What is it about?

Since 2011, six published research studies have shown a link between stillbirth, low birth weight, and sleeping on one's back during pregnancy. One way to keep people off their back while sleeping is by using "positional therapy". The earliest example of positional therapy is found in the late 18th century when soldiers in the American War of Independence were told to sleep with their rucksacks filled and strapped to their back in order to avoid rolling onto their back, snoring, and thereby disclosure of their position to the enemy. In more recent decades, positional therapy has been used to treat snoring and other breathing abnormalities during sleep. We designed a positional therapy device for pregnant women, called PrenaBelt, to help them minimize the time they spend on their back during sleep. Before testing the PrenaBelt in the real-world home setting across a long segment of pregnancy, we wanted to make sure it would work in the home setting, so in this study, we tested it in a group of 25 healthy, pregnant, Australian women (Adelaide) in the last three months of pregnancy in a similar manner in which we did in our Halifax study (https://link.growkudos.com/1kgnv8dqpds) except that the tests were completed in the comfort of the participants’ own homes rather than in a sleep laboratory. In Australia, we monitored the women’s sleep, breathing, and body position as well as their fetus’ heart rate. Each woman underwent the test on two different nights. Women were randomly assigned to use the PrenaBelt on the first night and nothing on the second night or the opposite order. On the night the participants used nothing, 48.3 minutes was spent sleeping on their back. This time was reduced 28.5 minutes on the night they used the PrenaBelt. We found a statistically significant reduction in the percentage of time spent sleeping on the back when using the PrenaBelt. On the PrenaBelt night, the women also had improved breathing and oxygen levels and their fetus had fewer abnormal heart rate changes compared to the night when they used nothing, and these differences were also statistically significant.

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Why is it important?

Each year, over two million babies die before or during birth (stillbirth). Each year, over twenty million babies are born with a low birth weight (LBW), which puts them at a twenty times higher risk of dying in the first year of life than babies with normal birth weight. Stillbirth (SB) and LBW are connected in some way. In high-income countries (HIC’s), SB rates have seen little or no improvement in the past two to three decades. Prevention strategies that target risk factors for SB could be key to making progress. The three most important risk factors for SB in HIC’s are maternal obesity, advanced maternal age, and maternal smoking; however, obesity and age are not realistically modifiable during the course of pregnancy. Therefore, strategies have been focused to target risk factors that are modifiable. Since 2011, six research studies have shown an association between SB, LBW, and sleeping on one’s back during late pregnancy. A recent study published in The Lancet confirmed these results and concluded that 6% of late SB could be avoided if every pregnant woman settled to sleep on her side from 28 weeks’ gestation until the end of the pregnancy. For comparison, quitting smoking in pregnancy can avoid between 4-7% of stillbirths. Therefore, this research, which is the first ever to study positional therapy during sleep in pregnancy in the home setting while simultaneously monitoring the fetus, is the first step in exploring a novel way of further reducing rates of SB and LBW worldwide.

Perspectives

I am first and foremost indebted to my colleague, mentor, and friend, Dr. Jane Warland, of the University of South Australia who was the Principal Investigator and First Author on this study. Under Dr. Warland's expert guidance, this study was an amazing success and was completed with little-to-no effort on my part with regard to the actual conduct of the trial. Of course, I am also grateful to Dr. Warland's team on the ground in Adelaide, some of which are co-authors - Drs. Dorrian, Phillips, and Morrison - and some of which are unnamed research assistants. I also received close supervision and warm mentorship from Dr. Louise O'Brien of the University of Michigan, USA. What I found so intriguing about this study were the unexpected benefits of the PrenaBelt, that is, the women's respiratory status and fetal heart rate tracings improved on the night they wore the PrenaBelt, which seems directly linked to spending less time on their back on that night. I am looking forward to watching developments in this emerging field.

Allan Kember
University of Toronto

The importance of this work cannot be understated, particularly if the use of a non-invasive external device demonstrates positive fetal and maternal outcomes. I very much look forward to future developments in this area of research.

Craig Phillips
University of South Australia

Read the Original

This page is a summary of: Modifying Maternal Sleep Position in Late Pregnancy Through Positional Therapy: A Feasibility Study, Journal of Clinical Sleep Medicine, August 2018, American Academy of Sleep Medicine (AASM),
DOI: 10.5664/jcsm.7280.
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