Mothers who come from developed nations with a strong Catholic heritage are less likely to breastfeed, a study suggests.
Experts looked at data from 135 countries on breastfeeding rates and the proportions of Catholics and Protestants.
They also examined regional areas of the UK, France, Ireland, Canada and the USA.
After taking account of factors including population density and gross domestic product, the researchers found a link between religious affiliation and breastfeeding rates in Western countries.
The finding held true even when the researchers looked at breastfeeding initiation rates across different parts of the same country - the higher the proportion of Catholics in regions of France, Ireland, the UK and Canada, the lower breastfeeding rates in those regions.
The authors of the study, which has been published in the journal BMJ Global Health, called for further research to examine their findings, adding: "Studies are also necessary to identify the sociocultural values and beliefs that mediate the relationships between a historically Catholic family or societal background and breast feeding."
If confirmed, their finding could help health officials target their breastfeeding promotional materials according to "socio-cultural background", they added.
"Our results suggest that women living in a country or region where Catholicism has historically dominated are less likely to initiate breastfeeding, and that breastfeeding promotion policies should be adapted to better fit populations' cultural and religious norms," they wrote.