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NZ Very Low Birthweight Study

Mapping The Road Ahead


The NZ VLBW study is looking at health and developmental outcomes in young adulthood for New Zealand children born in 1986 who were born very early (premature) and with very low birthweight (less than 1,500 grams).

Since the 1980s, changes in medical technology have resulted in dramatic improvements in the survival of children born very early or very small. However, there have been ongoing concerns that premature infants have increased risks of some health problems and higher rates of disability and developmental problems than other children.

Currently, around the world there is considerable interest in the long term outcomes for these infants, as substantial numbers of premature and low birthweight infants are now growing into adulthood.

Current project

The purpose of this study is to obtain information on the long term outcomes of prematurity or very low birthweight for New Zealand children. We are comparing health, developmental and life course outcomes at age 26/27 years for two groups of young adults:

  • VLBW Participants – survivors of the group of children born in New Zealand in 1986 and weighing less than 1,500 grams at birth
  • Controls – a comparison series of young adults who were born in New Zealand in 1986 but who were healthy at birth and not born premature or of very low birthweight


  • There are just over 300 survivors from a total of 413 children who were born in New Zealand in 1986 weighing less than 1,500 grams at birth
  • At 7–8 years, with parents’ permission, these children were involved in a study looking at developmental outcomes for very low birthweight infants
  • At 23–24 years, they participated in an interview looking at each individual's circumstances and life experiences
  • At 27–29 years they came to Christchurch for a comprehensive assessment over two days covering physical and mental health and cognitive, neuropsychological and social functioning


  • The control group took first part in the study at 22-23 years of age when they completed the same interview as VLBW participants. Most of the control group had been nominated by a VLBW participant, although a few were identified from the electoral roll as possible candidates for enrolment in the study
  • At 27-29 years controls were assessed in Christchurch in the same way as VLBW participants


Darlow BA, Horwood LJ, Pere-Bracken H, Woodward LJ. Psychosocial outcomes of young adults born very low birth weight. Pediatrics, 2013; 132: e1521-1528. doi: 10.1542/peds.2013-2024

Darlow BA, Horwood LJ, Woodward LJ, Elliott JM, Troughton RW, Elder M, Epton M, Stanton J, Swanney M, Keenan R, Melzer T, McKelvey V, Levin K, Meeks MG, Espiner EA, Cameron VA, Martin J. The New Zealand 1986 very low birth weight cohort as young adults: mapping the road ahead. Study protocol. BMC Pediatrics, 2015; 15: 90. doi: 10.1186/s12887-015-0413-9

Darlow BA, Elder M, Kimber B, Martin J, Horwood LJ. Vision in former very low birthweight young adults with and without retinopathy of prematurity compared with term born controls: The NZ 1986 VLBW Follow-up Study. British Journal of Ophthalmology, 2018; 102: 1041-6. doi: 10.1136/bjophthalmol-2017-311345

Darlow BA, Martin J, Horwood LJ. Metabolic syndrome in very low birth weight young adults and controls: the NZ 1986 VLBW study. Journal of Pediatrics, 2019; 206: 128-133.e5. doi: 10.1016/j.jpeds.2018.10.060.

Darlow BA, Martin J, Horwood LJ. Unrecognised and unmet physical health problems in a national cohort of very low birthweight (VLBW) young adults and controls. J Primary Health Care, 2019; 11: 32-8. doi: 10.1071/HC18044

Pascoe MJ, Melzer TR, Horwood LJ, Woodward LJ, Darlow BA. Altered grey matter volume, perfusion and white matter integrity in very low birthweight adults. NeuroImage: Clinical, 2019; 22 :101780. doi: 10.1016/j.nicl.2019.101780

Prickett, T. C. R., Darlow, B. A., Troughton, R. W., Cameron, V. A., Elliott, J. M., Martin, J., Horwood, L. J., & Espiner, E. A. (2017). New insights into cardiac and vascular natriuretic peptides: Findings from young adults born with very low birth weight. Clinical Chemistry, 64(2).   doi: 10.1373/clinchem.2017.280354

Please email us if you require a copy of the above papers:

For further information, please contact

Bridget Kinnersley (Research Administrator)
Department of Psychological Medicine, University of Otago, Christchurch
PO Box 4345, Christchurch 8140, New Zealand
Tel +64 3 372 6706

Physical Address:
Level 3, Terrace House, 4 Oxford Terrace, Christchurch, New Zealand


Professor Brian Darlow
Department of Paediatrics, University of Otago, Christchurch 
PO Box 4345, Christchurch 8140, New Zealand 

Tel +64 3 372 6735