Here is the design of a clinical trial:

Official Title: eHealth in Treatment of Gestational Diabetes - eMOM GDM -Study (Phase 2)

Included conditions:
- Gestational Diabetes
- Mobile Application

Study Armgroups:
- {'label': 'Intervention (eMOM GDM application)', 'type': 'EXPERIMENTAL', 'description': 'Participants in the intervention group will use the eMOM GDM -application one week/month. The participants will also receive regular antenatal care in maternity clinics and hospitals. In addition they will meet a study nurse three times during study period (at GW 24-28, at GW 35-37 and 3 mo postpartum).', 'interventionNames': ['Device: eMOM GDM application']}
- {'label': 'Control', 'type': 'NO_INTERVENTION', 'description': 'Participants in the control group will meet a study nurse 3 times during study period (at GW 24-28, at GW 35-37 and 3 mo postpartum). They also receive regular antenatal care in maternity clinics and hospitals.'}

Interventions:
- {'type': 'DEVICE', 'name': 'eMOM GDM application', 'description': 'Participants in the intervention group will use the eMOM GDM -application one week/month.\n\neMOM GDM application includes:\n\n* continuous glucose monitor (CGM, Medtronic)\n* diet (digital food tracker) (min 3 days during one application week)\n* heartrate, stress and physical activity with the wrist-worn activity tracker (Vivosmart 3)\n* weight measured once a week\n\nThe sensors can be worn and the application used during the whole pregnancy (if a mother is interested in)', 'armGroupLabels': ['Intervention (eMOM GDM application)']}

Primary Outcomes:
- {'measure': 'Change in fasting glucose', 'description': 'change in fasting glucose measured by Huslab (laboratory measurement)', 'timeFrame': 'from gestational weeks 24-28 to gestational weeks 35-37'}

Please estimate the sample size based on the assumption: 
Significance level (α) < 0.05, power = 95%, assumed drop-out rate = 40%.
Sample size
        To detect at least a 0.32âmmol/L between-group mean difference in the fP-glucose (primary outcome) response to the intervention (Î±<0.05, power=95%, an assumed drop-out rate of 40%), a sample of 200âwomen (100 in each intervention arm) is needed for the intervention study. This anticipated difference of 0.32âmmol/L between the intervention group and control group corresponds to 0.7 SD of variation in fP-glucose change observed previously in similar women and stage of pregnancy (SD needed for power calculation has been calculated from the Finnish Gestational Diabetes Prevention Study-population; SD for change in fP-glucose value between II and III trimesters in women who got GDM diagnoses at II trimester).51