Is the impact of paid maternity leave policy on the prevalence of childhood diarrhoea mediated by breastfeeding duration? A causal mediation analysis using quasi-experimental evidence from 38 low-income and middle-income countries

Objectives Quasi-experimental evidence suggests that extending the duration of legislated paid maternity leave is associated with lower prevalence of childhood diarrhoea in low-income and middle-income countries (LMICs). This could be due to a variety of mechanisms. This study examines whether this effect is mediated by changes in breastfeeding duration. Design and setting Difference-in-difference approach and causal mediation analysis were used to perform secondary statistical analysis of cross-sectional data from Demographic and Health Surveys (DHSs) in 38 LMICs. Participants We merged longitudinal data on national maternity leave policies with information on childhood diarrhoea related to 639 153 live births between 1996 and 2014 in 38 LMICs that participated in the DHS at least twice between 1995 and 2015. Primary outcome measure Our outcome was whether the child had bloody stools in the 2 weeks prior to the interview. This measure was used as an indicator of severe diarrhoea because the frequency of loose stools in breastfed infants can be difficult to distinguish from pathological diarrhoea based on survey data. Results A 1-month increase in the legislated duration of paid maternity leave was associated with a 34% (risk ratio 0.66, 95% CI 0.47 to 0.91) reduction in the prevalence of bloody diarrhoea. Breast feeding for at least 6 months and 12 months mediated 10.6% and 7.4% of this effect, respectively. Conclusion Extending the duration of paid maternity leave appears to lower diarrhoea prevalence in children under 5 years of age in LMICs. This effect is slightly mediated by changes in breastfeeding duration.