Introduction

Gestational diabetes mellitus (GDM) is one of the most common pregnancy complications and health problems, which poses long‐term and short‐term threats to maternal and fetal morbidity.1 One of the most significant risk factors for GDM is having a history of GDM.2 Additional risk factors include obesity, being 35 years or older, and a family history of type 2 diabetes.3 The prevalence of GDM was 15.8% globally in 2021, with an increasing trend over time. In China, the prevalence of GDM was 14.8%.4 With the “two‐child policy” in 2016 and the “three‐child policy” in 2021 in mainland China, the proportion of pregnant women 35 years or older with pre‐pregnancy overweight or obese status increased dramatically.5 Consequently, the incidence of GDM will likely increase. There is a high priority to take strategies to prevent the occurrence of GDM, especially among pregnant women at high risk for GDM in mainland China.6

Physical activity is “any bodily movement produced by skeletal muscles that results in energy expenditure”.7 Physical activity increases glucose uptake in the skeletal muscle.8 It has immediate and longer-term effects on insulin sensitivity.8 The WHO and multiple national guidelines recommend that pregnant women without contraindications should engage in at least 150 minutes of moderate-intensity activity weekly.9 Evidence indicates that physical activity could decrease the odds of developing GDM,10–12 in particular for pregnant women at high risk for GDM.13 However, a recent systematic review indicated that most pregnant women in the world do not meet the current physical activity guidelines.14 It is reported that about half of pregnant women in mainland China do not reach the recommended physical activity levels.15 Furthermore, pregnant women at high risk for GDM spent most of their time in sedentary behaviors despite a low prevalence of contraindications to be physically active.16

Physical activity self-efficacy has been identified as a significant predictor of physical activity, which healthcare professionals can amend.17,18 According to Bandura,19,20 self-efficacy is “the belief in one’s capabilities to organize and execute the courses of action required in managing prospective situations”. Physical activity self-efficacy refers to confidence in one’s ability to persist with physical activity in various situations.21 Physical activity self-efficacy is a modifiable theoretical factor related to pregnant women’s physical activity.22,23 Pregnant women with a higher level of physical activity self-efficacy demonstrated more stability and increased physical activity behavior during pregnancy.24

Physical activity self-efficacy may be related to many factors. Firstly, according to Bandura,19,20 self-efficacy is influenced by individual direct successful experience, vicarious experiences through observing others doing an assignment successfully, verbal persuasion through gaining positive feedback about completing an assignment, and emotional arousal through adjusting their physiological and psychological status. Previous studies in the non-pregnant and general pregnant population revealed that physical activity self-efficacy was positively related to social support,25–27 knowledge of physical activity,28 intention to do physical activity29 and negatively related to anxiety and depressive symptoms.30

Previous studies on general pregnant women also showed that physical activity self-efficacy was related to their husband’s habit of regular physical activity,31 and environment being appropriate to do physical activity,32 demographic characteristics including age,33 pre-pregnancy body mass index (BMI),31 perinatal characteristics including gestational age,26,27,33 mode of conception,31 and attendance in antenatal classes.27 The physical activity self-efficacy in pregnant women at high risk for GDM may also be related to culture. In Chinese tradition, rest and recuperation are strongly encouraged once a woman is pregnant.34 The traditional beliefs and practices related to pregnancy are still popular among many current Chinese women.35

Pregnancy is a “teachable moment” during which women are amenable to changing their behaviors to benefit themselves and their baby’s health.36 Physical activity self-efficacy can serve as an indicator for pregnant women at high risk for GDM who require additional intervention to enhance their physical activity.23 Healthcare professionals need to understand, recognize, and address physical activity self-efficacy and its predictors in pregnant women at high risk for GDM. However, to our knowledge, no study has examined the predictors of physical activity self-efficacy in pregnant women at high risk for GDM in mainland China. Therefore, this study aimed to examine physical activity self-efficacy and identify its predictors in pregnant women at high risk for GDM.

