Ten Reasons to use the PrenaBelt®

Unlike the PrenaBelt®, which began clinical testing in 2014, pregnancy pillows and regular pillows have only recently undergone clinical testing. In 2024, Wilson et al. published the first clinical study of pregnancy pillows and regular pillows.[1] In a randomized cross-over study in 35 participants across 469 nights in the third trimester, they assessed the effectiveness of a pregnancy pillow in reducing the time spent sleeping on the back compared to regular pillows. The results? Participants actually spent more time sleeping on their back with the pregnancy pillow, 16% (approximately one hour), than they did with regular pillows, 13%! The researchers concluded that there is no evidence to suggest that the adoption of a pregnancy pillow designed to discourage sleeping on the back was effective in late pregnancy.

Below, is a side-by-side comparison of the percentage of time spent sleeping on the back with the PrenaBelt®, a sham-PrenaBelt (a belt that looks and feels like a PrenaBelt® but cannot provide positional therapy),[2] and regular pillows and a pregnancy pillow from Wilson et al.'s study.[1] From left to right, you can see that an average of 3.5% of the night is spent sleeping on the back with the PrenaBelt®. This is significantly lower than the percentage with the sham-PrenaBelt, regular pillows, and a pregnancy pillow, which are all around 15%. In response to Wilson et al.'s study, the PrenaBelt® team recently published a Letter to the Editor of the British Journal of Obstetrics & Gynaecology.[3]

When it comes to the health of a pregnancy, it is critical that any products a person uses are clinically tested and shown to be effective in multiple settings by multiple investigators and that the results are published in international medical journals with a rigorous peer-review process. After over a decade of painstaking work, the PrenaBelt® is the only device that meets this criteria. See our PrenaBelt® Research page for more information about the research that has been completed using the PrenaBelt®.

References:

1. Wilson DL, et al. A Position Modification Device for the Prevention of Supine Sleep During Pregnancy: A Randomised Crossover Trial. BJOG Int J Obstet Gynaecol, 2024.

2. Kember AJ, et al. Modifying maternal sleep position in the third trimester of pregnancy with positional therapy: a randomised pilot trial. BMJ Open, 2018.

3. Kember AJ, et al. Position Modification Devices to Prevent Supine Sleep During Pregnancy. BJOG Int J Obstet Gynaecol, 2025.

This means that it focuses on what matters most: the position of the pelvis and lower back. One of the most important factors affecting blood flow within a pregnant person and to the developing baby is the position of the person’s pelvis and lower back because this is the place where her major blood vessels can be compressed by the enlarged uterus.[1,2] This is the major flaw of all our competitors, which make the mistake of focusing on the position of the chest or by forcing the entire body to be in the same position as the pelvis and lower back. By ignoring the position of the pelvis and lower back, competitor products may be ineffective and make the user more uncomfortable, which further disturbs their sleep.

Reference:

1. Kember AJ, Anderson JL, House SC, Reuter DG, Goergen CJ and Hobson SR (2024), Impact of maternal posture on fetal physiology in human pregnancy: a narrative review. Front. Physiol. 15:1394707. doi: 10.3389/fphys.2024.1394707
2. Kember AJ, Anderson JL, Gorazd NE, House SC, Kerr KE, Torres Loza PA, Reuter DG, Hobson SR and Goergen CJ (2024), Maternal posture-physiology interactions in human pregnancy: a narrative review. Front. Physiol. 15:1370079. doi: 10.3389/fphys.2024.1370079

As previously noted, the blood flow within one's body and to one's uterus, placenta, and developing baby, is dependent on the position of the pelvis and lower back. By focusing on what matters most, the position of the pelvis and lower back, the PrenaBelt® offers more freedom, comfort, and support while sleeping. Also, who would have thought that one needed support while sleeping?! Most people only wear maternity support belts during the day; however, research has clearly implicated turning over in bed at night as one of two activities that consistently triggers low back pain from 5-7 months until the end of pregnancy.[1] Further, when flat on the back in the third trimester of pregnancy, compression of a major blood vessel (the "inferior vena cava") by the enlarged uterus can result in congestion of tiny blood vessels that drain important structures in the lower spinal cord, which is thought to provoke a nerve-based "achy" pain.[2-4] We were surprised when some PrenaBelt® users raved about reduced pain during the night with the PrenaBelt®, but now it makes perfect sense!

