Funding for this research was provided by:
Chiang Mai University (CMU-2562)
Text and Data Mining valid from 2019-04-11
Received: 5 December 2018
Accepted: 27 March 2019
First Online: 11 April 2019
Ethics approval and consent to participate
: This study was approved by the Institutional Review Boards; The Research Ethics Committee 4; Faculty of Medicine, Chiang Mai University. Study code: OBG-2560-04899/ Research ID: 4899.All participants were recruited with written informed consent.
: The Informed Consent Forms which all participants signed included consent for publication of their data. Data were de-identified after collection and participants were allocated codes for analysis and pseudonyms for publication.
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.