Comparison of the PainMatcher and the Visual Analogue Scale for assessment of labour pain following administered pain relief treatment.

OBJECTIVE

during childbirth, it is necessary to assess and monitor experienced pain and to evaluate the effect of pain relief treatment. The aim of this study was to compare the PainMatcher (PM) with the Visual Analogue Scale (VAS) for the assessment of labour pain and the effect of pain relief treatment.

DESIGN

randomised controlled trial.

SETTING

labour ward with approximately 2500 childbirths per year in western Sweden.

PARTICIPANTS

57 women with labour pain treated with acupuncture or sterile water injections scored their electrical pain threshold and pain intensity with the PM. Pain intensity was also assessed with the VAS. Electrical pain threshold and pain intensity were assessed immediately after a uterine contraction before and 30, 60, 90, 120, 150 and 180 minutes after treatment.

MEASUREMENTS AND FINDINGS

the results showed a weak correlation (r=0.13, p<0.05) between the pain intensity scores on the PM and the VAS. The PM detected changes (decrease) in pain intensity to a lower degree than the VAS. Surprisingly, in over 10% of sessions, women scored their pain intensity during a uterine contraction lower than their electrical pain threshold with the PM. However, electrical pain thresholds with the PM correlated well throughout all measurements.

CONCLUSIONS

the PM is a reliable tool for the assessment of electrical pain threshold; however, the VAS is more sensitive than the PM for recording changes in pain intensity when assessing the effects of treatment on labour pain.

IMPLICATIONS FOR PRACTICE

the PM and the VAS are not interchangeable in the case of labour pain, and there is still a need for research in this area to find a more suitable assessment instrument for the evaluation of labour pain.