As your due date draws nearer, getting comfy is a real struggle.

A decent sleeping position can be hard to settle on when you're manoeuvring your bump but women in their third trimester have been warned not to sleep on their backs. New research has found that unborn babies' hearts were less active when their mothers slept on their backs rather than their sides. Thirty women who were between 34 and 38 weeks along were observed sleeping while their babies' heartbeats were monitored throughout the night. Researchers found that their heartbeats became quieter when women rolled from their sides to their backs. "Fetuses were only in an active state when the mother was on her left or right side," the study states. The study, carried out by researchers at New Zealand's University of Auckland is the first to monitor foetal heartbeats and mothers' sleeping positions at the same time, according to Science Daily. "In the situation where the baby may not be healthy, such as those with poor growth, the baby may not tolerate the effect of maternal back sleeping," said Professor Peter Stone, lead author on the study. "Our controlled study found that lying on your back can add extra stress to the baby, contributing to the risk of stillbirth. The risk is likely to be increased further in women with underlying conditions." The study was published in The Journal of Physiology - you can read more here.