The design of the triple–blinded controlled trial
The design of the triple–blinded controlled trial is shown in Fig. The data collector interviewed mothers using Research Electronic Data Capture (REDCap) and each mother was given a unique identifying number.RegistrationThe data collector team downloaded and installed the app and then launched the app for the first time to subscribe to push notifications with firebase cloud messaging or apple push notification service.The app registered the device to firebase cloud messaging or the apple push notification service.The firebase cloud messaging or apple push notification service accepted the app and sent it to the app as a device token.The data collection team updated the mother’s profile including the mother’s name, identifying number, phone number, and the desired date of the week’s notifications.The app sent the mother’s profile including the device token to the Webapp (the app was now waiting for activation of the version).RandomizationThe administrator used information from REDCap (mother age, educational level, and parity) for randomizing the mother into either the control or intervention group. He then updated the mother’s group in their profile on Webapp to assign them either a control or intervention version.The administrator sent an alert to the mother to open the app for activation.The Webapp sent the notification to the mother app via firebase cloud messaging or apple push notification service based on the device token.The firebase cloud messaging or apple push notification service sent the notification to the mother app based on the device token.ActivationMother touched or opened the notification to activate the app without notice of the app’s version.The app requested the mother’s group from Webapp to create the scheduled local notifications and finished the app registration and activation.Architecture diagramsOnly the administrator could extract information from REDCap and Webapp. In the follow-up phone call, the admin provided data collectors with name, identity number, phone number, and expected birthdate which were extracted from the Webapp. Data analysts would be provided with a data set without information on the control/intervention group.