The effect of music on the sensation of labor pain
is consistent with three previous small studies (Clark
et al., 1981; Hanser et al., 1983; Limprasirt, 1996).
Clark and colleagues found that music decreased sensation
pain during labor and delivery, but the effect
was not clear because of the small value of the t-test.
They did not measure the affective component of pain,
but reported that anxiety, measured only once by
questionnaire, was significantly lower in the music
group. Hanser and colleagues and Limprasirt found
that music decreased behavioral measures of labor
pain. This is the first study to demonstrate that music
reduced reported sensory pain and report an effect
size in a randomized study with an adequate sample. It
is the first to show that music slowed the escalation of
affective pain.
The results of the current study differed from
those of Kusollearjariya (1997) who found that neither
Thai classical music nor Thai folk music in Northeast
Thailand significantly reduced labor pain in women
(n 30 per group). However, the groups were not
randomly assigned. In addition, Thai music is high
pitched and tones are not sustained, and although
probably familiar, it may not have been relaxing to
participants.
There are several limitations to this study. First,
pain measured at four time points may have been a
burden to some women during the latter part of labor,
when increased unreliability of the VAS scales was
found. Approximately 10 participants marked their
VAS scales quickly, seemingly without much thought.
Second, the restriction to only five types of music also
may have had an effect on the choices of a few
women; the music that they selected may not have
helped as much as a more preferred selection. Third