The current study aimed to assess trends, associated factors and the changes in these factors for exclusive breast-feeding (EBF) over the past two decades in Lao People’s Democratic Republic (Lao PDR).

The current study used a quasi-longitudinal design. Descriptive analyses were done with correction for complex survey design. Inferential analyses were done for survey years separately using multiple logistic regression. Finally, pooled logistic regression analysis was done using interaction terms to quantify the difference in association per year.

The current study used data from all provinces of Lao PDR collected in the years 2000, 2006, 2011/2012 and 2017.

Children aged six months or younger from Lao PDR.

EBF practice was estimated at 19·03 %, 26·87 %, 40·67 % and 44·89 % in the four survey years, respectively. Factors significantly associated with EBF included: region of residence, ethnicity, wealth index and age of child. Region and ethnicity saw significant changes in association, and the South developing positively over time as well as in the Lao-Thai ethnic group. Having had any antenatal visits was not associated with EBF practice, nor did this change over time.

Our study shows how EBF trends, and factors associated with EBF, changed over time. We applied an easily replicable methodology to assess similar public health phenomena. We argue that such analysis is particularly relevant for transitioning countries. In such rapidly evolving settings, it is crucial to take into account changing underlying factors when assessing and developing public health policy.