Proportion of Low Birth Weight Infants Over 2 Weeks of Age on Fortified Human Milk and Its Relationship to Occurance of Late Onset Hyponatremia in Kenyatta National Hospital, Newborn Unit

Abstract

Introduction– The placenta efficiently mediates the transfer of nutrients and products of metabolism to the foetus. Premature delivery halts this transfer of nutrients, putting the infant at risk for extra uterine growth retardation. This risk is further increased by the high requirements for macro and micronutrients, the diminishing content of breastmilk nutrients over time and comorbidities. Sodium, which is critical for growth, is compromised by the immature gut and renal handling of salt thus putting the preterm at risk of late-onset hyponatremia and growth faltering. Objectives –The primary objective was to determine the proportion of neonates <1800g and over two weeks of age on fortified human milk in Kenyatta National Hospital, Newborn unit. The secondary objectives were to determine the prevalence of late-onset hyponatremia and assess its correlation with the fortification of human milk Methodology – A cross-sectional survey was carried out in 173 preterm neonates over the age of 14days whose birthweight was less than 1800g. Consent was obtained from the caregivers before the study questionnaire was administered. Proportion of those receiving fortification of breastmilk was determined. Prevalence of late onset hyponatremia was determined from the results of serum sodium done between ages 14 to 28 days and compared for differences between those on fortified and unfortified human milk. Data Analysis - Descriptive statistics on socio-demographic characteristics like gender, and birth weight were presented using percentages and frequencies. Continuous data on serum sodium levels was presented using medians or means (standard deviation (SD)) depending on the distribution of the variable. Prevalence was determined as a proportion of neonates with late onset hyponatremia in the sampled population with 95% confidence interval around the point estimate. Chi square test was used to assess for association of late onset hyponatremia with status of breastmilk fortification. Binary logistic regression was used to assess association of late onset hyponatremia with birthweight, gestational age and status of breastmilk fortification. Tables and graphs were used to display the Results. All analysis was performed using SPSS version 24 and p-value ≤0.05 was considered statistically significant. Results – Out of the 173 participants enrolled, 54.9%(n=95) were female and 45.1% (n=78) were male. The proportion of neonates on fortified breastmilk was 48%. The overall prevalence of late-onset hyponatremia was 56.1% and was associated with lower birth weight (p<0.001)

and lower gestation period (p<0.009). Occurrence of late onset hyponatremia was 2.6 and 6.4 times more likely in those with lower birth weight (OR 2.6 [95% CI 1.1 -6.2], p<0.035) and feeding on expressed breast milk (OR 6.4 [95% CI 3.1 – 13.1], p<0.0001) respectively. Severe late onset hyponatremia was associated with feeding on expressed breast milk (p<0.0001) Conclusion –Less than half (48%)of the low birth weight neonates (<1800g) were on standard fortification of breastmilk that was initiated late (at volumes >100mL/kg/day) and 40% of these neonates (n=60) received standard feed volumes (<180mL/kg/day). The overall prevalence of late onset hyponatremia was high at 56.1% and its severity was associated with unfortified breast milk and lower birthweight. Recommendation -Breastmilk fortification guidelines are recommended to standardize the fortification practice in the newborn unit. Regular assessment and treatment of late onset hyponatremia should be incorporated into the clinical care guidelines of low birth weight neonates