Glucose Concentrations at Postmenstrual Age 36 Weeks in Very Low Birth Weight Preterm Infants

Background: Glucose disturbances are common during the first weeks of life in very low birth weight infants (VLBW;

Objectives: To describe glucose disturbances in VLBW infants at postmenstrual age (PMA) 36 weeks using continuous glucose monitoring (CGM), and to identify risk factors for these disturbances.

Methods: The LIGHT (very Low birth weight Infants, Glucose and Hormonal profiles over Time) study is a prospective observational cohort study that included 50 VLBW infants admitted to a tertiary NICU at the University hospital in Umeå, northern Sweden, during 2016-2019. Perinatal data was registered prospectively. At PMA 36 weeks, a 48-hour long CGM registration was performed in 35 (70%) of the infants. Protracted hypoglycemia and hyperglycemia episodes were defined as glucose concentrations 8 mmol/L for 30 minutes, respectively.

Results: Three infants (8.6%) experienced isolated protracted hypoglycemia, 12 (34.3%) experienced isolated protracted hyperglycemia, and 7 (20.0%) experienced both protracted hypoglycemia and hyperglycemia. Longer time in hypoglycemia at PMA 36 weeks was noted in infants with lower Apgar scores at 10 min after birth and who had prior hyperglycemia episodes. Amnionitis and prior hypoglycemia and hyperglycemia episodes were significantly associated with protracted hyperglycemia at PMA 36 weeks. Male infants spent significanly longer time in hyperglycemia at PMA 36 weeks.

Conclusions: Protracted glucose disturbances are common in VLBW infants even at PMA 36 weeks and might warrant further monitoring. Sicker infants at birth, and infants exposed to prior hyperglycemia, are at increased risk for hypoglycemia. Males and infants exposed to amnionitis and prior glucose disturbances are at increased risk for hyperglycemia.