Halifax PrenaBelt Trial

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.