A prospective 3-armed, participant-blinded, randomized controlled trial (interventions versus control group) will be performed to investigate the aims. The Template for Intervention Description and Replication (TIDieR) checklist and related guidelines will be used to report the study process [29,30]. The TIDieR checklist describes a standard way to document details carefully and allows authors to write interventions in their studies clearly [29]. The CONSORT-EHEALTH (Consolidated Standards of Reporting Trials of Electronic and Mobile Health Applications and onLine TeleHealth) checklist will be used to report data efficiently as an eHealth intervention trial [31].

Participants will be recruited from Isfahan University of Medical Sciences (IUMS), Isfahan, Iran.

The local ethical committee of IUMS approved the study protocol (IR.MUI.NUREMA.REC.1400.007). The study protocol was registered in the Iranian Registry of Clinical Trials on April 31, 2021 (IRCT20150210021034N11).

In total, 84 women with postpartum PPGP will be recruited. The optimal sample size was calculated on the basis of the results of a previous study [32]. The pain intensity for intervention groups was 58.2 (SD 13.93) and 64.4 (SD 13.96) at baseline, respectively [32]. We estimated a sample size of 25 in each study arm, which would yield 60% power (α=.1) and an effect size of 0.44 (Cohen d) in accordance with calculations performed using G*power software (Version 3.1, Universität Düsseldorf). We also considered an overall dropout rate of 10% (eg, lost to follow-up). Therefore, we aimed to recruit 84 participants (28 in each study arm).

Women with postpartum PPGP will be recruited through a simple (convenience) sampling method from the obstetric outpatient clinics of IUMS. The examiner will confirm the diagnosis with the presence of PPGP, and positive diagnostic tests include the following: ASLR, posterior pelvic pain provocation (also known as P4) test, Patric-Faber test, and Gaenslen’s test [33]. The inclusion criteria of the study are (1) primipara women who experienced natural delivery (one month before); (2) age between 18 and 45 years; (3) self-reported pregnancy-related PPGP; (4) a pain score of at least 40 out of 100 mm on the visual analog scale (VAS) [17]; and (5) a score of higher than 2 out of 5 on a 6-point Likert scale for perceived effort during the ASLR test [34]. The exclusion criteria were as follows: (1) the presence of lower back or pelvic pain before pregnancy; (2) history of any fracture in the pelvis and lower extremities; (3) history of spine, pelvis, and lower extremity surgery; (4) neurological diseases; (5) limb length discrepancy; (6) congenital anomaly in the spine, pelvis, and lower extremities; and (7) using any other conservative treatment for pain relief during the study, such as physiotherapy treatment methods. All eligible participants will provide informed consent and sign the consent form before inclusion in the trial. Participants will be free to withdraw at any time during the study.

Once participants are confirmed to be eligible, they will be randomly assigned with equal allocation at a 1:1:1 ratio (one control participant per treatment participant) to one of 3 groups: (A) pelvic (narrower) support (n=28), (B) lumbar (broader) support (n=28), and (C) control group (patient-education leaflet) (n=28). Block randomization will be used, with a block size of 6 to achieve balance in allocating participants to study arms [35]. The assessor will perform randomization with a Random Allocation Software (version 1.0) [36]. The nature of this study will not allow for masking of the assessor after assignment to interventions. Only participants will be masked to group assignment at the point of allocation.

Adverse events will be mentioned and recorded throughout the trial for participant safety. Information about adverse events, including the date and participant’s experience, will be summarized in tables. Information about participants who discontinued the study will be recorded. Furthermore, the reasons for dropout, such as COVID-19 symptoms, loss to follow-up, and sickness, will be reported.

There will be 3 different study arms. As intervention groups (A and B), the first and second arms will receive pelvic or lumbar supports for 4 weeks. As the control group (C), the third arm will only receive a patient education leaflet containing advice on strengthening exercises, comfortable positions, and other practical information. The outcomes include pain, effort score during the ASLR test, maximum isometric hip flexion force, maximum isometric hip external rotation force, maximum isometric trunk rotation force, and joint position reproduction (JPR) of hip abduction. The study outcomes will be measured at 4 time points: baseline (T1), immediately after the intervention (T2), 4 weeks after the interventions began (at this time, the intervention period is completed) (T3), and 1 week after discontinuing the interventions (T4) to evaluate the possible lasting effects of wearing supports. The study process is outlined in Figure 1.

