Thomas 1995.

Methods	Not stated if random Blinding unclear Crossover design 31 women randomised, 29 analysed
Participants	Inclusion: primary dysmenorrhoea, previous ineffective treatment with NSAIDs, contraindications to NSAIDs, gynaecological exam to rule out pathology, women with no previous use of TENS Age: mean 30.2 (7.3) years Location: Sweden
Interventions	7 treatments ‐ participants split into two groups: TENS or acupuncture Duration: 20 min treatment, 7 days and 3 days prior to onset of menstruation every month Acupuncture treatments: different mode each month for 4 months then preferred treatment for 5th month Location: 5 points, bladder 32 (back, bilateral), abdomen CV4, spleen 9 and 6 (legs) 1. manual stimulation at insertion, every 5 min 2. low‐frequency electrical stimulation at 2 Hz to evoke muscle contractions 3. high‐frequency 100 Hz, intensity adjusted to comfort level 4. periosteal stimulation (for 30 sec) 3 or 4 times for each point TENS treatments: 3 different modes for 3 months, patients preferred treatment for 4th month, pulse duration 0.2 msec Location: Thoracic 10 to Lumbar 1 1. Low‐frequency TENS, 2 Hz 2. High‐frequency TENS, 100 Hz 3. Placebo TENS
Outcomes	Pain scale ‐ VAS Blood loss Nausea Hours of work lost Analgesics taken (no mention of type or dose) Subjective assessment
Notes	No information on the baseline similarities of the randomised groups
Risk of bias
Bias	Authors' judgement	Support for judgement
Adequate sequence generation?	Unclear risk	"randomised although serial order was maintained".
Allocation concealment?	Unclear risk	Unclear.
Blinding? All outcomes	Low risk	Participants were blinded.
Incomplete outcome data addressed? All outcomes	Low risk	All patients analysed.
Free of selective reporting?	Low risk	All relevant outcomes were reported.

OCP: oral contraceptive pill