References:

1. Morino S, et al. Low back pain and causative movements in pregnancy: a prospective cohort study. BMC Musculoskelet Disord, 2017
2. Paksoy Y, Gormus N. Epidural venous plexus enlargements presenting with radiculopathy and back pain in patients with inferior vena cava obstruction or occlusion. Spine, 2004
3. Fast A, et al. Night backache in pregnancy. Hypothetical pathophysiological mechanisms. Am J Phys Med Rehabil, 1989.
4. Fast A, Hertz G. Nocturnal low back pain in pregnancy: polysomnographic correlates. Am J Reprod Immunol, 1992.

The PrenaBelt® is passive, not active. This means that it does not wake you from sleep. By capitalizing on humans' highly sophisticated and natural mechanism to avoid pressure points during sleep, the PrenaBelt® Luna is natural and does not impact sleep quality or quantity.[1,2] The other PrenaBelt® attachments altogether prevent, in a passive manner, the user's pelvis and low back from ending up in positions with suboptimal blood flow. Active positional therapy devices are not so. For example, one of our competitors uses vibration to alert the user she is on her back, which rudely awakes her from sleep; however, a recent meta-analysis [3] emphasized the need for more research into the deleterious effects of using vibrational stimulation during sleep,[4,5] which has been shown to increase blood pressure.[6] 

References:

1. Kember AJ, et al. Modifying maternal sleep position in the third trimester of pregnancy with positional therapy: a randomised pilot trial. BMJ Open, 2018.
2. Warland J, et al. Modifying Maternal Sleep Position in Late Pregnancy Through Positional Therapy: A Feasibility Study. J Clin Sleep Med, 2018.
3. Ravesloot MJL, et al. Efficacy of the new generation of devices for positional therapy for patients with positional obstructive sleep apnea: A systematic review of the literature and meta-Analysis. J Clin Sleep Med, 2017.
4. Arnberg PW, Bennerhult O, Eberhardt JL. Sleep disturbances caused by vibrations from heavy road traffic. Cit J Acoust Soc Am, 1990.
5. Smith MG, et al. Physiological effects of railway vibration and noise on sleep. J Acoust Soc Am, 2017.
6. Davies RJO, et al. Arterial blood pressure responses to graded transient arousal from sleep in normal humans. J Appl Physiol,1993.

The PrenaBelt® provides more than just positional therapy during sleep in late pregnancy — it also provides musculoskeletal support and thermal therapy to the lower back and buttocks for aches and pains in pregnancy. The PrenaBelt® can also be used during labour and birth (see our FAQ page) and for support after pregnancy — even if you’ve had a c-section.

Regular pillows can be compressed flat or shift during the night. Regular pillows may sometimes end up on the other side of the bed or on the floor without the user knowing. The PrenaBelt® solves this problem by staying on all night long and attaching a special pillow to the user, per se. Further, in late pregnancy, bathroom visits are common during the night. When returning to bed after using the bathroom, one must grope around in the dark to reconfigure her pillows to ensure she is positioned on them correctly, and by the time she does this, she is wide awake and may struggle to fall asleep again. Because the PrenaBelt® stays on all night long, it does not require adjustment or reconfiguration upon returning to bed.

Unlike pregnancy pillows, the PrenaBelt® permits intimacy, does not overheat, and does not take up a lot of space in the bed or in storage. Users can take the PrenaBelt® on their next road trip! Users can snuggle with their partner without having 20 pounds of pillow and 20 inches of separation in between! Pregnancy pillows are giant heat sinks, and once the user's body heat warms them up, they may find it more difficult to stay cool. When pregnancy is completed, users of the PrenaBelt® don’t need to worry about finding a space the size of a small couch to store the PrenaBelt®, and they can pack it away in the same box it arrived in!

