Pregnant women who sleep on their backs more likely to suffer stillbirth

*There would be 3.7% decrease in condition if women slept on their sides as babies’ heart rates are less active when they lie facing up

Pregnant women who sleep on their backs during their third trimester are more than twice as likely to suffer a stillbirth, according to the largest study of its kind.

There would be a 3.7 per cent decrease in stillbirths if all pregnant women in the United Kingdom (UK) slept on their sides during their final trimester, the study estimates.

Previous research reveals babies’ heart rates are less active when their mothers sleep on their backs, which may be due to the weight of the foetuses putting pressure on blood vessels and therefore restricting the infants’ oxygen supply.

Lead author Professor Alexander Heazell from Tommy’s Stillbirth Research Centre at St Mary’s Hospital in Manchester, said: “Around 11 babies are stillborn every day in the UK. Parents want to know why their baby has died, whether it might happen again if they try for another baby and what they can do to avoid further stillbirth.”

Louise Silverton, director for midwifery at the Royal College of Midwives (RCM), added: “This addition to current knowledge is very welcome. It is a simple change that can make a difference.”

The researchers analysed 1,024 women from 41 maternity units across the UK. Of which, 291 suffered a stillbirth at 28 weeks or more into their pregnancy. The remaining 733 were still pregnant at the time of the study.

All of the study’s participants completed a questionnaire that asked about their sleeping practices before they became pregnant, as well as four weeks and the night before completing the questionnaire or suffering a stillbirth.

Results reveal pregnant women who sleep on their backs during their third trimester are 2.3 times more likely to suffer a stillbirth the following day compared to those who nod off on their side.

Stillbirths are also more likely to occur if women sleep less than 5.5 hours the night before, get up in the night to use the toilet or have a nap every day.

Sleeping on your back while pregnant does not influence a baby’s size or the length of a woman’s gestation.

The findings were published in the British Journal of Obstetrics and Gynaecology.