Halifax PrenaBelt Trial

Modifying Maternal Sleep Position in the Third Trimester of Pregnancy With Positional Therapy: A Randomized Pilot Trial

Grand Challenges Canada, Innovative Canadians for Change, Global Innovations for Reproductive Health and Life, Kaishin Chu Design, Nova Scotia Health Authority, University of Michigan, Harvard University

Back and right-sided sleeping position in pregnant women has recently emerged as a potential risk factor for low birthweight (LBW) and stillbirth (SB) in the medical literature. Assuming that sleep position in pregnant women is modifiable, the same literature has indicated that this risk factor is modifiable; however, there is no evidence that this risk factor is truly modifiable. The proposed link between back and right-sided sleeping position in a pregnant woman and LBW and SB of her baby is multifactorial; however, it ultimately implicates the woman's body position in causing compression of one of the large veins that brings blood back to her heart. This compression, along with other factors relating to the woman, her placenta, and her developing fetus, may result in decreased blood flow (nutrition and oxygen) to her developing baby, which, depending on the extent and duration, could result in LBW or SB of her baby. If the back sleeping position during pregnancy has a causative role in LBW and subsequently SB, the literature indicates that up to 17% of LBW and consequently 26% of SB could potentially be prevented by changing position to avoid back sleep. Note that 20 million LBW and 2.6 million SB occur each year worldwide. Positional therapy (PT) is a safe and effective intervention for preventing people who snore or people who's breathing pauses during sleep from sleeping on their back - a position that makes their condition worse. The most basic form of PT modifies a person's sleeping position by either: Preventing them from sleeping on their back through restricting their movement, or Rather than restricting movement, significantly reducing the amount of time they spend sleeping on their back by applying pressure points to their body while they are on their back, which eventually causes them to shift into a different position and avoid lying on their back. The purpose of this study is to evaluate the ability of a PT intervention to modify the position of pregnant women from their back and right side to their left side while they sleep in late pregnancy. This study will help determine whether this potential risk factor is modifiable by way of a PT intervention, and whether it is feasible to intervene to reduce or prevent back and right-sided position sleep in late pregnancy. Demonstrating that the sleeping position of pregnant women can be modified through use of a simple, inexpensive PT intervention may be one of the keys to achieving significant reductions in LBW and late SB rates in Canada and worldwide.

The utility of the PrenaBelt in modifying maternal sleeping position and the effect of the PrenaBelt on maternal respiratory and cardiovascular parameters during sleep and sleep staging in the third trimester of pregnancy will be evaluated via a two-night, randomized, cross-over, sham-controlled, triple-blind, sleep study in third trimester pregnant women. Two nights: one night with a positional therapy (PT) device and one night with sham-PT device to determine treatment effect on outcomes. Randomized: participants will be randomized to treatment order: sham-PT on first night, then PT on second night, or vice versa. This will avoid the potential impact of changes to sleep across the two nights resulting from familiarization with the equipment, which could bias the results. Cross-over: on the second night, each participant will be crossed over from PT to sham-PT (or vice versa, depending on randomization order) to allow each participant to act as her own control for comparison of treatment effect on outcomes. Sham-controlled: a sham-PT device that has the same fit and form of the PT device but without the ability of function (pressure points) will be used as a control. The purpose of a sham-PT device is to identify any specific benefit of one element of a PT device (e.g., fit or form) above and beyond all benefits that might be attributed to everything else about that device (e.g., function). Note that there is no established effective therapy for the population for the indication under study. Triple blind: participants, sleep technologists monitoring and scoring the sleep tests, and the specialized sleep physician reviewing and reporting the sleep test results will be blinded to the intervention received each night. Laboratory: conducting this study in a controlled lab setting will allow for continual, real time monitoring of various cardiovascular, respiratory, and sleep parameters of each participant by the sleep technologist. This contributes to a more controlled and safer study overall. Sleep test: body position, various cardiovascular and respiratory parameters, and sleep parameters will be continuously recorded while the participants are sleeping. Sleep lab procedures will be followed by the personnel conducting, scoring, reviewing, and reporting the sleep tests from participant preparation through discharge

Sleep, Pregnancy, Stillbirth, Infant, Low Birth Weight, Infant, Small for Gestational Age, Infant, Very Low Birth Weight, Fetal Growth Retardation, Fetal Hypoxia

positional therapy, tennis ball technique, sleep in pregnancy, supine, polysomnography, sleep position, supine position

Participants will be randomized to treatment order: sham PrenaBelt on first night, then PrenaBelt on second night, or vice versa. This will avoid the potential impact of changes to sleep across the two nights resulting from familiarization with the polysomnography equipment, which could bias the results.

Participants will be randomized to treatment order: sham PrenaBelt on first night, then PrenaBelt on second night, or vice versa. This will avoid the potential impact of changes to sleep across the two nights resulting from familiarization with the polysomnography equipment, which could bias the results.

The PrenaBelt is a belt-like, positional therapy (PT) device designed specifically for pregnant women. While the PrenaBelt does not prevent the user from lying on her back or right side during sleep, it is expected to significantly decrease the amount of time she spends in these two positions via the mechanism of PT. PT is a simple, non-invasive, inexpensive, long-established, safe, and effective intervention for preventing people with positional-dependent snoring or obstructive sleep apnea from sleeping on their back - a position that exacerbates their condition. The PrenaBelt is worn at the level of the waist. By virtue of its design and position on the user's body, the PrenaBelt affects subtle pressure points on the back and right side of the user when she lies on her back or right side, respectively, activating her body's natural mechanism to spontaneously reposition itself to relieve discomfort, thereby reducing the amount of time she remains on her back or right side.

