Table 3.

The preliminary intervention protocol

Primary indicators(theory components)	Secondary indicators	Tertiary indicators	Time	Delivery type	Duration	Intervener
1. Accomplishment experiences	1.1 knowledge education session	1.1.1 What is GDM? 1.1.2 Adverse health outcomes of GDM? 1.1.3 Physical activity could prevent GDM. 1.1.4 The frequence, intensity,type, time of physical activity during pregnancy	13–14+ 6 weeks’ gestation	face to face in groups with 15–20 participants	about 40 min	Researcher, nurse and midwife
	1.2 exercise clinic visit	1.2.1 the coach teach pregnant women how to exercise safely 1.2.2 the coach guide the participants to do physical activity together following the exercise video. 1.2.3 uploaded the exercise video to WeChat platform 1.2.4 teach the participants how to keep exercise diary	13–14+ 6 weeks’ gestation	face to face in groups with 15–20 participants	about 50 min	Researcher, coach, obstetricians, nurses, and midwife
2. Vicarious experience	2.1 positive feedback	2.1.1 Checking behavioral tracking, review, and feedback on goals	every two weeks from 15–16+ 6 to 37 weeks	online group discussion with 15–20 participants via Tencent Meeting	about 15–20 min	Researcher, nurse and midwife
	2.2 role model	2.2.1 Sharing self-management strategies from successful pregnant women
3.Verbal persuasion	3.1 reminder	3.1.1 Daily reminders via the WeChat group to encourage the women to follow the 40-min video, performing the exercises and recording in their exercise diary	every two weeks from 15–16+ 6 to 37 weeks	online group discussion with 15–20 participants via Tencent Meeting	about 15–20 min	Researcher, nurse and midwife
	3.2 problem solving	3.2.1 Discuss the problems that arise when doing exercise and share solutions on how to keep active with each other
	3.3 encourage	3.3.1 Confrming participants have the capability for exercise and weight self-management
	3.4 recall previous successful experience	3.4.1 Guiding participants to recall previous successful behavior-change situations, discuss context and factors associated with success
	3.5 positive feedback	3.5.1 Providing positive feedback for the participant’s effort
4. physiological and emotional status	4.1 knowledge education session	4.1.1 Assessing and explaining the participant’s pregnancy-related symptoms, and discussing strategies for managing symptoms, such as muscle relaxation	15–16+ 6 weeks’ gestation	online group discussion with 15–20 participants via Tencent Meeting	about 30 min	Researcher, nurse, and midwife
		4.1.2 Assessing and explaining the participant’s negative emotions, and discussing strategies for managing anxiety, or depression, such as positive self-talk	17–18+ 6 weeks’ gestation	online group discussion with 15–20 participants via Tencent Meeting	about 30 min	Researcher, nurse, midwife, and psychological consultant

Note: GDM, gestational diabetes mellitus