Why can’t you sleep on your right side during pregnancy?

Normally people don't pay too much attention to sleep, and usually sleep in a way that makes them comfortable. When women are pregnant, sleeping posture is very important, especially in the middle and late stages of pregnancy, when the fetus will become larger. At this time, if the sleeping posture is incorrect, it will not only feel uncomfortable, but also be detrimental to the health of the fetus. Many people know that pregnant women should not sleep on their right side. The main reasons are as follows.

Why can’t you sleep on your right side during pregnancy?

The lying position of a pregnant woman has an impact on the development of both the pregnant woman herself and the fetus. When the pregnancy enters the middle stage, the uterus slowly rises from the pelvic cavity to the abdomen. After that, when lying on your back, the pregnant uterus can compress the abdominal aorta and inferior vena cava, affecting blood circulation; the later the pregnancy, the larger the uterus becomes, and the abdominal organs, especially the intestines, shift upward, causing the diaphragm to rise and the chest cavity volume to decrease. Therefore, some pregnant women may feel chest tightness and shortness of breath. The side-lying position may relieve the compression on the abdominal aorta and inferior vena cava and the impact on the diaphragm, thereby alleviating this symptom. Because the sigmoid colon is relatively fixed, the uterus deviates to the right in early pregnancy. When lying on the right side, the uterus, which is already tilted to the right, can be pushed further to the right due to gravity, compressing the liver in the right upper abdomen, causing discomfort. When lying on the left side, the uterus tilts to the left due to gravity, correcting the right-biased position of the uterus, making you feel more comfortable.

Experts consider side sleeping or SOS (pillow between belly and legs) to be the safest positions during pregnancy. Sleeping on your left side may have additional benefits, increasing the amount of blood and nutrients needed to meet the needs of the placenta and baby.

A study was conducted in New Zealand to determine whether a woman's sleeping position or other sleeping behaviors were associated with the risk of late fetal stillbirth. This case-control study showed that sleeping on your back increases the risk of stillbirth compared to sleeping on your left side. This result seems reasonable, but this study alone cannot prove that sleeping position affects the risk of stillbirth. Even so, the results still support the recommendation that pregnant women sleep on their left side.

Then everyone has a question, why lying on your back or on your right side is not suitable?

The reason why you cannot lie on your right side is: as the pregnancy progresses, the uterus continues to grow, and in the late pregnancy it almost occupies the entire abdominal cavity, which squeezes the adjacent tissues and organs and causes the uterus to rotate to the right to varying degrees, thereby putting the ligaments and mesentery protecting the uterus in a state of tension. The blood vessels in the mesentery that provide nutrients to the uterus are also pulled, which can affect the fetus's oxygen supply and easily cause chronic fetal hypoxia. In severe cases, it can cause fetal suffocation and death.

Actually, let me give you some more scientific information. Sleeping positions are very different in the three stages of pregnancy!

In the early stages of pregnancy (1-3 months), do whatever makes you feel comfortable!

Since the body does not change much, the fetus is still developing in the uterus and in the mother's pelvic cavity, and the direct pressure from external force will not be very heavy, so there is no need to over-emphasize sleeping position. As long as you feel comfortable, you can lie on your back or on your side.

In the second trimester (4-7 months), protecting your belly is key!

Your belly looks a bit big at this time, so try to restrain your extravagant sleeping posture. Be careful to avoid direct external force. If you have too much amniotic fluid or are pregnant with twins, you have to sleep on your side. If your legs feel heavy, you can lie flat and raise your legs with a pillow.

In the late pregnancy (8-10 months), sleeping on the left side is comfortable and safe!

Most people believe that the heart is on the left side, so it is best to sleep on the right side to reduce pressure on the heart. But for expectant mothers in late pregnancy, the opposite is true.