Here is the design of a clinical trial:

Official Title: Impact of the Korea Early Childhood Home-visiting Intervention on Childhood Health and Development and Maternal Health: A Randomized Controlled Community Trial

Included conditions:
- Child Development
- Parenting
- Infant Development
- Pregnancy Related
- Maternal Distress

Study Armgroups:
- {'label': 'Targeted nurse-led home visiting', 'type': 'EXPERIMENTAL', 'description': "The intervention group will receive 25-29 home visits during pregnancy and the first 2 years of life conducted by child health nurses. The frequency of home visits will be determined by nurses based on the needs of the families. The content of each home visit is individually tailored to the mother's needs, skills, strengths, and capacity using parenting education materials.", 'interventionNames': ['Behavioral: Targeted nurse-led home visiting']}
- {'label': 'Control group', 'type': 'NO_INTERVENTION', 'description': 'The control group will receive existing maternal and child health services (usual care) except for the targeted nurse-led home visits.'}

Interventions:
- {'type': 'BEHAVIORAL', 'name': 'Targeted nurse-led home visiting', 'description': "The KECHI encompasses 25-29 home visits, group activities, and community service linkage by social workers from the prenatal period until the child reaches the age of 2 years; as such, it is a complex intervention involving various domains to address a wide range of outcomes. Pregnant women with two or more risk factors who are deemed to have difficulties in raising children are eligible for the targeted multiple nurse home visits. Each home visit is implemented based on families' needs, and individualized interventions are provided to improve parenting and the home environment in order to promote the child's health and development and maternal health. The program includes educational materials for parents, such as a booklet covering issues on prenatal care, child development, postnatal child care, parent-child attachment, play, communication, safety, and goal-setting.", 'armGroupLabels': ['Targeted nurse-led home visiting'], 'otherNames': ['KECHI (Korea Early Childhood Home-visiting Intervention)']}

Primary Outcomes:
- {'measure': 'Home environment', 'description': 'Home environment as assessed using IT-HOME (Infant-Toddler Home Observation for Measurement of Environment) when the child is 6 months old. IT-HOME (Infant-Toddler Home Observation for Measurement of Environment), composed of 45 items, was developed by Caldwell \\& Bradley (1984). The minimum score is 0 and the maximum score is 45, and a higher score means a better outcome.', 'timeFrame': 'when the child is 6 months old.'}
- {'measure': 'Home environment', 'description': 'Home environment as assessed using IT-HOME (Infant-Toddler Home Observation for Measurement of Environment) when the child is 12 months old. IT-HOME (Infant-Toddler Home Observation for Measurement of Environment), composed of 45 items, was developed by Caldwell \\& Bradley (1984). The minimum score is 0 and the maximum score is 45, and a higher score means a better outcome.', 'timeFrame': 'when the child is 12 months old.'}
- {'measure': 'Home environment', 'description': 'Home environment as assessed using IT-HOME (Infant-Toddler Home Observation for Measurement of Environment) when the child is 24 months old. IT-HOME (Infant-Toddler Home Observation for Measurement of Environment), composed of 45 items, was developed by Caldwell \\& Bradley (1984). The minimum score is 0 and the maximum score is 45, and a higher score means a better outcome.', 'timeFrame': 'when the child is 24 months old.'}
- {'measure': 'Emergency department visits due to injuries', 'description': 'Number of emergency department visits due to injuries when the child is 6 weeks old.', 'timeFrame': 'when the child is 6 weeks old.'}
- {'measure': 'Emergency department visits due to injuries', 'description': 'Number of emergency department visits due to injuries when the child is 6 months old.', 'timeFrame': 'when the child is 6 months old.'}
- {'measure': 'Emergency department visits due to injuries', 'description': 'Number of emergency department visits due to injuries when the child is 12 months old.', 'timeFrame': 'when the child is 12 months old.'}
- {'measure': 'Emergency department visits due to injuries', 'description': 'Number of emergency department visits due to injuries when the child is 24 months old.', 'timeFrame': 'when the child is 24 months old.'}
- {'measure': 'Child development (K-Bayley-III)', 'description': 'Child development as assessed using the K-Bayley-III (Korean Bayley Scales of Infant and Toddler Development-III) score when the child is 24 months old', 'timeFrame': 'when the child is 24 months old.'}
- {'measure': 'Breastfeeding duration', 'description': 'Breastfeeding duration when the child is 6 weeks old.', 'timeFrame': 'when the child is 6 weeks old.'}
- {'measure': 'Breastfeeding duration', 'description': 'Breastfeeding duration when the child is 6 months old.', 'timeFrame': 'when the child is 6 months old.'}
- {'measure': 'Breastfeeding duration', 'description': 'Maternal self-rated health when the child is 12 months old.', 'timeFrame': 'when the child is 12 months old.'}
- {'measure': 'Breastfeeding duration', 'description': 'Breastfeeding duration when the child is 24 months old.', 'timeFrame': 'when the child is 24 months old.'}
- {'measure': 'Maternal self-rated health', 'description': 'Maternal self-rated health when the child is 6 weeks old.', 'timeFrame': 'when the child is 6 weeks old.'}
- {'measure': 'Maternal self-rated health', 'description': 'Maternal self-rated health when the child is 6 months old.', 'timeFrame': 'when the child is 6 months old.'}
- {'measure': 'Maternal self-rated health', 'description': 'Maternal self-rated health when the child is 12 months old.', 'timeFrame': 'when the child is 12 months old.'}
- {'measure': 'Maternal self-rated health', 'description': 'Maternal self-rated health when the child is 18 months old.', 'timeFrame': 'when the child is 18 months old.'}
- {'measure': 'Maternal self-rated health', 'description': 'Maternal self-rated health when the child is 24 months old.', 'timeFrame': 'when the child is 24 months old.'}
- {'measure': 'Community service linkage', 'description': 'Community service linkage as measured by the number of community services a mother has received during the last year when the child is 12 months old.', 'timeFrame': 'when the child is 12 months old.'}
- {'measure': 'Community service linkage', 'description': 'Community service linkage as measured by the number of community services a mother has received during the last year when the child is 24 months old.', 'timeFrame': 'when the child is 24 months old.'}

Please estimate the sample size based on the assumption: 
The probability of type I error (alpha) was set at 0.05 (two-tailed) and type II error (beta) was set at 0.10 (power=90%). A 35% attrition rate was presumed for the primary outcome indicator at the 2-year follow-up.
Sample size
        We considered IT-HOME as a main outcome measure for sample size calculation. In our prior study,53 the mean IT-HOME score for children at 6â24 months post partum who received nurse home visitation services in Seoul was 32.5, and the SD was 5.0. Since we expect to recruit participants from more diverse backgrounds, we anticipated approximately 10% larger variations in IT-HOME scores. Effect sizes of 0.25â0.3 SDs are considered meaningful and impactful at the population level,54 55 so we set the difference in IT-HOME scores between intervention and control groups to 1.50. The probability of type I error (alpha) was set at 0.05 (two-tailed) and type II error (beta) was set at 0.10 (power=90%). The presumption of 35% attrition for the primary outcome indicator at the 2-year follow-up, reflecting a rate slightly higher than that reported in other studies,54 resulted in a sample size of 400 per group (800 total).