This study aims to evaluate the effectiveness of an online video-based developmental support program for parents of children aged 1-3 years receiving care at a Family Health Center. Approximately 60 parents will be randomly assigned to either an intervention group, which will receive a four-week online developmental support program, or a control group, which will continue to receive usual healthcare services. Data will be collected at baseline, two weeks after the intervention, and at one- and three-month follow-up assessments. The study will examine the effects of the online video-based developmental support program on parents' attitudes toward child development, developmental awareness, parenting self-efficacy, and the quality of the home environment that supports child development.

Study Design This study is a randomized controlled, parallel-group experimental trial with pre-test and post-test measurements.

Study Setting The study will be conducted at Şeyh Şamil Family Health Center, one of the Family Health Centers affiliated with the Sivas Provincial Health Directorate. The center was selected because it serves the highest number of children aged 12-36 months among the eligible centers. Child development is monitored according to the Infant, Child, and Adolescent Follow-up Protocol of the General Directorate of Public Health. Nurses provide developmental screening, immunization, anthropometric measurements, risk assessment, early intervention activities, and parental counseling services.

Population and Sample The study population consists of 310 parents with children aged 12-36 months. The sample size was calculated using G*Power version 3.1.9.4 software. Based on Cohen's criteria, a medium effect size (Cohen's d = 0.5), a 95% confidence level (α = 0.05), and 80% statistical power (1 - β = 0.80) were used. Accordingly, a minimum of 30 participants per group (total sample size = 60) was required for an independent samples t-test design. Considering a potential attrition rate of 20%, the final sample size was determined as 60 participants. Participants will be randomly assigned to either the intervention group (n = 30) or the control group (n = 30).

Eligibility Criteria Inclusion Criteria

• Being the parent of a child aged 12-36 months
• Child's growth percentile being between the 3rd and 97th percentiles
• Ability to speak and understand Turkish
• No prior participation in a similar developmental support program
• Having internet access and the ability to use a computer, tablet, or smartphone
• Completion of at least primary school education
• Ability to read and understand written materials
• Willingness to participate in the study Exclusion Criteria
• Missing at least one session of the intervention program
• Living in an extended family household
• Experiencing a major psychosocial event within the last six months (e.g., relocation, death of a first-degree relative, or divorce)
• Adolescent parenthood
• Having a child with a history of congenital anomalies, chronic illness, or prematurity
• Having a diagnosed mental health disorder Blinding Due to the nature of the intervention, participants and researchers cannot be blinded. However, statistical and reporting blinding will be implemented. Data will be coded without indicating group allocation, and statistical analyses will be conducted by an independent statistician.

Randomization Participants who meet the eligibility criteria will be assigned to either the intervention or control group using a simple randomization procedure conducted through an online randomization program.

Outcome Measures Primary Outcomes

• Score on the Psychosocial Developmental Attitudes Scale for Ages 0-6
• Score on the Mindful Parenting Scale
• Score on the Parenting Self-Efficacy Scale
• Score on the Home Observation and Measurement of the Environment Scale for Young Children Data Collection Instruments Data will be collected using the Family Information Form, the Psychosocial Developmental Attitudes Scale for Ages 0-6, the Mindful Parenting Scale, the Parenting Self-Efficacy Scale (Short Form), and the Home Observation and Measurement of the Environment Scale for Young Children.

Intervention Development The developmental support program will be developed based on a literature review and expert consultation. Content validity will be evaluated by experts in child development and pediatric nursing using the Davis technique. Each item will be rated on a four-point scale. A Content Validity Index (CVI) greater than 0.80 will be considered acceptable. The final program will consist of four modules, each containing two sessions. A pilot study involving five parents who are not included in the main study will be conducted to assess the feasibility of the intervention and the clarity of the data collection instruments. Revisions will be made based on participant feedback.

Intervention Procedures Participants in the intervention group will complete baseline assessments before receiving the developmental support program. The intervention will be delivered online over four weeks through video-supported sessions conducted via Zoom. Participants will attend one session per week in groups of approximately 15 parents. Each session will last 30-45 minutes. Process evaluation forms will be used to assess participation and satisfaction. Outcome measures will be repeated two weeks after program completion and at one-month and three-month follow-up assessments.

Control Group Participants in the control group will continue to receive routine primary healthcare services provided by the Family Health Center. Assessments will be conducted at the same time points as in the intervention group. After completion of the study, the developmental support program videos will be made available to participants in the control group.

Data Collection Methods Data will be collected through face-to-face interviews conducted either at the Family Health Center or in participants' homes. Written informed consent will be obtained before participation. Baseline, post-intervention, and follow-up assessments will be completed using standardized measurement instruments.

Data Analysis Data will be analyzed using IBM SPSS Statistics (Statistical Package for the Social Sciences). The normality of data distribution will be assessed using the Kolmogorov-Smirnov test and the Shapiro-Wilk test. For normally distributed data, independent samples t-tests and analysis of variance (ANOVA) will be used. For non-normally distributed data, the Mann-Whitney U test and Kruskal-Wallis test will be applied. Relationships between variables will be examined using Pearson correlation analysis or Spearman rank correlation analysis. Statistical significance will be defined as a p-value less than 0.05.

Inclusion Criteria:

• Parents with children aged 12-36 months
• Children with a percentile value between the 3rd and 97th percentile
• Able to speak and understand Turkish
• No previous participation in a similar program
• Having internet access and the ability to use a computer/laptop, tablet, or smartphone
• At least primary school graduates
• Able to read and comprehend written information
• Willing to participate in the study

Exclusion Criteria:

• Adolescent parents
• Parents of children with congenital anomalies, chronic diseases, or a history of prematurity
• Individuals with a diagnosed mental health disorder

Participation is limited to female participants who are mothers of children aged 12-36 months.

Individual participant data will not be shared in order to protect participant confidentiality and ensure privacy. All collected data will be anonymized and reported only in aggregate form. Individual-level data sharing is not planned due to ethical and data protection considerations.