It is generally difficult to force yourself to sleep in any certain position when you are pregnant, but sleeping on the left side (as compared to the back or right side) has been shown to decrease the risk of stillbirths according to a study from New Zealand that was published in 2011. The authors conclude: "This is the first study to report maternal sleep related practices as risk factors for stillbirth, and these findings require urgent confirmation in further studies." The results should be interpreted with caution until more work is done, and a forceful campaign urging pregnant women to sleep on their left side is not yet warranted.
Though the American College of Obstetricians and Gynecologists, the professional organization of all Obstetricians and Gynecologists does not have a firm recommendation for the sleeping position of pregnant women, this study raises concerns about sleeping on your back during pregnancy.
In a chapter on difficulties of sleeping at night, ACOG suggests that women with sleeping problems should consider sleeping on their side …“with a pillow under the abdomen and another between the legs”, but that suggestion applies to women with sleeping problems, not necessarily as a precaution to improve pregnancy outcome.
The advice against sleeping on the back has probably it’s origin from a condition called ‘supine hypotension syndrome’ which is experienced by some women occasionally during pregnancy. The ‘supine hypotension syndrome’ usually occurs in the last trimester of pregnancy, though it can also happen earlier in pregnancy or post-partum. It is characterized by a feeling of dizziness and nausea in a woman lying on her back, occasionally forcing her to change position from the back to the side. In very rare exceptions, more likely on the operating room table and under anesthesia is it possible for the pregnant woman to lose consciousness.
The supine hypotension syndrome is also known as ‘vena cava syndrome’ because it is likely caused by the pressure of the enlarged uterus and the fetus on a large blood vessel, the inferior vena cava, which flows behind the uterus and through the liver towards the heart. This compression of the vein in turn can lead to less blood flowing back to the heart, and eventual decrease in blood pressure (hypotension).
Compression of this big vein can occur when the woman lies directly on her back, but it can also be observed in other positions such as in the pelvic tilt or sitting positions. The low blood pressure usually improves when you move from your back to your side. Because anesthesia may worsen the condition, pregnant women on the operating table are usually placed for precaution slightly tilted on their side with a wedge under their back.
If you do have problems sleeping during pregnancy here some recommendations for a good night’s sleep:
- Find a position that’s comfortable for you. Left side is better than right side or the back.
- Use pillows to ease the weight of the uterus, specifically in the last part of the pregnancy.
- Take a warm bath or shower at bedtime.
- Try not to rest or sleep too much during daytime.
- Exercise regularly, but not in the late afternoon or evening
- Don’t eat a heavy or spicy meal before bedtime. Eat 3-4 hours before going to bed. You may want to eat a small snack if you are hungry at bedtime.
- Don’t drink too much in the afternoon and empty your bladder shortly before you go to sleep
- Sleep at a comfortable temperature.
- Your mother was right: Having a cup of hot milk at bedtime eases your sleep and provides you with much needed calcium.
- And if all of this doesn’t work, try the ultimate sleep and relaxation technique: An orgasm at bedtime.