The Effect of a Theory of Planned Behavior-Based Education Model on Self-Management and Metabolic Control in Pregnant Women with Gestational Diabetes: A Randomized Controlled Trial

Background Gestational diabetes is one of the most common complications of pregnancy and is associated with adverse health outcomes. Metabolic control can be achieved through lifestyle behavioral interventions; however, there is ongoing debate on how these interventions should be designed. Aim This study aimed to determine the effect of a personalized Theory of Planned Behavior (TPB)-based online education model on gestational diabetes self-management and metabolic control. Methods This randomized controlled trial was conducted with 66 pregnant women between 24–28 weeks of gestation (intervention: 33, control: 33). Data were collected using the Data Collection Form, the Gestational Diabetes Intention, Attitude, and Behavior Questionnaire (GDIAB-Q), the Metabolic Control Variables Form. While the control group received standard care, the intervention group underwent an online education program based on TPB structured with “Motivational Interviewing” across three modules delivered at the 28th, 29th, and 30th weeks of gestation. The data were analyzed at a significance level of less than 0.05 using the SPSS software (v. 23.0). Results The demographic characteristics of the pregnant women were homogeneous. The intervention group had significantly higher mean scores in the GDIAB-Q sub-dimension of attitude (p < 0.005), subjective norms (p < 0.002), and intention (p < 0.028) compared to the control group. Among the metabolic control variables, postprandial blood glucose (153.3 mg/dl), HbA1c (6.4 mg/dl), and body mass index (28.29 kg/m²) showed lower mean values in the intervention group (p < 0.05), with no significant differences in other parameters (p > 0.05). Conclusion The TPB-based online education model implemented in this study had positive effects on gestational diabetes self-management and key metabolic control parameters. Trial registration This randomized controlled trial was registered at ClinicalTrials.gov (NCT04874922, registration date: 27/11/2021).