Article Text

Original research
Interpregnancy intervals and child development at age 5: a population data linkage study
  1. Gursimran Kaur Dhamrait1,2,
  2. Catherine Louise Taylor1,3,
  3. Gavin Pereira1,4,5
  1. 1Telethon Kids Institute, University of Western Australia, Perth, Western Australia, Australia
  2. 2School of Population and Global Health, University of Western Australia, Perth, Western Australia, Australia
  3. 3Centre for Child Health Research, University of Western Australia, Perth, Western Australia, Australia
  4. 4Curtin School of Population Health, Curtin University, Perth, Western Australia, Australia
  5. 5Centre for Fertility and Health (CeFH), Norwegian Institute of Public Health, Oslo, Norway
  1. Correspondence to Gursimran Kaur Dhamrait; gursimran.dhamrait{at}


Objective To investigate the associations between interpregnancy intervals (IPIs) and developmental vulnerability in children’s first year of full-time school (age 5).

Design Retrospective cohort study using logistic regression. ORs were estimated for associations with IPIs with adjustment for child, parent and community sociodemographic variables.

Setting Western Australia (WA), 2002–2015.

Participants 34 574 WA born singletons with a 2009, 2012 or 2015 Australian Early Development Census (AEDC) record.

Main outcome measure The AEDC measures child development across five domains; Physical Health and Wellbeing, Social Competence, Emotional Maturity, Language and Cognitive Skills (school-based) and Communication Skills and General Knowledge. Children with scores <10th percentile were classified as developmentally vulnerable on, one or more domains (DV1), or two or more domains (DV2).

Results 22.8% and 11.5% of children were classified as DV1 and DV2, respectively. In the adjusted models (relative to the reference category, IPIs of 18–23 months), IPIs of <6 months were associated with an increased risk of children being classified as DV1 (adjusted OR (aOR) 1.17, 95% CI 1.08 to 1.34), DV2 (aOR 1.31, 95% CI 1.10 to 1.54) and an increased risk of developmental vulnerability for the domains of Physical Health and Wellbeing (aOR 1.25, 95% CI 1.06 to 1.48) and Emotional Maturity (aOR 1.36, 95% CI 1.12 to 1.66). All IPIs longer than the reference category were associated with and increased risk of children being classified as DV1 and DV2 (aOR >1.15). IPIs of 60–119 months and ≥120 months, were associated with an increased risk of developmental vulnerability on each of the five AEDC domains, with greater odds for each domain for the longer IPI category.

Conclusions IPIs showed independent J-shaped relationships with developmental vulnerability, with short (<6 months) and longer (≥24 months) associated with increased risks of developmental vulnerability.

  • community child health
  • public health
  • epidemiology

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  • Contributors GKD led study conceptualisation and design, conducted the literature review, performed data manipulation, analysis and interpretation of findings, drafted the initial manuscript and reviewed and revised the manuscript critically for important intellectual content. GP and CLT contributed to conceptualising and designing the study, interpreting the results and writing the manuscript. All authors approved the final manuscript as submitted and agree to be accountable for all aspects of the work.

  • Funding This work was supported by the National Health and Medical Research Grants (grant numbers GNT1173991 and GNT1099655 to GP), the Australian Research Council Centre of Excellence for Children and Families over the Life Course (grant number CE140100027 to CLT). GKD was supported by the ARC Centre of Excellence for Children and Families over the Life Course Scholarship, the ARC Centre of Excellence for Children and Families over the Life Course Top-Up Scholarship and the Stan and Jean Perron Top-Up Scholarship. GP was supported with funding from the National Health and Medical Research Council Project and Investigator (grant numbers 1099655 and 1173991) and the Research Council of Norway through its Centres of Excellence funding scheme (grant number 262700).

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Ethics approval Ethics approval for this study was granted by the Western Australian Department of Health Human Research Ethics Committee (2016/51) and the University of Western Australia Human Research Ethics Committee (RA/4/20/4776).

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement All data relevant to the study are included in the article or uploaded as supplementary information. We received data from WA Department of Health through the Data Linkage Branch. The data are not publicly available, and privacy and legal restrictions apply to the provision of the data to third parties.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.