Study design:
A sequential mixed methods approach was conducted based on the Ottawa Decision Support Framework (ODSF). The current study will represent Aim 4 (Intervention implementation phase), comprising two stages. Stage 1 involves a randomized pre-test and post-test experimental design. Decisional conflict, knowledge, birth preference, and decision aid acceptability are assessed. Stage 2 consists of a survey, actual birth outcome and satisfaction are assessed.
Setting and participants:
The study will be conducted in a medical center in northern Taiwan. The medical center offers 24-hour system of the designated obstetrician. Using purposive sampling, the selection criteria include women who are medically eligible for VBAC in the study site, had experienced one previous CS, 14-16 weeks' gestation, had at least a half year interval between current pregnancy and the previous birth and are fluent in English or Mandarin. Exclusion criteria included women with multiple pregnancy, previous classic CS or myomectomy, and/or pregnancy with high risk of complications (for example, women who had risk factors such as hypertension, heart disease, diabetes, epilepsy, threatened premature labor, or another pre-existing medical problem).
Randomization:
Prior to the study commencing, the research team will conduct online discussions to clarify the research protocol. Eligible participants will be provided information about the study by the principal researcher and signed a written consent. Using computer permuted block randomization, participants will be allocated to control group (usual care) and intervention group (usual care plus the interactive web-based birth decision aid). After administering the baseline questionnaire, women will be allocated to the intervention group and give instructions by the principal researcher on how to log in the interactive birth decision aid platform/App. All participants confirm preferred mode of birth with their obstetrician prior to completing the second questionnaire.
Usual care:
A maternal health booklet, produced by Health Promotion Administration, Ministry of Health and Welfare, Executive Yuan, Taiwan, will be provided to all women. The booklet consists of 58 pages, presenting 5 "Dos" and 5 "Don'ts" during pregnancy. 5 "Dos" content included (1) Do receive prenatal exams according to schedule; (2) Do take good care during pregnancy; (3) Do recognize pregnancy complications; (4) Do know the signs of premature birth; (5) Do know the signs of labor. 5 "Don'ts" content included (1) Do not smoke or drink; (2) Do not be exposed to secondhand smoke; (3) Do not take medication without doctor's orders; (4) Do not choose a C-section in order to pick the time of birth; (5) Do not use drugs (52). There is very limited information relevant to mode of birth choice after caesarean.
Intervention:
Women in the intervention group will receive both usual care and decision support (an interactive web-based birth decision aid ). The interactive web-based birth decision aid will be modified from Professor Allison Shorten (English audio). We add communication aid at the beginning of platform/App. The communication aid comprises two components: components 1-how to participate in SDM and apply three talk to work together with clinicians (10 minutes) ; component 2-practice communication skill (10 minutes). Women will be assisted to create a unique username and password for secure decision aid access and its features and functions will be demonstrated. Intervention women will be invited to access the decision aid at home. All women are allowed to have many opportunities to access and use the decision aid during their pregnancy and will be recorded. They are encouraged to use the decision aid during recruitment and gestation visit in the Outpatient Department of Obstetrics. The principal researcher will provide 2-3 online consultations for individual women.
Outcome measures :
There are three primary and two secondary outcome measures. Primary outcome measures are decisional conflict, knowledge, birth preference and decision aid acceptability. Decisional conflict score (DCS)includes 16 questions in 5 sub-scale. Using the 5-point Likert 5 rating, from "strongly agree" ( 0 points) to "strongly disagree" (4 points). Knowledge measurement consists of a 15-item questionnaire asking participants to answer ''true,'' ''false,'' or ''unsure'' to a series of statements regarding risks and benefits of each birth mode. Previously tested Cronbach α for this questionnaire was = 0.67.
Secondary outcome measures are actual birth outcome and satisfaction. Satisfaction with decision scale (SWD) included six questions to measure women's satisfaction with their decision, using the Likert 5 rating, from "strongly agree" (5 points) to "strongly disagree" (1 points). Women have higher scores indicating increased SWD. Cronbach's α previously tested was 0.88.
Sample size :
Using G-POWER 3.1.9.2 software, sample size was calculated. Based on estimates from a previous pilot study, effect size=.40, a total of sample size 156 provides α = .05 and power = .80. To allow for preterm deliveries, mal-presentations, and losses to follow-up, an increase in the desired number by 10 percent would be 172.
Data collection and procedures :
Eligible women will be invited to participate in the study when they attend prenatal examination at the 14-16 weeks' gestation visit in the Outpatient Department of Obstetrics and Gynecology. After participants sign written consent for participation, women will be allocated to either the intervention group or control group. All participants will complete "personal basic information", "decision conflict scale" and "knowledge scale" in a quiet room. After completion of questionnaires, an interactive birth decision aid platform/App will be provided for intervention group women to discuss with their families at home. Individual consultations will be provided for intervention group women, by the principal researcher, at least twice during the 17-34 weeks' gestation period. All participants will complete "decision conflict scale" and "knowledge scale" and "decision aid acceptability at 35-38 weeks' gestation. A follow-up is held one month after birth. Postnatal women will be asked about "actual birth outcomes '' and complete a "satisfaction" questionnaire when they attend their postnatal examination visit .
Data analysis:
Quantitative data is managed and analyze using IBM SPSS Version 26.0. In terms of DCS and knowledge scores, matched pairs t-tests are used to compare differences between groups in change between pre and post test scores.