Based on the self-efficacy theory and the literature, we postulated the following assumption: (1) Pregnant women at high risk for GDM had a moderate level of physical activity self-efficacy. (2) Knowledge of physical activity, social support for physical activity, intention to do physical activity, and emotion were predictors for physical activity self-efficacy.

Methods Study Design, Setting, and Participants

This was a cross-sectional study that examined physical activity and physical activity self-efficacy among Chinese pregnant women at high risk for GDM. The paper about physical activity and its predictors was published elsewhere.37 This paper focused on physical activity self-efficacy and its predictors. This study was conducted and reported following the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist (Supplementary File 1).

This study was conducted in Zhengzhou, China, between October 2021 and February 2022. Zhengzhou is a sub-provincial city located in the central plains of China. It is the capital of Henan Province and has approximately 13 million people. The participants were recruited from the antenatal clinic in a regional teaching hospital that has more than 6,000 births annually. Pregnant women usually take oral glucose tolerance test at 24–28 gestational weeks to diagnose GDM.

Eligible pregnant women were Zhengzhou citizens who were: (1) 18 years and older; (2) gestational age no more than 28 weeks; (3) have at least one risk factor for GDM, including (a) age ≥ 35 years; (b) pre-pregnancy body mass index (BMI) ≥24 kg/m2; (c) polycystic ovary syndrome; (d) family history of diabetes; (e) history of unexplained stillbirth, miscarriage, or neonatal death; (f) history of delivering a large baby (birth weight ≥ 4000g); or (g) history of GDM.38,39 Women were excluded if they had any contraindications to physical activity, including unexplained persistent vaginal bleeding; severe cardiovascular, respiratory, or systemic disease; incompetent cervix; multiple pregnancies; recurrent miscarriage; symptomatic anemia; type 1 diabetes; uncontrolled hypertension and thyroid disease.9

The present study aimed to conduct multiple linear regression analyses to explore the predictors of physical activity self-efficacy in pregnant women at high risk for GDM. According to Green (1991),40 the minimum required sample size for multiple linear regression can be estimated using the formula of n > 50 + 8 m, where m is the number of predictors. Based on the literature review, we assumed there may be 20 predictors of physical activity self-efficacy. Thus, in the present study, m is 20. Therefore, we needed at least 210 participants for sufficient statistical power for each multiple linear regression.

Measures

The Pregnancy Physical Activity Self-Efficacy Scale (P-PASES) measured physical activity self-efficacy in the present study.41 The original P-PASES was in English and translated and validated in Chinese pregnant women.42 The P-PASES is a 10-item instrument with each item rating on a 5-point Likert scale ranging from 5 points (strongly agree) to 1 point (strongly disagree). Higher scores indicate a greater level of self-efficacy to engage in physical activity. Physical activity self-efficacy can be divided into high (41–50 points), moderate (21–40 points), and low levels (10–20 points).41,42 The Chinese version of P-PASES has good psychometric properties, with a Cronbach’s alpha value of 0.80 and a test-retest reliability coefficient of 0.53.42 The Cronbach’s alpha value of P-PASES was 0.95 in the present study.

The Social Support for Physical Activity Scale (SSPAS) measured the social support for physical activity in the present study.43 The original SSPAS was in Chinese and for adults. The original SSPAS was adapted for Chinese pregnant women.43 The SSPAS was a 24-item instrument consisting of four subscales: emotional support, informative support, instrumental support, and peer support. Each item is rated on a 5-point Likert scale ranging from 1 (strongly disagree) to 5 (strongly agree). Higher scores indicate a higher level of social support for physical activity. The SSPAS has good psychometric properties, with Cronbach’s alpha value of 0.95 and a test-retest reliability coefficient of 0.88.43 The Cronbach’s alpha value of SSPAS was 0.98 in the present study.

