Can You Sleep on Your Back When Pregnant?

Pregnancy brings many changes to a woman’s body, including the need to adjust sleeping positions. As the belly grows larger, sleeping comfortably can become more of a challenge. One common question that pregnant women ask is whether it is safe to sleep on the back during pregnancy. There are some important factors to consider when determining the best sleeping positions during pregnancy.


Sleeping position is an important consideration for pregnant women. Getting adequate, high-quality sleep is vital during pregnancy to support the health of both mother and baby. However, as the body changes, women may find that their usual sleeping positions no longer work for them.

Many doctors advise pregnant women to sleep on their side rather than on the back. But why would side sleeping be recommended over back sleeping during pregnancy? Are there times when back sleeping might still be safe? This article will explore the pros and cons of back sleeping during pregnancy as well as provide tips to help pregnant women sleep more comfortably.

Changes to the Body During Pregnancy

In order to understand how sleeping position affects a pregnant woman, it is helpful to first review some of the physical changes that occur during pregnancy. A woman’s body goes through some remarkable changes to nurture and accommodate the growing baby.

Weight Gain and Belly Growth

It’s normal for women to gain weight during pregnancy as the baby grows and the body stores fat for breastfeeding. Weight gain often begins in the first trimester and continues steadily throughout the pregnancy[1]. The abdomen expands as the uterus enlarges to hold the developing baby. By full term, the uterus will have grown from the size of a pear to taking up most of the abdominal cavity[2]. This shifting body weight and enlarged belly can make finding a comfortable sleeping position more difficult.

Changes in Blood Flow

One of the most significant changes that occurs during pregnancy is increased blood circulation. A pregnant woman’s blood volume expands by 30-50% to supply adequate blood to the uterus and fetus[3]. The growing uterus puts pressure on the inferior vena cava, a major vein that carries deoxygenated blood from the lower body back to the heart. This can restrict blood return from the lower body when a pregnant woman lies flat on her back for extended periods[4].

Breast Changes

Hormonal changes during pregnancy prepare the breasts for lactation. The breasts become enlarged, heavier, and more sensitive. By the second trimester, the growing breasts and sensitive nipples can make side sleeping more comfortable than back sleeping for many women.

All of these physical changes to the body as pregnancy progresses influence the sleep positions that will feel most comfortable and provide health benefits.

Is It Safe to Sleep on Your Back While Pregnant?

Many health care providers recommend that pregnant women avoid sleeping on their backs, especially during the second and third trimesters[5][6]. But why is back sleeping considered unsafe by some practitioners? There are a few concerns with back sleeping during pregnancy.

Restricted Blood Flow

One of the most commonly cited risks of back sleeping during pregnancy is restricted blood flow. The weight of the uterus presses on the inferior vena cava when a pregnant woman lies on her back. This can decrease blood return from the lower body and potentially reduce the amount of blood and oxygen reaching the fetus.

However, some research indicates that restricted blood flow may not affect all women in the same way. One study found that blood flow was only reduced in a small percentage of pregnant women when lying flat on their backs. How prone a woman is to vena cava compression can depend on individual factors like the shape and position of her uterus.

Lower Blood Pressure

Lying flat on the back has also been associated with lower blood pressure in some pregnant women. When the uterus presses on the inferior vena cava, it can slow the return of blood to the heart. As more blood pools in the lower body, less blood reaches the heart. This reduces how efficiently the heart can pump blood, which may cause blood pressure to drop.

However, like vena cava compression, this does not appear to impact all pregnant women the same way. One study found no change in blood pressure among women who slept on their backs. A small drop in blood pressure while sleeping may not be cause for concern. But a significant drop could potentially deprive the baby of oxygen and nutrients.

Sleep Apnea

Sleep apnea, characterized by disrupted breathing during sleep, occurs more frequently in pregnant women. This is often attributed to weight gain, nasal congestion, and hormonal changes. Sleeping on the back can exacerbate sleep apnea and snoring as the tongue falls back into the throat, obstructing airflow. Sleep apnea has been associated with problems like high blood pressure and low birth weight. Sleeping on the side rather than the back may help keep airways open.

Digestive Issues

Many pregnant women experience heartburn, nausea, and other digestive issues. Sleeping on the back can aggravate these symptoms due to the pressure and position of the growing uterus. Heartburn is often worse when lying down flat. Sleeping propped up on the left side may alleviate digestive discomfort.

Stillbirth Concerns

A few studies have linked back sleeping later in pregnancy to a higher risk of stillbirth. One study found the risk of stillbirth was over twice as high for women who slept on their backs in the third trimester. However, there are some limitations to these studies. More evidence is needed to conclusively determine if back sleeping contributes to stillbirth risk.

While the risks associated with back sleeping during pregnancy have not been definitively proven, there are certainly reasons why side sleeping may be advantageous. If back sleeping is uncomfortable or disrupts sleep, it may be best avoided. But some women may be able to sleep on their backs safely, especially earlier in pregnancy.

When Can You Sleep on Your Back While Pregnant?

Many health providers recommend switching from back to side sleeping by the second trimester, around 16-28 weeks pregnant. But some women may be able to sleep comfortably on their backs for longer. Here are some factors to consider:

Stage of Pregnancy

The risks of back sleeping appear to be lower earlier in pregnancy when the uterus is smaller. Women who were back sleepers before pregnancy may be able to continue in the first trimester. By the second trimester, the growing uterus starts to compress major blood vessels more significantly when lying on the back.

