There are a lot of things to be concerned about when you are pregnant. You worry about what you eat, how you exercise, what medicines you take, what chemicals you are exposed to, but just in time to make us even more stressed experts are now telling us we also need to be aware of how we sleep.
The sleep warning has been prompted by a New Zealand study that found women in the third trimester of their pregnancy who sleep on their back may place stress on their unborn baby which could increase the risk of stillbirth in certain cases.
Researchers from the University of Auckland monitored 29 healthy, pregnant women between 35 to 38 weeks and their fetuses while the women lay down in different positions, on their right or left side, and on their back for 30 minutes at a time.
The Journal of Physiology reports when the women lay on their backs or their right side, the fetuses were more likely to be in a sleep-like state that's associated with using less oxygen, compared to when the women lay on their left side. The fetus adapted to the mildly stressful situation by consuming less oxygen.
The researchers also studied the fetuses' heart rate variability, and found a link between those pregnant women in the study who lay on their back and a reduction in heart rate variability in the fetus. Researchers said that lower heart rate variability is known to precede fetal distress.
Researchers speculated in some cases, such as when the fetus is already deprived of adequate oxygen due to other factors, the fetus might not be able to adapt to the extra stress that is imposed by the mother lying on her back.
The researchers wrote in The Journal of Physiology "The supine position may be disadvantageous for fetal wellbeing and in compromised pregnancies, may be a sufficient stressor to contribute to fetal demise.”