The knowledge of pregnancy physical activity is a 7-item Chinese questionnaire and was used in the present study.44 The total scores range from 0 to 7. A score of 5 or more indicates a high awareness of pregnancy physical activity knowledge. The reported psychometric property of this questionnaire was suitable.44 The Cronbach’s alpha value of this questionnaire was 0.88 in the present study.

The 7-item Generalized Anxiety Disorder scale (GAD-7) was used to measure anxiety symptoms.45 Each item is rated on a 4-point Likert scale ranging from 0 to 3 with a total score of 0–21. Higher scores indicate a higher level of anxiety symptoms. The pregnant women who had a score ≥15 were referred to have further examination. The original GAD-7 was in English and has been validated in Chinese populations. The Chinese version of GAD-7 has good psychometric properties.46 The Cronbach’s alpha value of GAD-7 was 0.95 in the present study.

The Edinburgh Postnatal Depression Scale (EPDS) was used to measure depressive symptoms.47 The EPDS is a 10-item questionnaire. Each item is rated on a 4-point Likert scale ranging from 0 to 3 with a total score of 0–30. Higher scores indicate a higher level of depressive symptoms. The EPDS was originally in English and developed to measure postnatal depressive symptoms. It has been validated to measure antenatal depressive symptoms in Chinese pregnant women.48 Pregnant women with a score ≥13 were referred for further examination. The Cronbach’s alpha value of EPDS was 0.85 in the present study.

Intention to do physical activity was measured by a question with two options (yes or no). Firstly, all pregnant women were informed of the WHO pregnancy physical activity guideline, which states they should have at least 150 minutes of moderated physical activity weekly. Then, they were asked whether or not they intended to achieve the recommended level of physical activity during pregnancy (yes or no).

The sociodemographic and perinatal characteristics data sheet collected data, including maternal age, marital status, education, occupation, monthly household income; gestational age, parity, planned pregnancy, mode of conception, attending antenatal classes, having a habit of regular physical activity before pregnancy, already begun regular physical activity during this pregnancy, husband having a habit of regular physical activity, and environments or facilities around the community or work unit being appropriate for pregnant women to do physical activity.

Ethical Considerations and Procedure

Ethical approval was obtained from the Institutional Review Board of the Sixth Affiliated Hospital of Sun Yat-sen University (approval no. L2021ZSLYEC-098) on February 26, 2021 and the School of Nursing of Sun Yat-Sen University (no. L2022SYSU-HL-004) on January 13, 2022. The study conformed to the Code of Ethics of the World Medical Association (Declaration of Helsinki). All participants were assured that their participation was voluntary and that their data would be kept confidential. Pregnant women with a GAD-7 score ≥ 15 or EPDS score ≥ 13 were referred to a doctor or psychiatrist for further evaluation, but it would be up to the pregnant women to decide whether they would accept these services. This study did not envisage further follow-up of these women.

Four research assistants (RAs) who were nurses working in the antenatal clinic were selected to recruit and collect data. A training session was provided to ensure consistency. A pilot study was conducted on 10 pregnant women to assess the logistic issues and feasibility of the questionnaire. No problems were reported. The data of these pregnant women in the pilot study were not included in the present study.

The RAs checked all the medical records of those who had booked antenatal care in the study hospital and identified the eligible pregnant women. The RAs invited all eligible pregnant women to the antenatal clinic to participate in the study. After explaining the study’s purpose, women who signed an informed consent document were asked to fill in the questionnaires in a quiet room. The RAs stayed nearby to answer questions, if any, and received the returned questionnaires.

Data Analysis

Data were analyzed with SPSS v25.0 (IBM Corporation, Armonk, NY, USA). Statistical significance was set at 0.05. Descriptive statistics were used for demographic and obstetric characteristics and the study variables. Differences in physical activity self-efficacy among demographic and obstetric sub-groups were compared using the independent-sample t-test or one-way analysis of variance (ANOVA). Pearson’s correlation analysis was used to examine correlations between the study variables. All the variables with P < 0.05 in the above tests were inputted into a multivariate linear regression analysis to identify the predictors of physical activity self-efficacy. “Intention to do physical activity”, “Having already begun regular physical activity during pregnancy”, “Having attended antenatal classes”, and “Environment or facilities around the community or work unit being appropriate for pregnant women to do physical activity” were adjusted in multivariable analyses for physical activity self-efficacy.

