Here is the design of a clinical trial:

Official Title: A Phase II, Randomized, Double-Blind, Placebo-Controlled Study of the Efficacy and Safety of Perinatal Tissue Mesenchyme Stem Cells in the Treatment for Caesarean Section Scars

Included conditions:
- Cicatrix

Study Armgroups:
- {'label': 'Mesenchymal Stem Cells low-dose group', 'type': 'EXPERIMENTAL', 'description': 'Target dose of 3 million Mesenchymal Stem Cells', 'interventionNames': ['Biological: Mesenchyme Stem Cells low-dose group']}
- {'label': 'Mesenchymal Stem Cells high-dose group', 'type': 'EXPERIMENTAL', 'description': 'Target dose of 6 million Mesenchymal Stem Cells', 'interventionNames': ['Biological: Mesenchyme Stem Cells high-dose group']}
- {'label': 'Placebo', 'type': 'PLACEBO_COMPARATOR', 'description': 'Placebo without Mesenchyme Stem Cells', 'interventionNames': ['Biological: Placebo']}

Interventions:
- {'type': 'BIOLOGICAL', 'name': 'Mesenchyme Stem Cells low-dose group', 'description': 'Participants will receive transdermal one dose of 1\\*10\\^6 cells of Perinatal Tissue Mesenchyme Stem Cells in the gel once a day for continuous three days and then receive transdermal placebo without of Perinatal Tissue Mesenchyme Stem Cells in the gel once a day for continuous next three days.', 'armGroupLabels': ['Mesenchymal Stem Cells low-dose group']}
- {'type': 'BIOLOGICAL', 'name': 'Mesenchyme Stem Cells high-dose group', 'description': 'Participants will receive transdermal one dose of 1\\*10\\^6 cells of Perinatal Tissue Mesenchyme Stem Cells in the gel once a day for continuous six days.', 'armGroupLabels': ['Mesenchymal Stem Cells high-dose group']}
- {'type': 'BIOLOGICAL', 'name': 'Placebo', 'description': 'Participants will receive transdermal placebo without of Perinatal Tissue Mesenchyme Stem Cells in the gel once a day for continuous six days.', 'armGroupLabels': ['Placebo']}

Primary Outcomes:
- {'measure': 'Change of Vancouver Scar Scale (VSS)', 'description': 'The investigators measured quartile grading scale at 1st, 3rd and 6th months of study and evaluated the change of the scale', 'timeFrame': '1st, 3rd, 6th month post treatment'}

Please estimate the sample size based on the assumption: 
The significance level (α) is 0.05, the power (β) is 0.1, and the ratio of MSC to control group sample size is 2:1.
Sample size
        Our sample size calculation is based on previous results from Professor Yu-Chen Huangâs preliminary trial in Taipei Medical University WanFang Hospital [42]. These results found that the mean VSS was 4.50âÂ±â1.68 in healthy pregnant women. The ratio of the MSC and control group sample size sets was 2:1. We will use the conventional values Î±â=â0.05 and Î²â=â0.1 for two-sided tests of probability. Meanwhile, we hypothesize that the difference in mean VSS at 6 months after treatment between the MSCs and placebo group will be Î´â=â1.5. The total sample size is estimated to be 74. Considering a dropout and other potential influencing factors, the final participant is estimated to be about 90 (nâ=â30 in each group).