Online survey on app features and contents
We sent an online survey link through a Facebook page to the contacts of a young researcher aged in her 30s, who was likely to have contact with the infant’s mothers. A total of 49 mothers and fathers responded to the survey. A questionnaire included information on the characteristics of respondents, time for installing the app, desires for app functions, information on maternal and child health care, and breastfeeding. The preferences for information on maternal and child health care were scored from 1 to 3, in which, 1 was the lowest and 3 was the highest. Data were collected using the Qualtrics system (Qualtrics, Provo, UT).