- Mother’s-to-be’s sleeping position significantly affects their baby’s heart rate
- Foetuses’ hearts become less active when their mothers lie facing upwards
- The weight of the baby puts pressure on the blood vessels that supply the uterus
- Researchers recommend mothers don’t sleep on their back in late pregnancy
- The researchers analysed 29 healthy women who were 34-38 weeks pregnant
Pregnant women should sleep on their side in their last trimester, new research suggests.
Mothers-to-be’s sleeping positions have a significant effect on baby’s heart rates, a study found.
Foetuses’ hearts become less active when their mothers lie facing upwards as opposed to on their sides, the research adds.
Previous studies suggests sleeping on your back in late pregnancy puts excessive weight on the blood vessels that supply the uterus, resulting in reduced oxygen supply to the baby.
Lead author Professor Peter Stone from the University of Auckland, said: ‘We are suggesting that there is now sufficient evidence to recommend mothers avoid sleeping on their back in late pregnancy.’
Pregnant women should sleep on their side in their last trimester, new research suggests
How the research was carried out
The researchers analysed 29 healthy women who were between 34 and 38 weeks pregnant.
Their baby’s heart rates were continuously recorded overnight.
The study’s participants’ sleeping positions were determined via video recording.
Mothers’ sleeping positions impact babies’ heart rates
Results reveal pregnant women’s sleeping positions have a significant effect on their babies’ heart rate variability.
When such women sleep on their backs, their babies are less active than when they nod off on their sides.
If mothers-to-be change their position during sleep, for instance from lying on their left to their back, the baby quickly becomes ‘quieter’.
Professor Stone said: ‘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.
‘We are suggesting that there is now sufficient evidence to recommend mothers avoid sleeping on their back in late pregnancy, not only because of the epidemiological data but also because we have shown it has a clear effect on the baby.’
Previous research reveals mothers-to-be who lie flat facing upwards are at an increased risk of stillbirth. This is thought to be due to the weight of the baby putting pressure on the blood vessels that feed the uterus, which restricts the infant’s oxygen supply.
The findings were published in The Journal of Physiology.