Funding for this research was provided by:
Chiang Mai University
Health Systems Research Institute
Received: 14 July 2020
Accepted: 22 March 2021
First Online: 14 April 2021
: The study was approved on the 2nd June 2009 by the Research Ethics Committee 3 at the Faculty of Medicine, Chiang Mai University (approval #177/2009). All participants (mothers and offspring) provided written informed consent. All procedures in this study were conducted according to the ethical principles and guidelines laid down in the Declaration of Helsinki [CitationRef removed].
: Not applicable.
: The authors have no financial or non-financial conflicts of interest to declare in association with this work.