Results

Of the 268 eligible pregnant women at high risk for GDM, 256 agreed to participate in the study. Four did not complete the questionnaires. Therefore, 252 pregnant women at high risk for GDM were included in this study, with a response rate of 94.0%.

Table 1 presents the pregnant women’s demographic characteristics. All pregnant women were married. The average age of the pregnant women was 30.81 ± 4.66 years old. Almost half of the pregnant women (44.8%) were overweight or obese with pre-pregnancy BMI above 24 Kg/m2. One hundred and forty- three pregnant women (56.7%) had an education level of junior college degree or below.

Table 1 Demographic Characteristics of Pregnant Women at High Risk for GDM (N = 252)

Table 2 presents the pregnant women’s perinatal characteristics. The average gestational age was 18.43 ± 4.56 weeks. About half of the pregnant women (45.2%) were nulliparous. Most (n = 239, 94.8%) have not begun regular physical activity during this pregnancy. Over one-third (35.9%) of pregnant women intended to do physical activity during pregnancy. One hundred and seventy-one pregnant women (67.9%) have not attended antenatal classes on physical activity. Internet (47.6%) was the most popular way to obtain knowledge of pregnancy physical activity. One hundred eighty-seven (74.2%) women’s husbands did not have regular physical activity habits.

Table 2 Perinatal Characteristics of Pregnant Women at High Risk for GDM (N = 252)

Table 3 presents the scores of each item of P-PASES in descending order. The mean total score of physical activity self-efficacy was 33.37 (SD = 7.51, range = 10–50). The items that had the lowest scores, suggesting the pregnant women felt least confident in physical activity, were “Do physical activity without consultation of my physician” and “Do physical activity even when I am feeling depressed”. The two items with the highest score were “Overcome barriers and challenges to do physical activity if I try hard enough”; and “Find the means and ways to do physical activity during pregnancy”. Most of them (n = 213, 84.5%) had a moderate level of physical activity self-efficacy, followed by a high level of physical activity self-efficacy (n =21, 8.3%), and a low level of physical activity self-efficacy (n = 18, 7.2%).

Table 3 The Scores on Physical Activity Self-Efficacy Listed by Item (N = 252)

Table 4 presents the mean score on social support for physical activity, knowledge of physical activity, anxiety and depressive symptoms. The mean score on social support for physical activity was 83.93 (SD = 16.79), suggesting the pregnant women had a moderate level of social support for physical activity. The highest level of social support for physical activity the pregnant women received was emotional support. The mean score of knowledge of physical activity in pregnancy was 3.13 (SD = 2.59) indicating a low level. More than half (n=167, 66.3%) of the pregnant women had a low level on awareness of pregnancy physical activity knowledge. The lowest awareness of the item on knowledge questionnaires was contraindications on physical activity for pregnant women (24.2%), followed by warning signs for pregnant women to stop physical activity (31.1%), the benefits of physical activity for the fetus (44.4%), the benefits of physical activity for pregnant women (49.2%), the mode of physical activity for pregnant women to avoid (47.6%), the benefits of physical activity for natural delivery (53.6%), and suitable modes of physical activity for pregnant women (62.3%). The mean score on anxiety and depressive symptoms was 2.93 (SD = 4.21) and 6.65 (SD = 5.49), respectively, which were in the normal value.

