BackgroundThe gestational diabetes causes complications for the mother and the baby.MethodsIt was a randomised controlled trial that was conducted in Public Health Center No 1 in Baghmalek, Khuzestan province, Iran. Seventy-six women with gestational diabetes mellitus (GDM) were recruited and randomly allocated into an intervention (n=38) and a control group (n=38). A mobile app was developed, and the content of the educational programme was designed according to the six dimensions of Health Promotion Lifestyle Profile (HPLP). Participants in the intervention group followed instructions about healthy lifestyle for 4 weeks, whereas the control group received only routine care. A demographic questionnaire, and the HPLP-II were used to gather the data.Health promoting lifestyle and blood sugar of participants were measured after 4 weeks.ResultsThe total score of HPLP was 98.34±13.99 and 92.39±14.56 before the intervention in intervention and control groups, respectively, which was improved significantly in the intervention group compared with the control group after intervention (143.13±23.41 vs 100.39±16.69, p<0.0001). Also, the scores of stress management, responsibility, interpersonal relationship, spiritual growth, nutrition and physical activity were significantly improved in the intervention group. Fasting blood sugar and blood sugar 2 hours after meal significantly reduced in the intervention group compared with the control group (86.05±7.71 mg/dL vs 93.92±5.52 mg/dL) and (113.65±10.96 mg/dL vs 124.97±9.15 mg/dL), (p=0.001), respectively.ConclusionsOur results showed that offering educational programmes based on mobile apps can improve healthy lifestyle and blood sugar in women with GDM.Trial registration numberIRCT20200817048434N1Website addresshttps://www.irct.ir/search/result?query=IRCT20200817048434N1