This study will use 2 orthoses: pelvic (Group A) and lumbar (Group B) support (Teb Darman Co). Both orthoses are made of breathable textile material to comfort the participant. Orthoses can be worn on top of or under daytime clothes. The pelvic support will be an adjustable strap (10-15–cm width) fastened below the anterior superior iliac spine (Figure 2A). The lumbar support consists of a pelvic belt attached to the lumbar corset. Lumbar support has a 25-cm width anteriorly and extends from the xiphoid process to the pelvis. It has a 35-cm width posteriorly and extends down from the lower angle of the scapula to gluteal prominences (Figure 2B). Group C (control) will receive only a patient education leaflet containing advice on strengthening exercises, comfortable positions, and other practical information. Participants will be instructed to incorporate the regular activities into their daily routines and not use pain relief medication or other treatment during the following 5 weeks. Although we do not expect participants to experience any trial-related harm, they will be provided with a direct number to contact should they have any questions or queries and report any symptoms related to interventions or any discomfort experienced while wearing their orthoses.

All tests will be carried out with a certified orthotic practitioner. Table 1 outlines the outcome measures and shows how outcome measures will be measured at different time points throughout the study.

All data will be saved with identification codes to maintain confidentiality. Every effort will be made to follow up on all subjects by the examiner. All enrolled participants, including those who do not complete treatment, will be included in the analysis on the basis of the intention-to-treat principle. Missing data will be replaced by the mean imputation technique, in which the mean of the observed values will be calculated and reported. Descriptive statistics will present demographic characteristics and outcome measures for each intervention group. Multivariate ANOVA will be used to test between- and within-group differences. Data will be controlled for outliers and checked for the normality and homogeneity assumptions. Post hoc (Bonferroni) tests will be conducted to report pair-wise comparisons. SPSS (version 17.0; SPSS, Inc) will be used for statistical analysis, and statistical significance will be set at a P value of <.05.

It is generally accepted that rehabilitative modalities, including pelvic support, are suitable for PPGP [17]. Previous research has shown that lumbosacral orthosis effectively improved motor control and lumbopelvic function among patients with lower back pain [22]. The pathomechanics of lower back pain and PPGP are similar and include dysfunction of load transfer across the pelvis; hence, it has been hypothesized that wearing lumbar support could have beneficial effects for women with PPGP.

This study protocol will compare the impact of pelvic and lumbar supports on pain, disability, and hip repositioning in postpartum PPGP. The study results can be helpful for clinical decision-making. We anticipate that the study results will have significant implications for practitioners and specialists by increasing the scientific basis and contributing to the successful implementation of effective rehabilitation programs in clinical settings. Earlier studies have shown that both pelvic compression belts in pregnant women with PPGP [28] and lumbosacral orthosis in low back pain can significantly decrease pain [51] and improve proprioception [52], which can be explained by the biomechanical support provided [53] and proprioceptive impact of the orthosis [22]. At present, it is impossible to quantify which support is superior in reducing pain and improving proprioception and quality of life in women with PPGP. Suppose the lumbar support offers more favorable effects than the pelvic support in terms of pain reduction and improved sensorimotor outcomes. In that case, new orthotic interventions can be advised for women with postnatal PPGP.

This clinical study will evaluate repositioning in women with PPGP. For this repositioning, the JPR will be tested in a standing position. The upright position is a functionally relevant condition often occurring during daily activities. The hip abduction was selected since more precise scores for the proprioception test for the hip joint are assessed during this movement [49]. If pelvic and lumbar supports could affect the pain or load transfer at the SIJ, it could be reflected in the precision of JPR. The maximum force generation during trunk and external hip rotation is planned to quantify the possible effects of wearing the pelvic or lumbar support on the load transfer across the lumbopelvic area.

The strength of this study will be the investigation of the effectiveness of newly designed lumbar support for the management of PPGP. There may be limitations to this study. The inclusion and exclusion criteria set in this study can limit the generalizability of the results. Another limitation could be that some participants may be excluded because of incomplete trial time or not being interested in wearing the support.