| Methods |
Random ‐ method unstated
Single blind, participant was blind but other unclear
Crossover design
21 women randomised and analysed |
| Participants |
Inclusion: primary dysmenorrhoea, gynaecological exam to rule out pathology
Age: average 22, 15‐29 years
Location: Sweden |
| Interventions |
1. High‐frequency TENS ‐ duration 0.2 msec, freq 100 Hz
2. Low‐frequency TENS ‐ duration 0.2 msec, freq 2 Hz
3. Placebo TENS
Location: source of pain, lower back or abdomen
Duration: 45 min treatment once every month
On fourth month patient given treatment of choice and asked to compare with 500mg naproxen, fifth month asked to compare with 120mg verapamil (calcium‐channel blocker) |
| Outcomes |
Pain intensity VAS 0‐10
McGill pain questionnaire |
| Notes |
No difference in baseline scores |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Adequate sequence generation? |
Unclear risk |
"Randomly assigned to one of three groups", no further details. |
| Allocation concealment? |
Unclear risk |
Unclear. |
| Blinding?
All outcomes |
Unclear risk |
Single blind, participant was blind but other unclear. |
| Incomplete outcome data addressed?
All outcomes |
Low risk |
All 21 patients were analysed. |
| Free of selective reporting? |
Low risk |
All major and relevant outcomes reported on. |
