Study design and setting
A cross-sectional descriptive study was conducted from June 7 to December 7, 2020, in Changsha, China. Changsha is a subprovincial city located in the south-central part of China, and is the capital of Hunan Province, and has a population of approximately 8 million. The birth rate in Changsha is over 5,000 babies per year.
Women during the third trimester of pregnancy who were receiving antenatal care at the study hospitals during the study period were recruited. The inclusion criteria were as follows: (1) being older than 18 years, (2) having a history of CS(s); (3) being able to understand the content of the questionnaires, and (4) providing consent to participate. Women with concurrent major physical or mental health problems were excluded.
Sample size determination and sampling procedure
The required sample size was determined using a single population formula based on the assumption of a 95% confidence interval with a margin of error of 5%. Three hospitals were chosen (The Second Xiangya Hospital, Hunan Provincial People’s Hospital and Changsha Maternal and Child Health Hospital) that are purposively dependent on antenatal services and obstetrics care. The annual delivery rate of each hospital is approximately 4,000 live births. The sample was apportioned to every hospital by investigating the number of deliveries earlier in the year until the complete sample was obtained.
In this study, the Childbirth Attitude Questionnaire (CAQ), which was developed by Lowe in 2000 , was used to measure FOC. The CAQ is a 16-item questionnaire that uses a 4-point Likert scale. The item scores are summed to provide a total score (range 16-64), with higher scores indicating higher levels of FOC. The Chinese version of the CAQ has been used with good reliability and validity . The Cronbach’s alpha for the scale was 0.92. For the classification of no, low, moderate and severe levels of FOC, the cutoff values were 16, 28, 40, and 52, respectively.
The short form of the 32-item Chinese Childbirth Self-Efficacy Inventory (CBSEI-C32)  was used in this study to measure childbirth self-efficacy. The scale has two parallel subscales—the outcome expectancy subscale and the efficacy expectancy subscale—which consist of the same 16 items measuring coping behavior for childbirth on a 4-point Likert scale. The sum of the each subscale is the total score (range 32-128), with higher scores indicating higher levels of childbirth self-efficacy. The scale has a reported Cronbach's alpha value of 40.90 and has been shown to be a valid and reliable measure in Mainland China .
The Social Support Rating Scale (SSRS), which was developed by Xiao , was used to measure social support in this study. There are 10 items in this scale, including three dimensions—objective support (3 items), subjective support (4 items) and the utilization of social support (3 items). The sum of each dimension is the total score, with higher scores indicating higher levels of social support. The scale has Cronbach's alpha values of 0.825-0.896 and has been used widely in China .
Demographic and obstetric data included age (<35/≥35), pregnant women who were the only child in their families (no/yes), residential area (rural/urban), education (elementary school and below/junior high school/senior high school/college and above), occupation (office clerk/agricultural worker/self-employed/freelance), self-rated economic status (poor/fair/good), number of CSs (1/≥2), and experience with previous CS (no or mild fear/moderate or severe fear).
Procedures and ethical consideration
Ethical approval was obtained from the university and the study hospital. Participation in the study was voluntary, and all participants provided written informed consent before participation.
After obtaining ethical approval, a pilot study was conducted with 10 eligible subjects to evaluate the feasibility of the study and identify any unpredictable data collection problems, and no problems were reported. Training for data collectors was provided to ensure the accuracy and consistency of data collection. All eligible subjects who were waiting for their appointment in the obstetric clinic of the research hospital were invited to participate in the study. After providing informed consent, participants were asked to complete the demographic and obstetric questionnaire, the CAQ, the CBSEI-C32 and the SSRS. Data collectors remained in the vicinity to answer questions and personally collected the returned questionnaires.
Data processing and analysis
After data collection, all collected questionnaires were checked for completeness and internal consistency to exclude missing or inconsistent data. Data were entered and analyzed using IBM SPSS for Windows, version 16.0 (SPSS Inc., Chicago, IL, USA). Mean (M), standard deviation (SD), frequency and percentage were used to describe demographic and obstetric data, CAQ, CBSEI-C32 and SSRS scores. Independent sample t-test and analysis of variance were used to compare the CAQ scores with different demographic and obstetric characteristics. Pearson correlation coefficients were calculated to measure the relationships among CBSEI-C32, SSRS, and CAQ. If p < 0.05 in the above tests, then significant variables were entered in the multiple linear regression analysis to predict FOC. The variance inflation factor (VIF) was used to assess multicollinearity among the predictors.