Here is the design of a clinical trial:

Official Title: Manual Acupuncture vs Sham Acupuncture and Usual Care for the Prevention of Primary Dysmenorrhea: A Multicenter, Randomized, Controlled, Clinical Trial

Included conditions:
- Primary Dysmenorrhea

Study Armgroups:
- {'label': 'Verum acupuncture', 'type': 'EXPERIMENTAL', 'description': 'Participants will receive verum acupuncture plus usual care. Participants will receive acupuncture treatment start from the 5th or 7th day before the estimated first day of menstrual cycle, and for each cycle, participants will receive one session of treatment each day for 5 consecutive days, totally be treated with 15 sessions.Verum needles will be inserted into the skin and manipulated manually until deqi occurs. The needles are retained for 30 min in each session. During the treatment, the acupuncturist inquires the patient about deqi sensations and manipulates the needles to maintain the intensity of deqi. Participants will receive the same usual care as those in the usual care group.', 'interventionNames': ['Device: Verum acupuncture', 'Behavioral: Usual care']}
- {'label': 'Sham acupuncture', 'type': 'SHAM_COMPARATOR', 'description': 'Participants will receive sham acupuncture plus usual care. The Streitberger placebo needle will be placed at non-acupuncture points which are distant from the meridian parts and not located on the same neuromuscular segments as the prescribed points used in the VA group, so as to minimize any therapeutic and segmental effects. The same acupuncture schedule as that in the verum acupuncture group will be applied. The needles are retained for 30 min in each session. During the treatment, the acupuncturist inquires the patient about deqi sensations and pretends to manipulate the needles but deqi is not sought.Participants will receive the same usual care as those in the usual care group.', 'interventionNames': ['Device: Sham acupuncture', 'Behavioral: Usual care']}
- {'label': 'Usual care', 'type': 'PLACEBO_COMPARATOR', 'description': 'Participants will not receive acupuncture treatment besides health education as a control group.', 'interventionNames': ['Behavioral: Usual care']}

Interventions:
- {'type': 'DEVICE', 'name': 'Verum acupuncture', 'description': 'Participants allocated to VA group will receive traditional acupuncture treatment on the "Guanyuan"(RN 4), bilateral "Sanyinjiao"(SP 6), bilateral "Zigong"(EX-CA1), bilateral "Xuehai"(SP 10). Additional points will be chosen according to TCM syndrome differentiation constitution of patients. If patients with deficient syndrome, bilateral "Zusanli" (ST 36) will be included. If patients with sufficiency syndrome, bilateral "Diji" (SP 8) will be included. The NO.16 special type of acupuncture needle (0.30 x 30 mm) produced by German asia-med company will be applied.The needles will be inserted into the skin of acupuncture points and manipulated manually by using the techniques such as lifting, thrusting, and twirling, until the internal compound sensation known as deqi.', 'armGroupLabels': ['Verum acupuncture']}
- {'type': 'DEVICE', 'name': 'Sham acupuncture', 'description': 'We use a non-insertive sham control produced by Asia-med Company in Germany-the streitberger placebo-needle. Sham points are described as follows: 1) 5 inch lateral to the seventh thoracic spine; 2) 5 inch lateral to the eighth thoracic spine; 3) 5 inch lateral to the ninth thoracic spine; and 4) 5 inch lateral to the tenth thoracic spine.', 'armGroupLabels': ['Sham acupuncture']}
- {'type': 'BEHAVIORAL', 'name': 'Usual care', 'description': 'Patients in usual care group will not receive acupuncture treatment but enhance usual care by providing them with detailed information via propaganda booklets or the internet in the form of health education.', 'armGroupLabels': ['Sham acupuncture', 'Usual care', 'Verum acupuncture']}

Primary Outcomes:
- {'measure': 'Change of Cox Menstrual Symptom Scale (CMSS) in a menstrual cycle compared to baseline.', 'timeFrame': 'At baseline (one menstrual cycle/one month before randomization), the first，second, third, fourth, fifth, and sixth month after randomization.'}

Please estimate the sample size based on the assumption: 
Superiority design with a power level of 80% and a significance level set at 5%. For the verum vs. sham acupuncture comparison, a 1:1 ratio is used. For the verum acupuncture vs. usual care comparison, a 2:1 ratio is used. An attrition rate of 20% is considered.
Sample size
        The sample size was estimated using the Statistical Analysis System software program (version 9.3; SAS Institute Inc., Cary, NC, USA). According to our pilot trial, we anticipate a greater CMSS score decline of 0.2âÂ±â0.55 in the verum acupuncture group compared with the sham acupuncture group. This sample size calculation is based on a superiority design with a power level of 80% and a significance level set at 5%, with a 1:1 ratio. Based on these assumptions, 170 patients will be needed, with 85 patients in each group. Moreover, we anticipate a greater CMSS score decline of 0.5âÂ±â1.15 in the verum acupuncture group compared with the usual care group. This sample size calculation is based on a superiority design with a power level of 80% and a significance level set at 5%, with a 2:1 ratio. Based on these assumptions, 150 patients will be required, including 100 patients in the verum acupuncture group and 50 patients in the usual care group. This sample size will be inflated to 300 to account for an attrition rate of 20%. Thus, we plan to enroll 300 patients, including 120 patients in the VA and SA groups and 60 patients in the usual care group.