The Sham PrenaBelt and PrenaBelt are the same device except the plastic balls are removed from the Sham PrenaBelt so it cannot provide pressure points.

This is a standard polysomnography measure of the amount of time the participant spent sleeping during the sleep test.

This is a standard polysomnography measure of the amount of time (in minutes) that it takes a participant to transition from full wakefulness to sleep.

This is a standard polysomnography measure of the percentage (%) of time the participant was asleep during the sleep test.

This is a standard polysomnography measure of the number of times the participant was aroused from a deeper stage of NREM sleep to a lighter stage, or from REM sleep toward wakefulness. This is reported as a 'total arousal index', which is an average of the number of arousals per hour, and is further classified as a spontaneous, periodic leg movement, or respiratory arousal index.

This is a standard polysomnography measure of the number of times the participant was spontaneously aroused from a deeper stage of NREM sleep to a lighter stage, or from REM sleep toward wakefulness. This is reported as an 'arousal index', which is an average of the number of arousals per hour.

This is a standard polysomnography measure of the number of times the participant was aroused from a deeper stage of NREM sleep to a lighter stage, or from REM sleep toward wakefulness due to periodic limb movements (PLMs). This is reported as an 'arousal index', which is an average of the number of arousals per hour.

This is a standard polysomnography measure of the number of times the participant was aroused from a deeper stage of NREM sleep to a lighter stage, or from REM sleep toward wakefulness due to respiratory events. This is reported as an 'arousal index', which is an average of the number of arousals per hour.

Apnea hypopnea index (AHI) is a standard polysomnography measure to indicate the severity of sleep apnea. AHI is the average number of apnea and hypopnea events per hour. Will be reported as a total AHI in units of 'events per hour'.

Respiratory Effort-Related Arousal (RERA) index is a standard polysomnography measure to indicate arousals from respiratory effort. Will be reported in units of 'arousals per hour'.

This is a standard polysomnography measure. Like the AHI, RDI reports on respiratory events during sleep, but unlike the AHI, it also includes respiratory-effort related arousals (RERAs). RERAs are arousals from sleep that do not technically meet the definitions of apneas or hypopneas, but do disrupt sleep. Will be reported as a total RDI as well as RDI while supine and RDI while non-supine.

SpO2 measured by fingertip pulse oximetry is a standard measure to indicate the oxygen saturation. Mean SpO2, Min SpO2, and Max SpO2 during Rapid Eye Movement (REM), and Non-REM (NREM) states.

This is a standard polysomnography measure of the presence of snoring via nasal cannula (pressure transducer) and by objective report of the research assistant (real-time audio feed).

Each participant will complete the PrenaBelt User Feedback Questionnaire. On a scale of 1 to 10, participant's level of satisfaction with the PrenaBelt. Note: 1 = extremely dissatisfied 5-6 = acceptable 10 = extremely satisfied

Each participant will complete the PrenaBelt User Feedback Questionnaire. On a scale of 1 to 10, participant's level of comfort while wearing and sleeping with the PrenaBelt. Note: 1 = extremely uncomfortable 5-6 = acceptable 10 = extremely comfortable

Each participant will complete the PrenaBelt User Feedback Questionnaire. On a scale of 1 to 10, participant's intention to use the PrenaBelt during a subsequent pregnancy if it was available to her. Note: 1 = participant would never use it again 5-6 = participant would consider using it again 10 = participant would certainly use it again

To determine the accuracy of self-reported sleep behaviours against the gold-standard, polysomnography. This is the sleep onset position (left, supine, right) per the participant's self report and is compared with the sleep onset position (left, supine, right) per the polysomnography data.

To determine the accuracy of self-reported sleep behaviours against the gold-standard, polysomnography. This is the participant's waking position (left, supine, right, prone) per the participant's self report and is compared with the waking position (left, supine, right, prone) per the polysomnography data.

To determine the accuracy of self-reported sleep behaviours against the gold-standard, polysomnography. This is the number of times the participant changed body position (e.g., supine to left side) per the participant's self report and is compared with the number of times the participant changed body position per the polysomnography data.

To determine the accuracy of self-reported sleep behaviours against the gold-standard, polysomnography. This is the percentage (%) of total sleep time in each position (left, supine, right, prone) per the participant's self report and is compared with the percentage (%) of total sleep time in each position (left, supine, right, prone) per the polysomnography data.

Inclusion Criteria: ≥18 years old low-risk singleton pregnancy in the last trimester of pregnancy (≥28 weeks of gestation) residing in the Halifax Regional Municipality Exclusion Criteria: BMI ≥ 35 at booking (first antenatal appointment for current pregnancy) pregnancy complicated by obstetric complications (hypertension [pre-eclampsia, gestational hypertension, chronic hypertension], diabetes [gestational or not], or intra-uterine growth restriction [<10th %ile for growth]) sleep complicated by medical conditions (known obstructive sleep apnea, known to get <4 hours of sleep per night due to insomnia, or musculoskeletal disorder that prevents sleeping on a certain side [e.g., arthritic shoulder]) multiple pregnancy known fetal abnormality non-English speaking and reading

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Kember AJ, Scott HM, O'Brien LM, Borazjani A, Butler MB, Wells JH, Isaac A, Chu K, Coleman J, Morrison DL. Modifying maternal sleep position in the third trimester of pregnancy with positional therapy: a randomised pilot trial. BMJ Open. 2018 Aug 29;8(8):e020256. doi: 10.1136/bmjopen-2017-020256.

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