Introduction:
Good sleep is a fundamental component of overall health and well-being. It takes one-third of human existence, and unhealthy sleep can significantly impair two-thirds of life. An increasing amount of data supports that poor sleep, including sleep-disordered breathing, insomnia, and poor sleep quality, also negatively affects pregnancy outcomes.
In fact, over half of the significant risk factors causing stillbirths, such as gestational diabetes, maternal hypertension, and fetal growth restriction, are associated with pregnant women's sleep disruption. Recent studies suggest maternal sleep positions are a risk factor for stillbirth (the death of a baby during or just before the delivery).
What Is the Best Sleeping Position in the First and Second Trimesters?
During the first two trimesters, there is not much concern over the sleeping position as the size of a woman's uterus and the weight of the womb, including the fetus, placenta, and amniotic fluid, are not that much compared to the third trimester.
So It is also essential to educate which sleeping positions are not linked with poor pregnancy-related outcomes to reduce unnecessary sleep pattern limitations, worry, and anxiety among pregnant women, especially first-time pregnant women who might feel more anxious about the pregnancy.
In one such study, the researchers concluded that various sleeping positions during early and mid-pregnancy do not appear to impact the risk of complications throughout pregnancy and childbirth. This finding may help reassure many pregnant women, especially those who face difficulties while sleeping on their left side and pregnant woman with difficulties in controlling their position while asleep.
Hence, pregnant women can choose their preferred sleeping position during their early and mid-pregnancy without worrying about the negative impact on their baby in the womb.
What Is the Best Sleeping Position in the Third Trimester?
The best position during late pregnancy is sleeping on the left side. It has long been widely acknowledged that sleeping posture in late pregnancy can profoundly impact maternal hemodynamics (cardiovascular function including arterial pressure and cardiac output).
Studies have reported that in awake pregnant women, there is an apparent reduction in ejection fraction (it is a measure of the percentage of blood going out the heart every time it squeezes) and cardiac output (it is the amount of blood that the heart pumps in one minute) in the supine position (lying on the back) compared to the left lateral position. These changes can reduce the uteroplacental blood flow toward the fetus since the weight of the uterus presses on the inferior vena cava (a large blood vessel of the human body). Failure to prevent this compression can cause the maternal supine hypotensive syndrome. It may adversely impact the blood flow of the umbilical artery and gas exchange between the mother and fetus, which can consequently result in fetal heart rate decelerations (temporary but a typical decrease in the fetus's heart rate) and fetal growth restriction.
For over 60 years, it has become a standard of care to position a laboring pregnant woman in the left lateral tilt lying down to displace the weight of the uterus from the inferior vena cava for improvement in maternal hemodynamics. Despite this widely spread knowledge, little attention is paid to the maternal sleep position during late pregnancy. Given the known impacts of inferior vena cava compression, the possibility of a supine sleeping position increasing the risk of stillbirth is evident.
Many recent studies conducted in different countries on pregnant women of different ethnic origins also showed that supine sleep is independently linked to stillbirth. One of them found that the adverse effect of sleeping in the supine position on stillbirth was mediated through low birth weight. Moreover, these studies also suggested that if sleeping in a supine position plays a causal role in stillbirth, altering the sleeping position of pregnant women can decrease the occurrence of stillbirth by approximately 25 percent. However, one study recently demonstrated that of most pregnant women, approximately 80 percent spend some time in a supine sleeping posture, with the average time being around one-quarter of the night; therefore, supine sleep may represent a maternal stressor in case of unexplained late stillbirth.
What Are the Tips for Sleeping During Late Pregnancy?
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Several potential ways to reduce supine sleep and thus prevent the weight of the uterus from pressing on the important vessels include wedges of mattresses or pillows or other interventions.
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The tennis ball technique, sewing a patch with a tennis ball on the back of a night dress or a T-shirt, can prevent pregnant women from sleeping on their backs. If they move their back, the ball will result in pressure, waking the pregnant woman and encouraging them to move to their sides. It prevents supine position effectively, but compliance could be much higher. Some novel devices could also alert a pregnant woman during sleep, and they can then change their sleeping position.
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A lightweight backpack can also effectively prevent sleeping in a supine position if a pregnant woman places a baseball or a softball into it. When a pregnant woman tries to move their back during sleep, the discomfort from the ball causes them to shift over to their sides. This inexpensive method can make a difference for some pregnant women who struggle to stay in their lateral position throughout the night.
Conclusion:
Overall, extensive evidence suggests an increased risk of stillbirth during late pregnancy, after 28 weeks of pregnancy, and babies being born smaller for their gestational age is also associated with going to sleep in the supine position compared to going to sleep on their left-hand side. Hence, there is sufficient proof to advise pregnant women to avoid sleeping in a prone position, especially after 28 weeks of pregnancy.
However, the evidence also does not support an increased risk of stillbirth linked with sleeping on their right side, irrespective of the time, compared to sleeping on their left side. A pregnant woman can best control their sleeping position through conscious control. In addition, they can also use pillows or other props to aid that the left lateral position stays when sleeping.
