Abstract
BACKGROUND: The key to gestational weight management intervention involves health-related behaviors, including dietary and exercise management. Behavioral theory-based interventions are effective in improving health-related behaviors. However, evidence for mobile health interventions based on specific behavioral theories is insufficient and their effects have not been fully elucidated. OBJECTIVE: This study aimed to examine the effects of a gestational mobile health intervention on psychological cognition and behavior for gestational weight management, using an integrated behavioral model as the theoretical framework. METHODS: This study was conducted in a tertiary maternity hospital and conducted as a single-blind randomized controlled trial (RCT) in Changzhou, Jiangsu Province, China. Using the behavioral model, integrated with the protection motivation theory and information-motivation-behavioral skills model (PMT-IMB model), the intervention group received a mobile health intervention using a self-developed app from 14 to 37 gestational weeks, whereas the control group received routine guidance through the application. Psychological cognition and behaviors related to weight management during pregnancy were the main outcomes, which were measured at baseline, and at the second and third trimesters of pregnancy using a self-designed questionnaire. Generalized estimation and regression equations were used to compare the outcome differences between the intervention and control groups. RESULTS: In total, 302 (302/360, 83.9%) participants underwent all measurements at 3 time points (intervention group: n=150; control group: n=152). Compared with the control group, the intervention group had significantly higher scores for information, perceived vulnerability, response cost, and exercise management in the second trimester, while their scores for perceived vulnerability, response cost, and diet management were significantly higher in the third trimester. The results of repeated measures analysis revealed that, in psychological cognition, the information dimension exhibited both the time effects (T3 β=3.235, 95% CI 2.859-3.611; P<.001) and the group effects (β=0.597, 95% CI 0.035-1.158; P=.04). Similarly, response costs demonstrated both the time effects (T3 β=0.745, 95% CI 0.199-1.291; P=.008) and the group effects (β=1.034, 95% CI 0.367-1.700; P=.002). In contrast, perceived vulnerability solely exhibited the group effects (β=0.669, 95% CI 0.050-1.288; P=.03). Regarding weight management behaviors, both time (T3 β=6, 95% CI 4.527-7.473; P<.001) and group (β=2.685, 95% CI 0.323-5.047; P=.03) had statistically significant impacts on the total points. Furthermore, the exercise management dimension also demonstrated both the time effects (T3 β=3.791, 95% CI 2.999-4.584; P<.001) and the group effects (β=1.501, 95% CI 0.232-2.771; P=.02). CONCLUSIONS: The intervention program was effective in increasing psychological cognitions in terms of information, perceived vulnerability, and response costs, as well as promoting healthy behaviors among Chinese pregnant women. This study provides new evidence supporting the effectiveness of mobile intervention based on behavioral science theory in gestational weight management. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR2100043231; https://www.chictr.org.cn/showproj.html?proj=121736.