The PrenaBelt® was created as a collaboration between hundreds of patients and dozens of healthcare professionals including physicians, nurses, midwives, and biomedical engineers. Since 2013, the PrenaBelt® design has undergone several rounds improvement based on the feedback we received from our users.

We are pioneers in sleep-in-pregnancy research. The team behind the PrenaBelt® was the first team in the world to complete interventional trials of positional therapy for sleep in late pregnancy.[1-4] Our team and collaborators have published extensively on sleeping position in pregnancy - so much that, pardon our self-promotion, our competitors don't bother to do their own research and, if they do cite any research, they just cite ours instead! 

The American Journal of Obstetrics and Gynecology (AJOG) is, arguably, the #1 OBGYN journal in the world. AJOG receives over 2,500 submissions per year, and has an an acceptance rate of about 12%. The PrenaBelt® team has published in this prestigious journal! Drawing on over a decade of experience in sleep-in-pregnancy research, our team provided important insight into the results of DeVore et al.[5] We first reviewed DeVore et al.'s results and then contextualized them vis à vis previous work of other research groups (including ours) and highlighted the corroborative nature of the evidence to date.[6]

We recently published a Letter to the Editor in the Journal of Clinical Sleep Medicine. In our article,[7]  we briefly reviewed the history of positional therapy in the fields of sleep medicine (introduced in the 1980's for position-dependent snoring and obstructive sleep apnea) and paediatric medicine (introduced in the 1990's for prevention of sudden infant death syndrome) and then highlight some of the recent work relating to positional therapy at the intersection of sleep, pregnancy, fetal growth, and stillbirth risk.

Furthermore, we are continuing to trail blaze the field of sleep-in-pregnancy research. We are leveraging computer vision (a branch of artificial intelligence and machine learning) to build sleeping posture detection models for non-contact, automated, sleeping posture detection and quantification in pregnancy,[8,9] which we intend to use to further our clinical research and understanding of maternal-fetal posture-physiology interactions. 

References:

1. Kember AJ, et al. Modifying maternal sleep position in the third trimester of pregnancy with positional therapy: a randomised pilot trial. BMJ Open, 2018.
2. Warland J, et al. Modifying Maternal Sleep Position in Late Pregnancy Through Positional Therapy: A Feasibility Study. J Clin Sleep Med, 2018.
3. Coleman J, et al. The Ghana PrenaBelt trial: a double-blind, sham-controlled, randomised clinical trial to evaluate the effect of maternal positional therapy during third-trimester sleep on birth weight. BMJ Open, 2019.
4. Coleman J, et al. Maternal positional therapy for fetal growth and customised birth weight centile benefit in a Bayesian reanalysis of a double-blind, sham-controlled, randomised clinical trial. BMJ Open, 2024.
5. DeVore GR, et al. Maternal rest improves growth in small-for-gestational-age fetuses (<10th percentile). Am J Obstet Gynecol, 2024.
6. Kember AJ, et al. Maternal rest improves growth in small-for-gestational-age fetuses (<10th percentile): a comment. Am J Obstet Gynecol, 2024.
7. Kember AJ, et al. A new frontier for positional therapy: obstetrics. J Clin Sleep Med, 2025.
8. Kember AJ, et al. Vision-based detection and quantification of maternal sleeping position in the third trimester of pregnancy in the home setting–Building the dataset and model. PLOS Digital Health, 2023.
9. Kember AJ, et al. Transitioning sleeping position detection in late pregnancy using computer vision from controlled to real-world settings: an observational study. Nature Sci Rep, 2024.

When a person purchases the PrenaBelt®, they are supporting the stillbirth cause and helping to eliminate these preventable tragedies in Canada and around the world. We will donate a portion of every PrenaBelt® purchase to advance stillbirth research, prevention, and advocacy.