Risk Factors of Birth Asphyxia among Newborns at Debre Markos Comprehensive Specialized Referral Hospital, Northwest Ethiopia: Unmatched Case-Control Study

Background: Despite a global decline in under-five deaths, the neonatal mortality rate remains slow in developing countries and birth asphyxia remains the third cause of neonatal deaths. Globally, neonatal deaths accounts for 45% of under-five deaths, birth asphyxia causes 23-40% of neonatal deaths in Ethiopia. There is limited data on risk factors of asphyxia in Ethiopia, particularly in the study area. Therefore, this study aimed to identify the risk factors of birth asphyxia among newborns. Methods: This research followed a hospital-based unmatched case-control study design at Debre Markos comprehensive specialized referral hospital, Northwest Ethiopia, among 372 newborns (124 cases and 248 controls). Data were collected by interviewing index mothers and chart review using a pre-tested questionnaire. Then it was entered in Epi-data version 3.1 and transferred to STATA version 14.0 for analysis. Bivariate and multiple variable logistic regression were carried out to the possible risk factors. Finally, statistical significance was declared using adjusted odds ratio with 95% CI and p-value <0.05. Results: Prolonged labor >12, meconium-stained amniotic fluid, assisted vaginal delivery, gestational age < 37 weeks, noncephalic presentation, comorbidity, birthweight<2500grams were found to be significant factors of birth asphyxia. Conclusion: In this study, Prolonged labor >12 hours, meconium-stained amniotic fluid, assisted vaginal delivery, gestational age < 37 weeks, non-cephalic presentation comorbidity, fetal distress, birthweight<2500grams were found to be risk factors of birth asphyxia were risk factors of birth asphyxia. Therefore, to reduce neonatal mortality associated with birth asphyxia, attention should be given to holistic pregnancy, labor and delivery care, and post-natal care. Moreover, interventions aimed at reducing birth asphyxia should target the identified factors. Study design, period and setting: Institutional-based unmatched case-control study design was conducted considering neonates with asphyxia as cases and those without asphyxia as controls among newborns from August 1/2019 to October 2019 at Debre Markos referral hospital which is located in Debre Markos town, East Gojjam Zone, Amhara regional state. The town is found 299 km north west from Addis Ababa, capital city of Ethiopia. According to information obtained from the administrative offices of Debre Markos comprehensive specialized referral hospital, they provide different services in the outpatient department, inpatient department and operation room theatre department. The hospital serves for more than 3.5 million populations in the catchment area and it has more than 30 beds in NICU with annual admission of more than 2800 neonates of which, more than 770 neonates are by birth asphyxia. There are five pediatricians and 21 nurses in NICU. In obstetrics and gynecology ward there 7 gynecologists and 45 midwifery professionals with the annual delivery 6734 neonates. Study participants: The study population was both neonates with asphyxia and those without asphyxia admitted to neonatal intensive care units (NICU) in Debre Markos referral hospital. All live newborns who were born after 28 weeks of gestation were screened for eligibility. The study classified participants into cases and controls. Newborn babies with < 7 APGAR scores at 5 minutes were defined as having asphyxia at birth (cases), while newborn babies with ≥7 APGAR scores at 5 minutes were considered non-asphyxiated (controls). The research included newborns who met the case-control definition and whose mothers gave informed consent. The study excluded newborns who had met the case- control definition but whose mothers had not been interviewed voluntarily. Newborns with one or more life-threatening malformations, including congenital cyanotic heart defects and hydrops, and other severe birth defects also excluded. Besides, newborns with no recorded of 5th minute APGAR score and who were not diagnosed as birth asphyxia were excluded from the study. Sample size calculation and sampling techniques: The sample size was estimated using an unmatched case-control formula (Kelsey), which assumed a confidence level of 95%, power (80%) and case-control ratio of 2, and odds ratio (OR) of 2 to be defined as significant using Epi-info7. The proportion of non-asphyxia neonates (controls) (31.3%) and asphyxia cases (60.0%) with prolonged labor exposure (>12 hours) were obtained from a previously conducted study (17) and the total sample size was obtained by adding 10% nonresponse rate, which was 372 (124 cases and 248 controls). Cases and controls were recruited on a