Article Text

Download PDFPDF
Respiratory function of very prematurely born infants at follow up: influence of sex
  1. M R Thomas1,
  2. L Marston2,
  3. G F Rafferty1,
  4. S Calvert3,
  5. N Marlow4,
  6. J L Peacock2,
  7. A Greenough1
  1. 1Division of Asthma, Allergy and Lung Biology, Guy’s King’s & St Thomas’ Medical School, King’s College London, UK
  2. 2School of Health Sciences, Brunel University, London, UK
  3. 3Department of Child Health, St George’s Hospital Medical School, London, UK
  4. 4Department of Child Health, University Hospital, Nottingham, UK
  1. Correspondence to:
    Professor Greenough
    Department of Child Health, 4th Floor Golden Jubilee Wing, King’s College Hospital, London SE5 9RS, UK; anne.greenough{at}


Objective: To test the hypothesis that male compared with female prematurely born infants would have worse lung function at follow up.

Design: Prospective follow up study.

Setting: Tertiary neonatal intensive care units

Patients: Seventy six infants, mean (SD) gestational age 26.4 (1.5) weeks, from the United Kingdom oscillation study.

Interventions: Lung function measurements at a corrected age of 1 year.

Main outcome measures: Airways resistance (Raw) and functional residual capacity (FRCpleth) measured by whole body plethysmography, specific conductance (sGaw) calculated from Raw and FRCpleth, and FRC measured by a helium gas dilution technique (FRCHe).

Results: The 42 male infants differed significantly from the 34 female infants in having a lower birth weight for gestation, requiring more days of ventilation, and a greater proportion being oxygen dependent at 36 weeks postmenstrual age and discharge. Furthermore, mean Raw and FRCpleth were significantly higher and mean sGaw significantly lower. After adjustment for birth and current size differences, the sex differences in FRCpleth and sGaw were 15% and 26% respectively and remained significant.

Conclusion: Lung function at follow up of prematurely born infants is influenced by sex.

  • FRCHe, functional residual capacity assessed using a helium gas dilution technique
  • FRCpleth, functional residual capacity measured by whole body plethysmography
  • Pao, pressure at the airway opening
  • PMA, postmenstrual age
  • Raw, airways resistance
  • sGaw, specific conductance
  • prematurity
  • lung function
  • sex
  • plethysmography

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.


  • Published Online First 17 January 2006

  • Competing interests: none declared