Some women are able to sleep on their backs without issues well into the third trimester. But most women will become uncomfortable and switch to side sleeping as the belly size increases. If back sleeping is still comfortable past 16 weeks, consult a doctor about whether it’s safe to continue.

Individual Factors

The size and shape of the uterus and pelvis can impact how soon in pregnancy back sleeping becomes inadvisable. Women carrying multiples or those with an anterior placenta may need to stop back sleeping sooner. How prone a woman is to vena cava compression also varies. Doctors may recommend switching positions earlier if there are risk factors for blood flow restriction.

If back sleeping is causing noticeable symptoms like dizziness, nausea, shortness of breath or numbness in the limbs, it’s best to avoid the position. Pay attention to signals from the body and adjust accordingly.


Occasionally dozing off on the back is unlikely to cause problems. The risks appear greater when back sleeping is sustained for longer periods overnight when blood flow restriction could affect oxygen and nutrient delivery to the fetus.

Some doctors may approve back sleeping in the third trimester if women are able to periodically shift positions and avoid lying flat for long. But most recommend side sleeping as the safest choice as delivery approaches.

Tips for Sleeping Comfortably on Your Side During Pregnancy

Once back sleeping becomes uncomfortable or a doctor recommends avoiding it, there are ways make side sleeping more restful. Here are some tips for optimizing side sleeping during pregnancy:

Choose the Left Side

Sleeping on the left side is considered the optimal position during pregnancy. Lying on the left may improve blood flow and nutrient delivery to the placenta and fetus. Some possible advantages of left side sleeping include:

  • Takes pressure off the liver and kidneys
  • Promotes optimal blood flow through the inferior vena cava and aorta
  • May increase blood and nutrient flow through the placenta

Of course, either side is fine if left doesn’t feel best. Listen to what feels most natural for the body.

Use Pillows for Support

Using pillows for support and comfort is key to getting quality rest on the side. Some helpful ways to position pillows:

  • Place a pillow between the knees to take stress off the hips and pelvis
  • Use a body pillow to hug for comfort and support of the back
  • Put a pillow under the belly to take pressure off; a pillow under the back can also help
  • Elevate the head with a pillow to aid breathing and digestion
  • Position a pillow between the arms if needed for shoulder support

Experiment with pillow placement to discover what allows the spine to stay neutrally aligned and takes pressure off sensitive areas. Having multiple pillows of different sizes and shapes provides options.

Sleep at an Angle

Rather than lying directly on the side, sleeping at a 30-45 degree angle can feel more comfortable. Placing pillows under the back and head helps create an inclined position. This takes pressure off the abdomen and can minimize digestive issues like heartburn.

Avoid Twisting the Torso

When changing positions or getting in and out of bed, take care not to twist the torso. Keep the shoulders, hips, and knees aligned as much as possible. Twisting could potentially restrict blood flow from the inferior vena cava.

Consider Pregnancy Pillows

Special pregnancy pillows are shaped to follow the contours of the body in side sleeping positions. They provide cushioning support for the belly, back, hips and knees. Some styles completely wrap around the body. These pillows encourage proper alignment and may help pregnant women stay comfortably on their side.

Experimenting with different pillows and positions enables pregnant women to create a customized side sleeping setup tailored to their needs. This can provide the support and comfort required to get a good night’s rest.

Other Comfortable Sleeping Options During Pregnancy

In addition to side sleeping, some women may find these positions comfortable during pregnancy:

Propped Up

Sleeping propped up at an incline can take pressure off the abdomen and minimize heartburn, breathing issues, and swelling in the limbs. This can be achieved by using pillows to prop up the upper body and head while lying on either side. Some women may be able to sleep propped up on their back as well.

Recliner or Couch

Lounging in a reclined chair or on the couch with the back and legs elevated can be a comfortable way for pregnant women to rest and sleep. This position takes pressure off the back. Use pillows for extra support.

Hands and Knees

Some women report relief from back pain by sleeping on their hands and knees. This position helps align the pelvis and spine properly. Pillows can be placed under the head, chest and knees for cushioning. This position may also minimize vena cava compression.

Being flexible and willing to experiment with different positions enables women to find what works best for their changing bodies during pregnancy.

When to Seek Medical Advice About Sleeping Positions

It’s always a good idea for pregnant women to discuss sleep-related concerns with their doctor or midwife. Seek medical advice about sleeping positions if:

  • Back sleeping is still comfortable past 16 weeks pregnant
  • Back sleeping causes any worrisome symptoms like dizziness or numbness
  • Snoring or sleep apnea symptoms arise
  • Severe discomfort interferes with sleep
  • Significant heartburn, hip/back pain, or breathing issues occur when lying down

A doctor can help weigh the risks and benefits of different sleep positions for each patient’s unique circumstances. They may have suggestions for making sleep more comfortable overall.

The Bottom Line

There are good reasons why sleeping on the side is often recommended over back sleeping during pregnancy, particularly as the due date approaches. Side sleeping enhances blood flow and comfort as the belly grows. But some women may be able to safely sleep on their back longer, especially if they avoid staying in this position all night.

The most important thing is listening to the body’s signals and adjusting positions accordingly. Being flexible and using supportive pillows enables pregnant women to get the rest they need for their health and the health of their baby. With some adjustments, women can find comfortable sleeping positions throughout the journey of pregnancy.