Here is the design of a clinical trial:

Official Title: A Randomized Double-blind Controlled Trial on the Effect of Vitamin D on Ovulation Rate of Women With Polycystic Ovary Syndrome

Included conditions:
- Polycystic Ovary Syndrome
- Anovulation

Study Armgroups:
- {'label': 'Vitamin D', 'type': 'ACTIVE_COMPARATOR', 'description': 'Vitamin D 50,000 IU/ week for 4 weeks, followed by 50,000 IU once every 2 weeks for 52 weeks Those who remain anovulatory after 6 months will be treated with a 6-month course of letrozole (2.5mg to 7.5mg for 5 days per cycle titrated according to response) for ovulation induction.', 'interventionNames': ['Dietary Supplement: Vitamin D']}
- {'label': 'Placebo', 'type': 'PLACEBO_COMPARATOR', 'description': 'Placebo tablets with same external appearance for 52 weeks Those who remain anovulatory after 6 months will be treated with a 6-month course of letrozole (2.5mg to 7.5mg for 5 days per cycle titrated according to response) for ovulation induction.', 'interventionNames': ['Other: Placebo']}

Interventions:
- {'type': 'DIETARY_SUPPLEMENT', 'name': 'Vitamin D', 'description': 'Vitamin D supplementation', 'armGroupLabels': ['Vitamin D']}
- {'type': 'OTHER', 'name': 'Placebo', 'description': 'Placebo tablets with the same external appearance', 'armGroupLabels': ['Placebo']}

Primary Outcomes:
- {'measure': 'Ovulation rate', 'description': 'Serum progesterone', 'timeFrame': '12 months'}

Please estimate the sample size based on the assumption: 
At least 80% power to detect the difference of 20% between the groups with type I error of 0.05. Accounting for 20% dropouts.
Sample size calculation
          The ovulation rate in Chinese women after taking letrozole is about 60%.26 Assuming the ovulation rate is increased to 80% after taking vitamin D, 91âwomen in each group will achieve at least 80% power to detect the difference of 20% between the groups with type I error of 0.05. Accounting for 20% dropouts, then 110âwomen per arm and 220âwomen are needed in total.