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ABC of preterm birth : Care in the early newborn period

BMJ 2005; 331 doi: https://doi.org/10.1136/sbmj.0509320 (Published 01 September 2005) Cite this as: BMJ 2005;331:0509320
  1. William McGuire, senior lecturer in neonatal medicine1,
  2. Peter Fowlie, consultant paediatrician2,
  3. Peter McEwan, specialist registrar3
  1. 1Tayside Institute of Child Health, Ninewells Hospital and Medical School, University of Dundee
  2. 2Perth Royal Infirmary and Ninewells Hospital and Medical School, Dundee
  3. 3Ninewells Hospital and Medical School, Dundee

The first week after birth is a time of major metabolic and physiological adaptation for newborn infants. Preterm infants have to cope with additional stresses because most of their organ systems are immature or because of associated illnesses, such as congenital infection. Very preterm infants (<32 weeks' gestation) or ill infants often need intensive monitoring and support during this critical period of postnatal adaptation.

Preterm infants are susceptible to heat and fluid loss because

  • High surface area to volume ratio

  • Thin non-keratinised skin

  • Lack of insulating subcutaneous fat

  • Lack of thermogenic brown fat

  • Inability to shiver

Temperature control and fluid balance

Preterm infants are susceptible to heat and fluid loss, especially immediately after delivery and in the first few days after birth. Hypothermia is associated with increased morbidity and mortality. Trials in the 1950s showed that reducing heat loss improves survival for preterm and low birthweight infants. Measures to prevent cold stress should start immediately after delivery—for example, resuscitating newborns under radiant heaters, drying them, and wrapping them in warmed towels straight away. A randomised controlled trial showed that wrapping the infant in polyethylene immediately (without drying) is at least as effective in reducing evaporative heat loss in extremely preterm infants (<28 weeks' gestation).

Risk factors for respiratory distress syndrome

Potential adverse consequences of hypothermia

  • High oxygen consumption can lead to hypoxia

  • High use of glucose can lead to hypoglycaemia

  • High energy expenditure can cause reduced rate of growth

  • Low surfactant production can cause respiratory distress

  • Vasoconstriction may cause poor perfusion or metabolic acidosis

  • Delayed adjustment from fetal to newborn circulation

Heat and fluid loss

After admission to the neonatal unit unnecessary oxygen and energy consumption must be minimised. Several options are available for nursing preterm infants in a neutral thermal environment. Bigger and more mature infants (weighing > 1800 g) can usually maintain their body temperatures in open cots with clothing (including a hat), covers, and possibly a heated mattress. Smaller and less mature …

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