Table 4 Means, Standard Deviations, and Prevalence in Social Support for Physical Activity, Knowledge of Physical Activity, Anxiety and Depressive Symptoms (N = 252)

Table 5 presents the differences in physical activity self-efficacy among sociodemographic and perinatal characteristic sub-groups. Pregnant women who intended to do physical activity (t = 3.342, p < 0.01), had already begun regular physical activity during this pregnancy (t = 2.301, p < 0.05), had attended the antenatal classes (t = 3.369, p < 0.01), and lived in the community or work unit having the environments or facilities appropriate for pregnant women to engage in physical activity (t = 2.110, p < 0.05) reported higher scores in physical activity self-efficacy.

Table 5 Differences in the Physical Activity Self-Efficacy Among Various Socio-Demographic, and Perinatal Sub-Groups (N = 252)

Table 6 presents the correlations between physical activity self-efficacy and social support for physical activity, knowledge of physical activity, anxiety and depressive symptoms. Physical activity self-efficacy was positively related to social support for physical activity (r = 0.30, p < 0.001), knowledge of physical activity (r = 0.26, p < 0.001), and negatively related to anxiety symptoms (r = −0.19, p = 0.003). Depressive symptoms were not significantly related to physical activity self-efficacy.

Table 6 Associations Among Physical Activity Self-Efficacy, Social Support for Physical Activity, Knowledge of Physical Activity, Anxiety Symptoms, and Depressive Symptoms (N = 252)

Table 7 presents the predictors of physical activity self-efficacy. Variables that had a significant correlation with physical activity self-efficacy scores were included in the regression model. The best-fit regression model revealed four predictors that explained 17.5% of the variance in physical activity self-efficacy. The four predictors were social support for physical activity, knowledge of physical activity, intention to do physical activity, and anxiety symptoms.

Table 7 Predictors of the Physical Activity Self-Efficacy by Multivariate Linear Regression (N = 252)

Discussion

To our knowledge, this was the first study to examine physical activity self-efficacy and identify its predictors among pregnant women at high risk for GDM in mainland China. As the physiological and psychological changes during pregnancy, pregnant women may need a higher level of physical activity self-efficacy to achieve the recommended level of physical activity. Unfortunately, the present study found that as much as 91.7% of pregnant women in the present study had a low or moderate level of physical activity self-efficacy which was consistent with a previous study on pregnant women at low risk for GDM in mainland China.49 The physical activity self-efficacy in the present study was lower than that in American pregnant women at low risk for GDM in rural areas,33 and Danish pregnant women at low risk for GDM.50 The lower physical activity self-efficacy in the present study may be related to the traditional Chinese cultures.34 To avoid spontaneous miscarriage, Chinese pregnant women tend to obey traditional taboos such as “no jumping”, “no moving heavy objects”, “no fast walking”, and “not too much walking”.34 The findings suggested that most pregnant women at high risk for GDM in mainland China may need interventions to enhance their physical activity self-efficacy.

Further examining the items of P-PASES, we found that pregnant women were least confident in physical activity without consulting their physician. It may be because pregnant women regard the advice from their healthcare providers as reliable and credible.51 A previous study demonstrated that perinatal physical activity advice and counseling were crucial to promoting physical activity adherence during pregnancy.52

Unfortunately, nearly half the pregnant women in the present study attained information on physical activity from the internet, which could be inaccurate, confusing, and overwhelming.53 It may be because providing counseling on physical activity for pregnant women was not a routine service in the current antenatal care in mainland China as well as in Western countries such as the United Kingdom.54 Furthermore, healthcare professionals perceived promoting physical activity as being a burden due to a lack of training, knowledge, and resources.55 In fact, some pregnant women reported receiving incorrect or incomplete advice on the frequency, intensity, and type of physical activity, which did not follow updated evidence-based physical activity guidelines for pregnant women.56,57 A continued education program on current physical activity guidelines for pregnant women may encourage and help local healthcare providers provide expert counseling.

