Introduction

The supine going-to-sleep position, when adopted after 28 weeks of pregnancy, is associated with giving birth to a small-for-gestational-age infant and late stillbirth.1,2While some professional associations, including the Royal College of Obstetricians and Gynaecologists, have incorporated this evidence into clinical practice guidelines,3the National Institute for Health and Care Excellence has pointed out that the evidence underlying this association is based on retrospective studies of self-reported going-to-sleep position, which may be limited by inaccuracies and recall bias4and does not account for the variability in sleeping position following sleep onset. As such, the potential impact of sleeping position from 28 weeks through birth on pregnancy outcomes has not yet been prospectively verified with objective measurements.
We previously built a computer vision model (“SLeeP AIDePt-1”; Sleep in Late Pregnancy: Artificial Intelligence for the Detection of Position) to automatically detect sleeping positions during pregnancy from video recordings. This model was built using a video dataset captured from pregnant individuals in their third trimester simulating a range of sleeping positions in a controlled setting.5However, real-world generalizability and ecological validity was severely limited because the video dataset only contained a single person in the bed, used thin and pattern-free bed sheets, did not allow any objects on the bed besides head pillows, did not include prone posture, and, overall, did not capture the complexities of real-world scenarios.
In an attempt to transition to real-world settings (the present study), our objective was to expand our controlled-setting dataset to include real-world videos and develop a new model (“SLeeP AIDePt-2”) for automated, unobtrusive, and non-contact detection and measurement of the sleeping position of a pregnant individual and their bed partner simultaneously overnight throughout the third trimester in the home setting. We aim to equip researchers with a tool employing this model to enable them to either confirm or disprove the associations between supine sleeping position in late pregnancy and adverse outcomes.