continuous basis between August 1, 2019 and October 30, 2019 until the appropriate sample size was reached for both groups. Data collection tool and procedure: Data were collected using a pre-tested and adapted standardized questionnaire (18) it was administered by interviewers, observational and chart review was used to gather data on sociodemographic maternal variables, variables related to obstetric history (mother’s age, education, pregnancy number, parity, history of pregnancy outcome, gestational age; antepartum factors (prime parity, maternal fever, pregnancy-induced hypertension, anemia, peripartum hemorrhage, history of previous neonatal deaths); intrapartum factors (mal-presentation, prolonged labor, meconium-stained liquor, pre-eclampsia, eclampsia, augmentation of labor, complicated labor, mode of delivery); fetal factors (sex, birth weight, the maturity of the newborn). The tools were prepared in English and translated to Amharic; eventually, it was translated back to English to check the consistency. Birth asphyxia was determined using APGAR score which consisted of five components such as appearance (color), pulse (heart rate), grimace (reflexes), activity (muscle tone) and respiration, each with a score of 0, 1, or 2. A score of (≥7) showed no asphyxiation of a newborn while a low score (< 7) revealed an asphyxiated newborn (17). Data quality control: The quality of the data was ensured by using properly designed data collection tools. Training was given for data collectors and supervisors for two-days on data collection procedures, techniques and methods. Prior to data collection, the questionnaire was tested in five percent (7 cases and 14 controls) at Lumame hospital to verify the questioner's accuracy. Clarification of question and time to complete the questionnaire was assessed. The supervisors and the principal investigator reviewed and updated the computed questionnaires every day, and the data collectors provided the necessary input for the next morning before the actual procedures began. Study variables: Birth asphyxia was the dependent variable. While the independent variables include maternal characteristics and variables related to obstetric history (mother's age, education, pregnancy number, parity, history of pregnancy outcome (singleton or multiple ), gestational age; antepartum factors (prime parity, maternal fever, pregnancy-induced hypertension, anemia, peripartum hemorrhage, history of previous neonatal deaths); intrapartum factors (mal-presentation, prolonged labor, meconium-stained liquor, pre-eclampsia, eclampsia, augmentation of labor, complicated labor (cord prolapse), mode or type of delivery); fetal factors (sex, birth weight, the gestational age of the newborn). Data analysis: Data was entered in Epi-data version 3.1 and transferred to STATA version 14.0 for analysis. Using descriptive statistics, socio-demographic factors, antepartum, intrapartum, and neonatal- related factors are presented using frequency tables, figures, and percentages. In the second stage, bivariate logistic regression was used to identify possible factors of candidate variables with a p-value <0.2 for the final model. The model fitness test was carried out using the Hosmer – Lemeshow test, which is a statistical test for fitness for logistic regression models. Finally, the multivariable logistic regression model was fitted to identify significant risk factors of birth asphyxia through a backward stepwise method, risk factors of birth asphyxia among newborns were determined using their adjusted odds ratio with 95% CI and p-value < 0.05. The following operational definitions are used Birth asphyxia: Neonate failure to start and sustain sufficient respiration within 5 minutes of birth with an Apgar score below 7 (19). Cases (asphyxiated newborns): all neonates diagnosed with asphyxia by the attending health professionals using an Apgar score of less than 7 at 5 minutes after birth were considered as cases. Controls (non-asphyxiated newborns) – all neonates diagnosed as non-asphyxiated by the attending health professionals using an APGAR score of more than 7 at 5 minutes were considered as controls. Ethics Approval and Consent to Participate: The ethical clearance letter has been received from the research and review committee from college of health sciences, Debre Marks University. Additionally, prior to beginning data collection permission was obtained from the hospital authority. Finally, informed written consent was received from each participant mothers after explaining the research objectives. The participants were briefed on the study's purpose, procedures, potential risks, and benefits. In addition, the participants were told that failure to agree or to withdraw from the study would not change or endanger their access to treatment.