Background: More mothers are choosing to return to work during the first 2 years of their child's life with an uncertain impact on early developmental outcomes.
Aims: To determine the association between duration of maternity leave and motor and social development of toddlers.
Study design: Population-based, retrospective cohort study.
Subjects: The Canadian National Longitudinal Survey on Children and Youth (NLSCY) Cycle 3 provides data on the characteristics and life experience of Canadian children. For sampled households, the person most knowledgeable about the child completed a survey on demographics, parent characteristics and family environment. The analysis was limited to 6664 families with children up to 2 years.
Outcome measures: Logistic regression was used to assess the association between duration of maternity leave and impaired performance (<-1 SD below the mean) on the Motor and Social Development (MSD) scale adjusted for multiple covariates including maternal age, gender, breastfeeding and socioeconomic status.
Results: One month of maternity leave increased the odds of impaired performance on the MSD by 3% (OR 1.03, 95% CI 1.02, 1.04). This was also seen with categorized maternity leave duration. Being male (OR 1.53, 95% CI 1.35, 1.74) and having a younger mother (OR 1.48, 95% CI 0.98, 2.23) increased the risk of impaired performance on the MSD while being of higher SES reduced the risk (OR 0.96, 95% CI 0.93, 1.00).
Conclusions: There is an association between duration of maternity leave and impaired performance in motor and social development in children up to 2 years.