Summary of findings 2. Acupuncture compared to no treatment for premenstrual syndrome.

Acupuncture compared to no treatment for premenstrual syndrome
Patient or population: women with PMS Setting: community Intervention: acupuncture Comparison: no treatment
Outcomes	Anticipated absolute effects* (95% CI)		Relative effect (95% CI)	№ of participants (studies)	Certainty of the evidence (GRADE)	Comments
	Risk with no treatment	Risk with Acupuncture
Overall premenstrual symptoms at end of treatment. Assessed with the Menstrual Symptom Severity List (MSSL). Scale range 0‐33. Lower scores indicate less severe symptoms.	The mean overall premenstrual symptom score was 17.54	MD 13.60 lower (15.70 lower to 11.50 lower)	‐	14 (1 RCT)	⊕⊝⊝⊝ VERY LOW 1 2	Due to the very low quality of the evidence, we are uncertain whether acupuncture reduces PMS symptoms compared to a no treatment control
Adverse events at end of treatment	0 per 1000	0 per 1000 (0 to 0)	not estimable	20 (1 RCT)	⊕⊝⊝⊝ VERY LOW 1 3	Neither group reported any adverse events
Specific PMS symptoms ‐ not measured	‐	‐	‐	‐	‐	No studies reported on this outcome
Response rate ‐ not measured	‐	‐	‐	‐	‐	No studies reported on this outcome
Quality of Life ‐ not measured	‐	‐	‐	‐	‐	No studies reported on this outcome
*The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: Confidence interval; MD: mean difference
GRADE Working Group grades of evidence High certainty: We are very confident that the true effect lies close to that of the estimate of the effect Moderate certainty: We are moderately confident in the effect estimate: The true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different Low certainty: Our confidence in the effect estimate is limited: The true effect may be substantially different from the estimate of the effect Very low certainty: We have very little confidence in the effect estimate: The true effect is likely to be substantially different from the estimate of effect

¹ Downgraded one level due to serious risk of bias: unclear risk of bias in randomisation, high risk of bias in blinding of participants which is likely to affect patient reported outcome. High level of missing data.

² Downgraded two levels due to very serious imprecision: very small sample size (14 participants)

³ Downgraded two levels due to very serious imprecision: very small sample size (14 participants) for rare events.