Association between maternal shift work and infant neurodevelopmental outcomes: results from the Taiwan Birth Cohort Study with propensity-score-matching analysis

Int J Epidemiol. 2019 Oct 1;48(5):1545-1555. doi: 10.1093/ije/dyz045.


Background: Maternal shift work is associated with preterm delivery, small-for-gestational-age new-borns, childhood obesity and future behavioural problems. However, the adverse effects on and interactions of maternal shift work with infant neurodevelopment remain uncertain. Therefore, we examined the associations between maternal-shift-work status and infant neurodevelopmental parameters.

Methods: The Taiwan Birth Cohort Study is a nationwide birth cohort study following representatively sampled mother-infant pairs in 2005. The participants' development and exposure conditions were assessed by home interviews with structured questionnaires at 6 and 18 months of age. Propensity scores were calculated with predefined covariates for 1:1 matching. Multivariate conditional logistic regression and the Cox proportional-hazards model were used to examine the association between maternal-shift-work status and infant neurodevelopmental-milestone-achievement status.

Results: In this study, 5637 term singletons were included, with 2098 cases selected in the propensity-score-matched subpopulation. Persistent maternal shift work was associated with increased risks of delays in gross-motor neurodevelopmental milestones [aOR = 1.36, 95% confidence interval (CI) = 1.06-1.76 for walking steadily], fine-motor neurodevelopmental milestones (aOR = 1.39, 95% CI = 1.07-1.80 for scribbling) and social neurodevelopmental milestones (aOR = 1.35, 95% CI = 1.03-1.76 for coming when called upon). Moreover, delayed gross-motor and social development were identified in the propensity-score-matched sub-cohort.

Conclusions: This study shows negative associations between maternal shift work and delayed neurodevelopmental-milestone achievement in the gross-motor, fine-motor and social domains at 18 months. Future research is necessary to elucidate the possible underlying mechanisms and long-term health effects.

Keywords: Shift work; birth cohort; neurodevelopment; propensity-score matching.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Child Development*
  • Female
  • Humans
  • Infant
  • Infant, Newborn
  • Logistic Models
  • Male
  • Motor Skills*
  • Multivariate Analysis
  • Pregnancy
  • Prenatal Exposure Delayed Effects
  • Propensity Score
  • Proportional Hazards Models
  • Prospective Studies
  • Shift Work Schedule / adverse effects*
  • Taiwan
  • Young Adult