Participants and Sampling The study population consisted of undergraduate nursing students enrolled in the Faculty of Health Sciences, Department of Nursing, at Eskişehir Osmangazi University. The study sample comprised 52 nursing students who agreed to participate during the study period and met the eligibility criteria. Participants were randomly assigned to either the intervention group (n = 26) or the control group (n = 26) using a simple randomization procedure.
The required sample size was determined using G*Power software (version 3.1.9.7). The calculation was based on a moderate-to-large effect size (d = 0.70), a significance level of α = .05, and a statistical power of 0.80. The analysis indicated that a minimum of 23 participants per group was required. Considering the possibility of missing data and participant attrition, the sample size was increased to 26 students per group.
Purposive sampling, a non-probability sampling method, was employed to recruit participants. This sampling strategy was selected to ensure the inclusion of nursing students who had received theoretical instruction in pregnancy nutrition counseling and were eligible to participate in the simulation-based educational intervention.
Eligible participants were undergraduate nursing students who voluntarily agreed to participate in the study and had not previously received simulation training on a similar topic. Students who failed to participate throughout the study or who submitted incomplete pretest or posttest questionnaires were excluded from the analysis.
Randomization and Blinding Participants were allocated to the intervention and control groups using a simple randomization procedure. After eligible and consenting students had been assigned identification numbers, a computer-generated random number sequence was used to allocate participants to either the intervention group (n = 26) or the control group (n = 26). The randomization process was performed by an independent researcher who was not directly involved in the study.
To ensure allocation concealment, group assignments were placed in sequentially numbered, sealed, opaque envelopes. As each participant was enrolled, the corresponding envelope was opened to determine group assignment.
Because of the nature of the educational intervention, blinding of participants and instructors was not feasible. Therefore, the study was designed as a single-blind randomized controlled trial. Outcome assessment was performed by independent assessors who were unaware of participants' group allocation using a standardized clinical skills checklist. Data analysts were also blinded to group allocation by coding the study groups.
Data Collection Procedure Data collection was initiated after obtaining ethical approval and institutional permission and was conducted in three sequential phases: (1) pretest assessment, (2) scenario-based simulation training, and (3) posttest assessment and clinical skill evaluation.
After written informed consent had been obtained, baseline data on participants' anxiety levels and perceived self-efficacy were collected using the pretest instruments.
Participants in the intervention group then completed a researcher-developed scenario-based simulation program on pregnancy nutrition counseling. The simulation replicated an outpatient clinic setting, and each simulation session lasted approximately 20 minutes.
Immediately after the simulation, participants attended a structured debriefing session lasting approximately 20 minutes to reflect on their clinical experiences, identify strengths, and discuss areas for improvement. Following the debriefing session, participants completed the posttest instruments. Clinical skill performance was subsequently evaluated using the Pregnancy Nutrition Counseling Skills Checklist developed by the researchers.
Data Collection Tools The study data were collected using the Participant Information Form, the State Anxiety Inventory (SAI), the Beck Anxiety Inventory (BAI), the Nursing Learning Self-Efficacy Scale (NLSES), and the Pregnancy Nutrition Counseling Skills Checklist.
Participant Information Form The Participant Information Form was developed by the researchers based on the relevant literature to obtain participants' sociodemographic characteristics, academic characteristics, clinical experience, and previous simulation experience. The form consists of 15 items.
State Anxiety Inventory (SAI) The State Anxiety Inventory (SAI) was used to assess participants' state anxiety levels. The original instrument consists of two 20-item subscales measuring state and trait anxiety; however, only the State Anxiety Inventory was used in the present study. Each item is rated on a four-point Likert scale ranging from 1 ("Not at all") to 4 ("Very much so"). Total scores range from 20 to 80, with higher scores indicating higher levels of state anxiety. The Cronbach's alpha coefficient of the scale in the present study was 0.966.
Beck Anxiety Inventory (BAI) The Beck Anxiety Inventory (BAI) was used to evaluate the severity of anxiety symptoms experienced during the previous week. The instrument consists of 21 self-report items scored on a four-point scale (0-3), yielding total scores ranging from 0 to 63. Higher scores indicate greater anxiety severity.
Total scores are interpreted as follows:
0-7: Minimal anxiety 8-15: Mild anxiety 16-25: Moderate anxiety 26-63: Severe anxiety The Cronbach's alpha coefficient of the Beck Anxiety Inventory in the present study was 0.962.
Nursing Learning Self-Efficacy Scale The Nursing Learning Self-Efficacy Scale (NLSES) was used to evaluate nursing students' perceived self-efficacy regarding learning and clinical practice.The original scale consists of 21 items and five subdimensions: conceptual understanding, higher-order cognitive skills, practical work, everyday application, and nursing communication. In the Turkish adaptation, one item was removed, and the practical work and everyday application subdimensions were merged, resulting in a 20-item scale with four subdimensions: conceptual understanding, higher-order cognitive skills, nursing communication, and everyday practical applications.The Cronbach's alpha coefficient of the scale in the present study was 0.993.
Pregnancy Nutrition Counseling Skills Checklist Students' clinical skill performance was evaluated using the Pregnancy Nutrition Counseling Skills Checklist developed by the researchers. The checklist consists of 18 items covering therapeutic communication, history taking, assessment of maternal nutritional status, identification of gestational diabetes mellitus risk factors, development of individualized nutrition counseling plans, application of motivational interviewing techniques, patient education, and follow-up planning. Each item is rated as "Performed," "Partially Performed," or "Not Performed," providing a standardized assessment of students' clinical performance during the simulation. The checklist demonstrated excellent internal consistency in the present study, with a Cronbach's alpha coefficient of 0.989.