The present study found that social support was the strongest predictor of physical activity self-efficacy in pregnant women at high risk for GDM. Cheng et al,26 also found that greater social support was significantly associated with increased self-efficacy to engage in physical activity in pregnant women with low risk for GDM. This result supports Bandura’s self-efficacy theory, which states that social support is a resource for self-efficacy.19 The present study’s findings suggested that healthcare professionals should provide pregnant women with social support. They could provide information and emotional support, such as encouragement, positive feedback, and insurance on their physical activity. The previous study also indicated that pregnant women preferred to meet other women in the same situation to help normalize concerns following the ongoing pregnancy periods in the antenatal classes.58 In addition, perceiving others’ successful engagement in the targeted activity could help them enhance their self-efficacy to do physical activity during pregnancy.59 Providing opportunities for pregnant women to get peer support from other pregnant women may be helpful. Besides peer support, healthcare professionals could invite husbands/partners to participate in pregnant women’s physical activity.

The present study also found that knowledge of physical activity predicted physical activity self-efficacy. Women with a higher level of pregnancy physical activity knowledge were more confident in persisting in physical activity during pregnancy. However, 66.3% of pregnant women in the present study had a low awareness of pregnancy physical activity knowledge, which was higher than that in Ethiopia (44.2%).60 Antenatal classes are practical approaches to enhance pregnant women’s pregnancy physical activity knowledge. However, only one-third of the pregnant women in the present study attended the antenatal classes. A previous study also indicated that the use of the Internet as a source of health information has become increasingly popular among pregnant women.61 Considering the high prevalence of GDM in mainland China, online antenatal classes focused on physical activity during pregnancy should be developed for pregnant women at high risk for GDM.

This study also found that anxiety symptoms were a predictor of physical activity self-efficacy, which was consistent with the results of the study in non-pregnant women.30 This result also supports Bandura’s self-efficacy theory that negative emotion was a barrier to self-efficacy.19 The present study also found that the intention to do physical activity during pregnancy predicted physical activity self-efficacy. This result agreed with the literature that intention to do physical activity and physical activity self-efficacy were highly correlated in college students.29 However, over half of the pregnant women (64.1%) in the present study did not intend to engage in physical activity during pregnancy. Furthermore, a previous study showed that most (73.5%) of women who were already physically inactive reported no intention to engage in physical activity during pregnancy.16 Pregnant women reported that they did not plan to engage in physical activity during pregnancy due to a lack of counseling or guidance.62 Thus, professional knowledge and guidance regarding physical activity during pregnancy were urgent issues in the antenatal care system. Perhaps it is effective to encourage the whole society to engage in physical activity to enhance pregnant women’s physical activity.

Limitations

This study had some limitations. First, it was conducted in one hospital, and most participants had a high level of education. Our findings may not be transferable to other settings or those less educated. Second, the best-fit regression analysis revealed only 17.5% of the variance explaining physical activity self-efficacy. Further study is suggested to explore more factors related to physical activity self-efficacy among pregnant women at high risk for GDM.

Conclusions

The present study found that Chinese pregnant women at high risk for GDM had a moderate level of physical activity self-efficacy. Social support, knowledge, intention to do physical activity and anxiety symptoms were predictors of physical activity self-efficacy in pregnant women at high risk for GDM in mainland China.

Implications for Practice and Research

The present study suggested that most pregnant women at high risk for GDM need interventions for their physical activity self-efficacy. Healthcare professionals may use strategies to enhance pregnant women’s social support, knowledge of physical activity, and intention to do physical activity, as well as decrease their anxiety symptoms to enhance their physical activity self-efficacy. Online antenatal classes may be a practical approach to enhance pregnant women’s physical activity self-efficacy.

Acknowledgments

We would like to acknowledge all pregnant women who participated in this study. This paper’s abstract was presented as a poster at the ICHBPH 2023: International Conference on Health Behavior and Public Health with interim findings. The poster abstract was published in ‘Poster Abstracts’ in the World Academy of Science, Engineering and Technology International Journal of Social and Business Sciences.

Funding

This study was supported by the National Natural Science Foundation of China (Grant number 72174216).

Disclosure

The authors declare no competing interests.

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