Sleeping posture, behaviour, and environment in late pregnancy: A comprehensive analysis of a video-based, multi-night, in-home, level 3 sleep apnea study of pregnant participants and their bed partners

To characterize sleeping posture, behaviour, and environment in healthy pregnant participants and their bed partners across multiple nights in the home setting during late pregnancy, we completed a manual review of overnight video recordings from a four-night, in-home, level 3 sleep apnea study. Sleeping postures were scored according to a thirteen-posture classification system to determine the cumulative time per night spent in each sleeping posture. Additional aspects of sleeping posture, behaviour, and environment were also assessed. Forty-one pregnant participants and 36 bed partners completed the study, contributing 168 nights of video. Significant differences were found between the pregnant participants and bed partners in cumulative time spent in each posture as well as frequency and duration of episodes spent in each posture. Pregnancy status, side of the bed, and presence of a pregnancy pillow, bed partner, shared bed sheets, and pets in the sleeping space had various effects on the time spent in each posture. Pregnant participants spent more time in transition postures (going-to-sleep, waking-to-void, returning-to-bed, and waking-in-the-morning) than bed partners. There was a moderately positive correlation in posture changes between pregnant participants and their bed partners. Pets significantly increased the number of posture changes per night for both groups. Pregnant participants had more absences and time absent from bed. Sleep in late pregnancy is characterized by an increased frequency and duration of episodes spent in a restricted number of sleeping postures and is impacted by the sleep environment. Modifying the sleeping environment may improve comfort, minimize disturbances, and benefit sleep. Statement of SignificanceSubjectively-recalled supine going-to-sleep posture in late pregnancy is associated with stillbirth and fetal growth restriction. Sleeping posture, however, is dynamic, and few studies provide comprehensive analyses of sleeping posture in pregnancy using objective measurements. This novel study used a gold-standard objective measure of sleeping posture, was conducted across multiple nights in the participants own homes, and accounts for usual sleeping behaviours and environment by including the participants bed partner. A critical remaining knowledge gap is whether an individuals nightly sleeping posture varies significantly across the third trimester. Future work should use nightly, continuous, and objective methods to measure sleeping posture across the entire third trimester to bridge this gap and investigate the relationship between sleeping posture and pregnancy outcomes.