PPH management delays the time for essential newborn care as well as neonatal resuscitations. Moreover, postpartum hemorrhage is the leading cause of maternal mortality (80, 81), which also resulted neonatal death. since the survival of the mother was vital for their child survival (82, 83). This study implies that regular antenatal care, early detection of high-risk mothers, allowing them to be timely admitted for schedule, availability of blood banks, and early referral to a higher center to reduce APH and PPH related neonatal death (79, 84, 85).