Effects of Cognitive Behavioral Therapy for Diet on Postprandial Glucose and Pregnancy Outcomes in Gestational Diabetes Mellitus: A multicenter randomized controlled trial (Preprint)

Abstract Background Gestational diabetes mellitus (GDM) is associated with an elevated risk of adverse maternal and neonatal outcomes. Dietary management is a cornerstone of GDM treatment due to its beneficial effects on metabolic control. However, suboptimal adherence to dietary recommendations has diminished its potential benefits in achieving optimal glycemic outcomes. Cognitive behavioral therapy (CBT)–based interventions have emerged as a promising approach to enhance dietary compliance and glycemic control in patients with GDM. Objective This study aims to investigate the effects of a CBT-based digital dietary intervention on glycemic control and pregnancy outcomes in patients with GDM. Methods The intervention group received standard care plus a digital dietary intervention based on CBT principles, delivered via a customized WeChat (Tencent Inc) mini program. This intervention included structured dietary education and behavioral strategies focused on appropriate food selection and meal sequencing. The control group received standard care alone. The primary outcome was the glycemic qualification rate, and secondary outcomes included fasting blood glucose, postprandial blood glucose (PBG), General Self-Efficacy Scale scores, and incidence of macrosomia. Self-monitored blood glucose data were collected and analyzed at biweekly follow-up visits from enrollment until delivery. Results Of the 200 participants, 171 completed the study. The average age was 31.2 (SD 4) years, and the average gestational age at enrollment was 26.3 (SD 1.6) weeks. Baseline HbA 1c levels were similar between groups (5.2% vs 5.1%; P=. 97). The glycemic qualification rate was significantly higher in the intervention group than in the control group at follow-up 3 (mean 87.9%, SD 14.9% vs 81.9%, SD 17.8%; P =.02), follow-up 4 (mean 91.0%, SD 9.9% vs 87.2%, SD 14.4 %; P =.04), follow-up 5 (mean 94.0%, SD 7.4% vs 91.5%, SD 9.5%; P =.04), and follow-up 6 (mean 94.3%, SD 6.7% vs 91.8%, SD 8.9%). PBG levels were significantly lower in the intervention group after lunch (1 h: mean 5.9, SD 0.7 vs 6.0, SD 0.7 mmol/L; P =.0 2 h2h: 5.1, SD 0.7 vs 5.3, SD 0.8 mmol/L; P =.03) and dinner (1 h: mean 6.0, SD 0.5 vs 6.2, SD 0.6; 2 h: 5.5, SD 0.7 vs 5.7, SD 0.8 mmol/L). However, no significant differences were observed in fasting blood glucose or PBG after breakfast between the groups. The intervention group showed significantly higher General Self-Efficacy Scale scores than the control group (mean 195.4, SD 6.9 vs 192.9, SD 5.8). The incidence of macrosomia was significantly lower in the intervention group than in the control group (5% vs 15%; P =.04). Conclusions The findings of this randomized controlled trial suggest that a CBT-based digital dietary intervention can significantly enhance glycemic control, particularly PBG levels, and may contribute to improved pregnancy outcomes with a reduced incidence of macrosomia in women with GDM.