OBJECTIVE: To evaluate whether the percentage of time spent supine during sleep in the third trimester of pregnancy could be reduced using a positional therapy device (PrenaBelt) compared with a sham device.
DESIGN: A double-blind, randomized, sham-controlled, crossover pilot trial.
SETTING: Conducted between March 2016 and January 2017, at a single, tertiary-level center in Canada.
PARTICIPANTS: Twenty-three participants entered the study. Twenty participants completed the study. Participants were low-risk, singleton, third-trimester pregnant women aged 18 years and older with BMI <35 at the first antenatal appointment for the index pregnancy and without known fetal abnormalities, pregnancy complications, or medical conditions complicating sleep.
INTERVENTIONS: A two-night, polysomnography study in a sleep laboratory. Participants were randomized by computer-generated, one-to-one, simple randomization to receive either a the PrenaBelt or a sham-PrenaBelt on the 1st night and were crossed over to the alternate device on the 2nd night. Allocation concealment was by unmarked, security-tinted, sealed envelopes. Participants, the recruiter, and personnel involved in setting up, conducting, scoring, and interpreting the polysomnogram were blinded to allocation.
PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome was the percentage of time spent supine during sleep. Secondary outcomes included maternal sleep architecture, respiration, self-reported sleep position, and feedback.
RESULTS: The median percentage of sleep time supine was reduced from 16.4% on the sham night to 3.5% on the PrenaBelt night (pseudomedian=5.8, p=0.03). We were unable to demonstrate differences in sleep architecture or respiration. Participants underestimated the time they spent sleeping supine by 7.0%, and six (30%) participants indicated they would make changes to the PrenaBelt. There were no harms in this study.
CONCLUSIONS: This study demonstrates that the percentage of sleep time supine during late pregnancy can be significantly reduced via positional therapy.
TRIAL REGISTRATION: ClinicalTrials.gov NCT02377817
Supplementary File 1: R Code and output - Demographic Analysis
This is a stand alone report containing the code and output of an R script, which was generated by the "Compile Report" function in RStudio (R Statistical Software package (version 3.2.4 (2016-03-10))). This code summarizes the demographic, obstetric, and sleep behaviour of the participants (collected via a questionnaire completed by each participant on her first sleep test) and compares these data between all participants whose first sleep test was PrenaBelt (followed by sham-PrenaBelt on the second sleep test) versus all participants whose first sleep test was sham-PrenaBelt (followed by PrenaBelt on the second sleep test).
Code and output - Demographic Analysis.docx
Supplementary File 2: R Code and output - PSG Analysis
This is a stand alone report containing the code and output of an R script, which was generated by the "Compile Report" function in RStudio (R Statistical Software package (version 3.2.4 (2016-03-10))). This code processes the polysomnography (PSG) sleep reports in full, making within-participant (paired) comparisons and between-participant (unpaired) comparisons. The sleep reports were generated by Embla Sandman Elite sleep diagnostic software (Natus Medical Incorporated, Pleasanton, USA). The data in the PSG sleep reports was collected via Pro-Tech zRIP Durabelts (Philips Respironics, Murrysville, USA) for respiration, PT1 pressure transducers (BRAEBON Medical Corporation, Kanata, Canada) for airflow and snoring, electrodes (Natus Medical Incorporated, Pleasanton, USA) for ECG/EEG/EOG/EMG, and finger-tip pulse oximetry for peripheral blood oxygen saturation (SpO2) in accordance with the American Academy of Sleep Medicine 2014 guidelines. Audio and video data were also recorded and used in order to determine body position and snoring.
Code and output - PSG Analysis.docx
Supplementary File 3: R Code and output - Feedback Analysis
This is a stand alone report containing the code and output of an R script, which was generated by the "Compile Report" function in RStudio (R Statistical Software package (version 3.2.4 (2016-03-10))). This code processes the participants' feedback on the PrenaBelt (collected via a questionnaire completed by each participant after each sleep test). It summarizes these data, completes within-participant (paired) comparison of these data ("before/after"), and completes between-participants (unpaired) comparison of these data (bulk test for differences between all PrenaBelt sleep test nights versus all sham-PrenaBelt nights).
Code and output - Feedback Analysis.docx
Supplementary File 4: R Code and output - Self-Report Accuracy Analysis
This is a stand alone report containing the code and output of an R script, which was generated by the "Compile Report" function in RStudio (R Statistical Software package (version 3.2.4 (2016-03-10))). This code compares each participant's perception of her sleep behaviours (collected via a questionnaire completed by each participant after each sleep test) to her polysomnography-determined sleep behaviours (collected via audio and video and Embla Sandman Elite sleep diagnostic software (Natus Medical Incorporated, Pleasanton, USA)) in order to determine the ability of participants to accurately recall their sleep onset position, waking position, number of position changes during the night, and percentage of sleep time in each position.
Code and output - Self-Report Accuracy Analysis.docx
