Western Norway follow-up

Conducted in 2017-2018

Includes those who were born extremely prematurely in Western Norway in:

PEP 1982 - 1985    at approximately 35 years of age

PEP 1991 - 1992    at approximately 27 years of age

PEP 1999 - 2000    at approximately 27 years of age


Pregnancy normally lasts for 40 weeks. If birth occurs before week 28 or the baby weighs less than 100 grams, this counts as extreme prematurely. Before the 1980’s there were very few of the extremely prematurely born who grew up. However, better medicine, equipment and resources have changed this completely. Almost everyone survives today (1,2).


Survival requires comprehensive and long lasting intensive medical effort, most often by the use of respirator as breathing aid, artificial nutrition given intravenously and a variety of different medications and technical aids. These babies are very small and vulnerable, and it is important to understand the long term consequences of this. 


We know a lot about the development leading up to and including adolescence. But because so few of the prematurely born survived before the 1980’s, we know little about what will happen in adult life. To learn more about this, we are conducting follow-ups through many decades. These studies enable us to give the right intensive medical care for today’s premature babies, and to research whether there is a need of special help or facilitation in later years - until adulthood. 


The consequences of being prematurely born has been an important field of research for the Children and Youth Clinic in Bergen for many decades. Project Extreme Prematurity (PEP) has been following up groups of premature children since the early 1980’s. We are currently following four of these cohorts; those born in early 1980’s, 1990’s and since 2010 until now. In addition to this, Haukeland University Hospital has the responsibility of a group of extremely premature children born in 1999-2000. 


All these cohorts have gone through several important medical examinations, and responded to comprehensive surveys. The knowledge this has given us affects the world’s understanding of the long-term consequences of infant intensive medicine and how premature children develop later in life (3-19). High attendance in the studies has been crucial to gain data integrity and to avoid outliers to have a too high effect on the all-over result.


We are now planning a new examination of the premature birth-cohorts, where the oldest ones will be in their mid-thirties. The world has almost no knowledge about what we are researching. Our area of interest is how the lungs and physical activity has developed in the extremely prematurely borns. In addition to this, we have made a survey that will map conditions concerning quality of life, education and work, family relations and possibly physical ailments or challenges.


Lung function and physical capacity develops from childhood until it peaks by the age 20-30. Then, they both slowly decrease as we get older (20,21). Whether we lose a significant amount of these functions or if they keep a good quality depends on three things; from which top level the quality starts to decrease, at what age it starts and how much the annual loss is. We hope to find the answer to all of this through our research.



  1. Markestad, T. et al. Early death, morbidity, and need of treatment among extremely premature infants. Pediatrics 115, 1289-1298 (2005).

  2. Halvorsen, T., Clemm, H. H. & Vollsaeter, M. Langtidskonsekvenser av prematur fødsel. Lungehelse og fysisk arbeidskapasitet. Allergi i Praksis, 10-18 (2015).

  3. Clemm, H. H., Engeseth, M., Vollsaeter, M., Kotecha, S. & Halvorsen, T. Bronchial hyper-responsiveness after preterm birth. Paediatric respiratory reviews, doi:10.1016/j.prrv.2017.06.010 (2017).

  4. Vollsaeter, M. et al. Adult respiratory outcomes of extreme preterm birth. A regional cohort study. Annals of the American Thoracic Society 12, 313-322, doi:10.1513/AnnalsATS.201406-285OC (2015).

  5. Vollsaeter, M. et al. Children Born Preterm at the Turn of the Millennium Had Better Lung Function Than Children Born Similarly Preterm in the Early 1990s. PloS one 10, e0144243, doi:10.1371/journal.pone.0144243 (2015).

  6. Clemm, H. H., Vollsaeter, M., Roksund, O. D., Markestad, T. & Halvorsen, T. Adolescents who were born extremely preterm demonstrate modest decreases in exercise capacity. Acta paediatrica (Oslo, Norway : 1992) 104, 1174-1181, doi:10.1111/apa.13080 (2015).

  7. Clemm, H. H. et al. Exercise capacity after extremely preterm birth. Development from adolescence to adulthood. Ann.Am.Thorac.Soc. 11, 537-545 (2014).

  8. Vollsaeter, M., Roksund, O. D., Eide, G. E., Markestad, T. & Halvorsen, T. Lung function after preterm birth: development from mid-childhood to adulthood. Thorax 68, 767-776 (2013).

  9. Clemm, H. et al. Aerobic capacity and exercise performance in young people born extremely preterm. Pediatrics 129, e97-e105 (2012).

  10. Roksund, O. D. et al. Left Vocal Cord Paralysis After Extreme Preterm Birth, a New Clinical Scenario in Adults. Pediatrics (2010).

  11. Griffiths, S. T. et al. Cerebral magnetic resonance imaging findings in children born extremely preterm, very preterm, and at term. Pediatric neurology 49, 113-118, doi:10.1016/j.pediatrneurol.2013.03.006 (2013).

  12. Fevang, S. K., Hysing, M., Markestad, T. & Sommerfelt, K. Mental Health in Children Born Extremely Preterm Without Severe Neurodevelopmental Disabilities. Pediatrics 137, doi:10.1542/peds.2015-3002 (2016).

  13. Batsvik, B. et al. Health-related quality of life may deteriorate from adolescence to young adulthood after extremely preterm birth. Acta paediatrica (Oslo, Norway : 1992) 104, 948-955, doi:10.1111/apa.13069 (2015).

  14. Vederhus, B. J. et al. Pain tolerance and pain perception in adolescents born extremely preterm. J.Pain 13, 978-987 (2012).

  15. Vederhus, B. J., Markestad, T., Eide, G. E., Graue, M. & Halvorsen, T. Health related quality of life after extremely preterm birth: a matched controlled cohort study. Health Qual.Life Outcomes. 8, 53 (2010).

  16. Haugen, O. H., Nepstad, L., Standal, O. A., Elgen, I. & Markestad, T. Visual function in 6 to 7 year-old children born extremely preterm: a population-based study. Acta ophthalmologica 90, 422-427, doi:10.1111/j.1755-3768.2010.02020.x (2012).

  17. Stangenes, K. M. et al. Children born extremely preterm had different sleeping habits at 11 years of age and more childhood sleep problems than term-born children. Acta paediatrica (Oslo, Norway : 1992), doi:10.1111/apa.13991 (2017).

  18. Leversen, K. T. et al. Prediction of neurodevelopmental and sensory outcome at 5 years in Norwegian children born extremely preterm. Pediatrics 127, e630-e638 (2011).

  19. Griffiths, S. T. et al. fMRI: blood oxygen level-dependent activation during a working memory-selective attention task in children born extremely preterm. Pediatric research 74, 196-205, doi:10.1038/pr.2013.79 (2013).

  20. Sharma, G. & Goodwin, J. Effect of aging on respiratory system physiology and immunology. Clinical interventions in aging 1, 253-260 (2006).

  21. Kerstjens, H. A., Rijcken, B., Schouten, J. P. & Postma, D. S. Decline of FEV1 by age and smoking status: facts, figures, and fallacies. Thorax 52, 820-827 (1997).