The authors concluded that, although the included trials showed acupuncture may be beneficial to patients with premenstrual syndrome, there was insufficient evidence to support this conclusion due to methodological flaws in the trials. The authors' cautious conclusions reflect the evidence presented and are likely to be reliable.

To assess the effectiveness and adverse effects of acupuncture for the symptomatic treatment of premenstrual syndrome.

The Cochrane Library, MEDLINE, EMBASE, SCOPUS, Current Controlled Trials, National Centre for Complementary and Alternative Medicine, Complementary and Alternative Medicine Specialist Library, Japan Science and Technology Information Aggregator Electronic database, and a number of Korean and Chinese databases were searched to January 2009. Search terms were reported. Reference lists, relevant journals, symposia, and conference proceedings were handsearched (details not reported). Experts in complementary medicine and manufacturers of acupuncture equipment were consulted. No language restrictions were applied.

Randomised controlled trials (RCTs) that compared any form of acupuncture only with control for the treatment of women with premenstrual syndrome (meeting medically defined diagnostic criteria for premenstrual syndrome or premenstrual dysphoric disorder) were eligible for inclusion. Eligible control groups were no treatment, placebo, and pharmacologic or non-pharmacologic treatments for the alleviation of symptoms. The primary outcome was the improvement of overall or particular symptoms. A secondary outcome was adverse events.

Interventions varied between included trials: acupuncture alone or with acupoint injection, auricular acupuncture, and acupuncture catgut embedding. Control groups included waiting list, sham acupuncture, herbal medication (xiaoyao pills), or pharmacological treatment with fluoxetine, diazepam, or medroxyprogesterone. Duration of treatment ranged from 14 days to three menstrual cycles. The authors reported that outcomes were measured using different instruments across the trials. The mean age of participants ranged from 25 years to 32 years. Most of the trials were conducted in China; some were conducted in Korea and Croatia.

One reviewer identified studies from titles and abstract, with reference to a second reviewer where there was uncertainty regarding eligibility. Two reviewers independently assessed papers for inclusion. Disagreements were resolved through discussion.

Validity was assessed independently by two reviewers using methods described by Cochrane and included assessment of adequacy of allocation sequence generation, allocation concealment and blinding, incompleteness of outcome data, selective outcome reporting, and confounders.

Two reviewers independently extracted data to calculate standardised mean differences (SMDs) and 95% confidence intervals (CIs) for changes in premenstrual syndrome symptoms scores. Odds ratios (ORs) and 95% confidence intervals were calculated for changes in the responder rate for improved premenstrual syndrome symptoms or successful treatment. Authors were contacted for additional information where necessary.

Data were grouped according to control condition and combined in a narrative synthesis.

Nine RCTs (n=545 participants) were included in the review. Four RCTs reported adequate allocation sequence, two reported adequate allocation concealment, two reported adequate blinding, eight RCTs reported incomplete outcome data being adequately addressed, and three RCTs reported that selective outcome reporting and confounders were adequately addressed.

Acupuncture versus sham acupuncture (two RCTs): One RCT reported a significantly higher success rate for acupuncture (77.8%) compared with sham acupuncture (5.6%), but one RCT reported no statistically significant differences between groups.

Acupuncture versus waiting-list control (one RCT): A significant reduction in premenstrual syndrome symptoms was reported for hand acupuncture compared with waiting-list control (SMD 1.50, 95% CI 0.26 to 2.74).

Acupuncture versus pharmacologic treatment (four RCTs): Significant improvements of premenstrual syndrome symptoms were reported for acupuncture at acupoints on the bladder meridian compared to pharmacological interventions for two RCTs (SMD 1.09, 95% CI 0.42 to 1.76 and OR 6.00, 95% CI 1.48 to 24.30). Significant improvements were also reported for acupuncture plus acupoint injection (OR 4.17, 95% CI 1.24 to 13.97; one RCT) or acupoint catgut embedding (OR 5.13, 95% CI 1.33 to 19.71; one RCT) compared to pharmacological treatment. No significant differences were reported between acupuncture at classical acupoints and pharmacological treatment (one RCT).

Acupuncture versus herbal medicine (two RCTs): There were no significant differences between groups for improvement of premenstrual syndrome symptoms for acupuncture compared with herbal medicine.

Adverse events (two RCTs): One RCT reported one participant had developed a small subcutaneous haematoma following acupuncture at acupoint CV6. The other RCT reported no adverse events.

Although the included trials showed that acupuncture may be beneficial to patients with premenstrual syndrome, there was insufficient evidence to support this conclusion due to methodological flaws in the trials.

The review question was clear and supported by detailed inclusion and exclusion criteria. Several relevant sources were searched and no language restrictions were applied, reducing the potential for language bias. Although no formal assessment of publication bias was conducted, the authors reported the review was unlikely to be free from publication bias. Appropriate review methods were used to reduce reviewer bias and error.

An appropriate trial quality assessment was conducted and the results were reported. A narrative synthesis was appropriate given the variation between trials in terms of intervention and control groups. Some trial details were reported in the table, but reporting of outcomes was minimal.

The authors' cautious conclusions reflect the evidence presented and are likely to be reliable.

Practice: The authors did not report any implications for practice.

Research: The authors stated that further large, robust, placebo-controlled RCTs are required using rigorous methodology (randomisation, blinding, adequately concealed allocation and validated outcome measures). Future trials should follow the CONSORT statement and STRICTA recommendations (for acupuncture trials) and also report data on adverse effects.

Not stated.

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.