Admissions for hypoglycaemia after 35 weeks of gestation: perinatal predictors of cost of stay

BACKGROUND: Hypoglycaemia accounts for approximately one tenth of term admissions to neonatal units, can cause long-term neurodevelopmental impairment and is associated with significant burden to the affected infants, families and the health system.

OBJECTIVE: To define the prevalence, length and cost of admissions for hypoglycaemia in infants born at greater than 35 weeks gestation and to identify antenatal and perinatal predictors of those outcomes.

MATERIAL AND METHODS: This was a retrospective audit of infants admitted for hypoglycaemia between 1/1/2012 and 31/12/2015, in a level three neonatal intensive care unit at King's College Hospital NHS Foundation Trust, London. The main outcome measures were the prevalence, length and cost of admissions for hypoglycaemia and antenatal and postnatal predictors of the length and cost of stay.

RESULTS: There were 474 admissions for hypoglycaemia (17.8% of total admissions). Their median (IQR) blood glucose on admission was 2.1 (1.7-2.4) mmol/L, gestation at delivery 38.1 (36.7-39.3) weeks, birthweight percentile 31.4 (5.4-68.9), their length of stay was 3.0 (2.0-5.0). Admissions equated to a total of 2107 hospital days. The total cost of stay was 1 316 591 GBP. The antenatal factors associated with admission for hypoglycaemia were maternal hypertension (19.8%), maternal diabetes (24.5%), fetal growth restriction (FGR) (25.9%) and pathological intrapartum cardiotocograph (23.4%). In 13.7% of cases there was no associated pregnancy complication. Multivariate logistic regression analysis demonstrated lower gestational age, z-score birthweight squared, exclusive breastfeeding and maternal prescribed nifedipine were independently associated with the length and cost of stay.

CONCLUSIONS: Hypoglycaemia accounted for approximately one fifth of admissions after 35-week gestation. Lower gestational age and admission blood glucose, low and high z-score birthweight, maternal nifedipine and exclusive breastfeeding are associated with longer duration of stay.