Table 1

Number, length and timing of messages for each study arm

Message typeNumber of messagesLengthTiming
Push messages82 (both arms)Up to 160 characters (1 SMS ‘screen’)*Three per week (Monday, Wednesday and Saturday mornings) during months 1, 3, 5, 7, 9, 11, 13
Interview reminders and study information (push messages)7 (both arms)160–480 characters (1–3 screens)Months 6, 7, 13
Role model stories (push messages)26 (SRH); 27 (nutrition)
(covering six stories for each arm)
160–640 characters (1–4 screens) per messageTwo per week (sent Monday and Friday mornings) during months 2, 4, 6, 8, 10, 12
‘Alerts’: push messages linking participants to the pull system19 (SRH); 18 (nutrition)160–320 characters (1–2 screens)
Pull (on-demand) messages80 (SRH); 49 (nutrition)160–640 characters (1–4 screens)User determined
  • *Messages are charged per 160 characters (one screen). Messages longer than this will appear as one long SMS on most phones, but may be split into multiple messages on older phones.

  • †There are 13 blocks of 4 weeks each, making up 12 calendar months in total.

  • SMS, short messaging service; SRH, sexual and reproductive health.