Adherence, tolerance and effectiveness of two different pelvic support belts as a treatment for pregnancy-related symphyseal pain - a pilot randomized trial

Abstract

Background: Pregnancy-related pubic symphysis pain is relatively common and can significantly interfere with daily activities. Physiotherapist-prescribed pelvic support belts are a treatment option, but little evidence exists to support their use. This pilot compared two pelvic belts to determine effectiveness (symptomatic relief), tolerance (comfort) and adherence (frequency, duration of use).

Methods: Unblinded, 2-arm, single-center, randomized (1:1) parallel-group trial. Twenty pregnant women recruited from the community (Dunedin, New Zealand), with physiotherapist-diagnosed symphyseal pain, were randomly allocated to wear either a flexible or rigid belt for three weeks. One author, not involved in data collection, randomized the allocation to trial group. The unblinded primary outcome was the Patient Specific Functional Scale (PSFS). Secondary outcomes were pain intensity during the preceding 24 hours and preceding week (visual analogue scale [VAS]), and disability (Modified Oswestry Disability Questionnaire [MODQ]). Duration of use (hours) was recorded daily by text messaging. Participants were assessed at baseline, by weekly phone interviews and at intervention completion (three weeks). To assess comfort, women wore the alternate belt in the fourth week.

Results: Twenty pregnant women (mean ± SD age, 29.4 ± 6.5 years; mean gestation at baseline, 30.8 ± 5.2 weeks) were randomized to treatment groups (flexible = 10, rigid =10) and all were included in analysis. When adjusted for baseline, PSFS scores were not significantly different between groups at follow up (mean difference -0.1; 95% CI: -2.5 to 2.3; p =0.94). Pain in the preceding 24 hours reached statistical significance in favor of the flexible belt (VAS, p = 0.049). Combining both groups' data, function and pain were significantly improved at three weeks (mean difference -2.3; 95% CI: 1.2 to 3.5; p< 0.001). Belts were worn for an average of 4.9 ± 2.9 hours per day; women preferred the flexible belt. No adverse events were reported.

Conclusion: These preliminary results suggest the flexible pelvic support belt may be more effective in reducing pain and is potentially better tolerated than a rigid belt. Based on these data, a larger trial is both feasible and clinically useful.

Trial registration: Australian New Zealand Clinical Trials Registry (ANZCTR) ACTRN12614000898651 , 25th August, 2014.

Figures

Figure 1

Flow diagram showing the study recruitment process.

Figure 2

The two types of pelvic support belts trialed in this study. (a) Wider, more flexible “Smiley” belt made of neoprene material (Smiley Belt, www.smileybelt.co.nz, Havelock North, New Zealand. (b) Thinner, more rigid belt made of nylon webbing and lined with foam (LC symphysis pubis belt, The Orthotic Center New Zealand Limited, Greenlane, Auckland, New Zealand). Both belts were worn in the “low” position [34] over the level of the pubic symphysis. Specific consent was given by the woman pictured, for these photographs to be published in this article.

Figure 3

Mean number of hours each participant wore the belt per day, over a 3-week period. The mean duration of daily use ranged from 0.8 ± 1.4 to 12.6 ± 1.9 hours. These data are based on the information returned by each participant in response to daily text messages.