Newborn Plasma Glucose Concentration Nadirs by Gestational-Age Group

Abstract

Background: The glucose concentrations and times to nadir for newborns of all gestational ages when intrapartum glucose-containing solutions are not routinely provided are unknown. Objective: To characterize and compare patterns of initial glucose concentration nadirs by gestational-age groups. Methods: A cross-sectional cohort study of 1,366 newborns born in 1998 at the University of Arkansas for Medical Sciences, appropriate for gestational age, nonasphyxiated, nonpolycythemic, and not infants of diabetic mothers, were included. Initial plasma glucose concentrations, before intravenous fluids or feedings, were plotted against time after birth for 4 gestational-age groups (full term [FT], ≥37–42 weeks; late preterm [LPT], ≥34 and < 37 weeks; preterm [PT], ≥28 and < 34 weeks; and extremely low gestational age newborns [ELGAN], 23 and < 28 weeks of gestation). Results: ELGAN had the earliest nadir at 61 ± 4 min, followed by PT newborns (71 ± 2 min), and then LPT and FT newborns at 92–93 min. The time to nadir for ELGAN and PT newborns was significantly earlier than for FT newborns. Glucose nadir concentrations for ELGAN, PT, and LPT newborns were significantly lower than for FT newborns. LPT newborns’ pattern of glucose paralleled those of FT newborns, with values approximately 5–6 mg/dL lower during the first 3 h. Conclusion: Plasma glucose nadirs occurred at different times among gestational-age groups during the early postnatal period as follows: ELGAN < PT < LPT ≈ FT. In order to potentially prevent low glucose concentrations at the time of the nadir, exogenous glucose should be provided to all newborns as soon as possible after birth.

Reply to the Letter to the Editor “The Postnatal Glucose Concentration Nadir Is Not Abnormal and Does Not Need to Be Treated”

“…We appreciate and agree with the comments by Hay et al [1] regarding our paper, “Newborn Plasma Glucose Concentration Nadirs by Gestational-Age Group” [2]. In this study, we showed for the first time that glucose concentration nadirs for extremely low gestational age newborns (ELGANs) as well as for preterm and late preterm newborns were lower than those for full term newborns and that the time to nadir for ELGAN and preterm newborns was significantly earlier than for full term newborns.…”

Incidence and Risk Factors for Hypoglycemia During Fetal-to-Neonatal Transition in Premature Infants

“…Harris et al reported an incidence of 51% in infants ≥ 35 weeks' gestation within the first 48 h after birth (1). A recent study reported that the nadir of plasma glucose concentration in preterm infants and extremely preterm infants is after 70.5 and 60.9 min, respectively (15). Our glucose samples were taken at a mean postnatal age of 49.4 min, potentially missing the nadir of hypoglycemia and resulting in underestimation of our incidence.…”

The Postnatal Glucose Concentration Nadir Is Not Abnormal and Does Not Need to Be Treated

“…In their just published article in Neonatology [1], the authors conclude their abstract with the following sentence: “In order to potentially prevent low glucose concentrations at the time of the nadir, exogenous glucose should be provided to all newborns as soon as possible after birth.” We should like to point out that this statement is factually incorrect, misleading, and potentially harmful. If “all” newborns were to receive exogenous glucose, this would apply to the vast majority of term and even many late preterm infants who appropriately do not receive exogenous glucose and normally suckle ad lib.…”