Postnatal growth curves of very low birthweight Japanese infants

Growth Patterns of Neonates Treated with Thermal Control in Neutral Environment and Nutrition Regulation to Meet Basal Metabolism

Little is known about the growth patterns of low birth weight neonates (<2500 g) during standardized thermal control and nutrition regulation to meet basal metabolism requirements compared to those of non-low birth weight neonates (2500 g and above). We retrospectively identified 10,544 non-low birth weight and 681 low birth weight neonates placed in thermo-controlled incubators for up to 24 h after birth. All neonates were fed a 5% glucose solution 1 h after birth and breastfed every 3 h (with supplementary formula milk if applicable) to meet basal metabolism requirements. Maximum body-weight loss (%), percentage body-weight loss from birth to peak weight loss (%/day), and percentage body-weight gain from peak weight loss to day 4 (%/day) were assessed by multivariable linear regression. Overall, the growth curves showed a uniform J-shape across all birth weight categories, with a low mean maximum body-weight loss (1.9%) and incidence of neonatal jaundice (0.3%). The body-weight loss patterns did not differ between the two groups. However, low birth weight neonates showed significantly faster growth patterns for percentage body-weight gain: β = 0.52 (95% confidence interval, 0.46 to 0.58). Under thermal control and nutrition regulation, low birth weight neonates might not have disadvantages in clinical outcomes or growth patterns.

Fluid and electrolyte balance in extremely preterm infants <24 weeks of gestation in the first week of life

BACKGROUND

Extremely preterm infants, especially those <24 weeks of gestation, displayed extremes in changes of fluid/electrolyte balance. The purpose of the present study was to retrospectively investigate abnormalities in fluid/electrolyte balance during the first postnatal week.

METHODS

Of 32 subjects admitted during 20 years, 17 infants with no severe complications were examined, and 72 appropriate-for-dates infants at 24-28 weeks of gestation were taken as controls. The subjects were managed in closed incubators in a highly humidified environment and fluid/electrolyte balances were monitored in retrospect.

RESULTS

The subjects had higher urine contents, while the insensible water loss was higher than in controls. As for weight loss, no remarkable changes were noted between the two groups. On day 4 and thereafter, serum Na(+) levels were high, indicating a high complication rate of hypernatremia without differences in hyperkalemia. The decrease in blood base excess was rapid, requiring supplementation of sodium bicarbonate up to postnatal day 5 in all preterm infants.

CONCLUSION

Due to the relatively higher urine output and insensible water loss in extremely preterm infants during postnatal week 1, higher water intake was required. As such, metabolic acidosis was bound to have occurred.