Neonatal Mortality is Modulated by Gestational Age, Birthweight and Fetal Heart Rate Abnormalities in the Low Resource Setting in Tanzania – a Five Year Review 2015-2019

Background: Neonatal mortality (NM) remains a significant problem in low resource settings. Birth asphyxia (BA) and prematurity contribute significantly to NM. The study objectives were to determine first, the overall NM as well as yearly neonatal mortality rate from 2015 to 2019. Second, the impact of decreasing GA (<37 weeks) and BW (<2500 grams) on NM. Third, the contribution of intrapartum and delivery room (DR) factors and in particular fetal heart rate abnormalities (FHRT) on NM <7 days. Methods Retrospective cohort study. Labor and delivery room data were obtained from 2015 to 2019 and included BW, GA, fetal heart rate (FHRT) abnormalities, bag mask ventilation (BMV) during resuscitation, initial temperature, antenatal steroids use. Outcome was binary i.e. either death < 7 days or survival. Analysis included t tests, odds ratios (OR) and multiple logistic regression Results The overall neonatal mortality rate was 18/1000 livebirths over the five years. NM was significantly higher for newborns <37 versus ≥37 weeks, OR 10.5 (p<0.0001) and BW <2500 versus ≥2500g OR 9.9 (p<0.0001). For infants <1000g / <28 weeks, the neonatal mortality rate was ~ 588/1000 livebirths. Variables associated with NM included BW - odds of death decreased by 0.55 for every 500g increase in weight, by 0.89 for every week increase in GA, NM increased 6.8-fold with BMV, 2.6-fold with abnormal FHRT, 2.2 fold with no antenatal corticosteroid (ACS), 2.6-fold with moderate hypothermia (all <0.0001). Conclusion NM rates was predominantly modulated by decreasing BW and GA, with smaller/ less mature newborns 10-fold more likely to die. NM in term newborns is strongly associated with FHRT abnormalities and when coupled with respiratory depression suggests BA. In smaller newborns, lack of ACS and moderate hypothermia were additional contributing factors. A composite perinatal approach is essential to achieve a sustained reduction in NM.