Clinical Guidelines (Nursing)

Environmental humidity for premature neonates

  • Note: This guideline is currently under review.  


    Infants born at <30 weeks gestation have an immature epidermis and stratum corneum and are at an increased risk of transepidermal water loss (TEWL).  The use of environmental humidity assists to reduce TEWL and in turn supports temperature regulation, fluid and electrolyte management and skin integrity.


    The aim of this guideline is to provide all clinical staff with the criteria, settings and weaning regime required for the provision of environmental humidity for preterm infants.  Correct management of environmental humidity assists to improve skin integrity, thermoregulation and fluid and electrolyte balance.

    Definition of terms

    Environmental humidity: The percentage of ambient humidity surrounding the baby
    Transepidermal water loss (TEWL): The evaporative loss of water from the immature epidermal layer of the skin


    All infants <30 weeks gestation AND <2 weeks of age should be nursed in an incubator with environmental humidity and servo control thermoregulation functions.  



    Environmental humidity should be delivered via an incubator, and commenced as soon as possible.  The water reservoir within the incubator should be filled with sterile water to prevent bacterial colonisation, and regularly checked and refilled as required.  Gradual weaning should occur with staged reductions in the humidity percentage after 7 days of life.  

    Settings and Weaning

    The impact of TEWL and serum sodium levels should be regularly assessed, with hypernatraemia an indicator of excessive TEWL, or a water deficit, that signifies a requirement for greater humidification percentages.  After successful staged reductions, environmental humidity should then be ceased after 2 weeks of life, as the epidermis will then have matured to act as an effective barrier.  The table below demonstrates the commencing and weaning process for humidification.  

    It is important to note that the duration and percentage of environmental humidity may depend on the neonate’s gestational age, serum sodium levels, fluid balance and skin condition – all of which should be discussed and assessed during the medical ward round.

    Day of Life Environmental Humidity (%)
    1-7 80%
    8 75%
    9 70%
    10 65%
    11 60%
    12 55%
    13 50%
    14 45%
    15 CEASE

    Documentation within EMR

    • Hourly set and actual environmental humidity levels (%)
    • Hourly set and actual servo control temperature 
    • Four hourly axillary temperatures 
      • On commencing environmental humidity, perform hourly until stable
      • Increase frequency if outside of normothermia
    • Accurate fluid balance

    Special Considerations

    • Minimising the opening of doors
    • Change the incubator weekly.  Document this date both within EMR, and on by placing a sign on the cot
    • Environmental humidity does not exclude a haemodynamically stable infant from participating in skin-to-skin care (SSC). The potential increase in TEWL during SSC is small and transpires to marginal clinical importance
    • While it is possible to provide a degree of humidification while nursed on a radiant warmer, there remains a significant increase in TEWL.  Furthermore, this method poses potential problems regarding an accumulation of carbon dioxide for non-ventilated infants.  On occasions where incubator care is not possible, i.e., imminent surgery, the infant should be transferred from the radiant warmer back into a pre-prepared and humidified incubator as soon as possible.  
    • Once humidification has been ceased, change the incubator and remove the water tray to prevent microbial build up.  The humidity chamber is sent to CSSD and the heater unit is to be processed by the Butterfly Ward PSA's (with care taken when removing the heater unit as it may still be hot). 
    • Avoiding excess rain-out by wiping the inside of the incubator with a dry cloth
    • Ensure families understand the rationale for environmental humidity and facilitate interaction where able. 

    Companion Documents 


    Humidification via a Radiant Warmer
    Skin-to-Skin Care for the Newborn
    Thermoregulation in the Preterm Infant


    • Argen, J, Sjors, G & Sedin, G (2006), ‘Ambient Humidity Influences the Rate of Skin Barrier Maturation in Extremely Preterm Infants’, The Journal of Pediatrics, 148(5): 613-617.
    • Allwood, M (2011), ‘Skin Care Guidelines for Infants Aged 23-30 Weeks’ Gestation: a Review of the Literature’, Neonatal Paediatric and Child Health Nursing, 14(1): 20-27.
    • Flenady, V & Woodgate, PG (2009), ‘Radiant Warmers versus Incubators for Regulating Body Temperature in Newborn Infants (Review)’, The Cochrane Collaboration, Wiley Publishers.
    • Gomella, T & Cunningham, M (2013), ‘Body Water, Fluid and Electrolytes’, (pp68-76), Neonatology: Management, Procedures, On-Call Problems, Diseases and Drugs, 7th edition, McGraw-Hill Education, USA.
    • Gomella, T & Cunningham, M (2013), ‘Management of the Extremely Low Birthweight Infant during the First Week of Life’, (pp163-174), Neonatology: Management, Procedures, On-Call Problems, Diseases and Drugs, 7th edition, McGraw-Hill Education, USA.
    • Mercy Hospital for Women Clinical Guideline (2009), ‘Thermoregulation of the Neonate’.
    • Royal Women’s Hospital Clinical Guideline (3rd April 2014), ‘Ambient Humidity in NISC’.
    • Sinclair, L & Sinn, J (2009), ‘Higher versus Lower Humidity for the Prevention of Morbidity and Mortality in Preterm Infants in Incubators’, Intervention Protocol, Cochrane Neonatal Group.
    • Smith, J – Royal Prince Alfred Hospital Clinical Guideline (2010), ‘Small Baby Guideline: Management of Infants <27 Weeks Gestation’.
    • Woods Blake, W & Murray, J (2006), ‘Heat Balance’ in G. Merenstein & S. Gardner (eds), Handbook of Neonatal Intensive Care, (pp 122-138), 6th edition, Mosby Elsevier, USA.

    Evidence table

    Environmental humidity for premature neonates evidence table

    Please remember to read the disclaimer

    The development of this nursing guideline was coordinated by Tara Doyle, CNS, Butterfly Ward, and approved by the Nursing Clinical Effectiveness Committee. Updated August 2016.