Feeling dizzy, faint, or light-headed during pregnancy is common. In most cases, these symptoms are part of the normal changes that occur in a woman’s body during pregnancy. Occasionally the cause of dizziness during pregnancy may require treatment, especially if it is persistent or interferes with daily activity. Pregnant women should take care when they feel dizzy so as to avoid falling, and the best thing to do is to sit or lie down until the feeling has passed. Fainting should be reported to a healthcare professional immediately, especially if it is accompanied by other symptoms such as abdominal pain or bleeding.
Causes of Dizziness During Pregnancy
- Pregnancy hormones (progesterone): Early in pregnancy, a woman’s body starts producing more progesterone. Progesterone has the effect of lowering the blood pressure by causing the blood vessels to open. Blood vessels are more open during pregnancy to increase the blood flow throughout the body. A low blood pressure can cause pregnant women to feel faint, even as early as the first trimester. Standing up slowly from a sitting position can help prevent dizziness and fainting due to low blood pressure. When lying down, sitting up first for a minute or two before standing can also help avoid feeling light-headed. If you are pregnant during the hotter months, exercising or even a hot shower can contribute to this effect, and care should be taken to avoid fainting or falling while outside in the heat or when showering.
- Pressure on the inferior vena cava: If you are pregnant, it is best to lie on your side while sleeping, rather than on your back, and especially to lie on your left side. This is because in the second and third trimesters, the uterus can put pressure on the vein that runs from the lower body to the heart (the inferior vena cava). Sleeping on the back increases the pressure on this vein and reduces blood flow. Sleeping on the side takes some of this weight off the uterus, reducing the pressure on the inferior vena cava. Pillows can be placed behind the back or between the knees to help keep you in the left-sided position while you are sleeping. While sleeping, a pregnant woman may unknowingly shift so that she is on her back, which can cause a drop in blood pressure. Some women develop a condition called supine hypotensive syndrome, which is characterized by such symptoms as nausea, anxiety, and lightheadedness.
- Vasovagal syncope: A common cause of fainting episodes, vasovagal syncope is caused by a chemical imbalance. The vagus nerve is a cranial nerve that runs from the brain to the abdomen. Stimulating the vagus nerve releases a chemical that slows the heartbeat and dilates the blood vessels. When this happens the brain does not receive enough blood, and this can cause a pregnant woman to faint. Vasovagal syncope can be brought on by pain, stress, straining during urination or bowel movement, dehydration, or anemia. Symptoms of vasovagal syncope include nausea; feeling warm or lightheaded; sweating; become pale; and hyperventilating. This condition is more common in pregnant women. Sitting down and putting the head between the knees can help prevent fainting when the symptoms of vasovagal syncope begin.
- Hypoglycemia and dehydration: Women’s bodies undergo significant changes during pregnancy, including changes to metabolism — that is, how the body processes food. These changes may cause pregnant women to experience low blood sugar (hypoglycemia), especially if they are not eating enough. An episode of low blood sugar can cause a woman to feel dizzy or lightheaded, or even to faint. Eating frequent, healthy meals throughout the day can help prevent the blood sugar from dipping and spiking. Dehydration can also cause lightheadedness or dizziness during pregnancy. Not drinking enough water or engaging in excessive exercise can quickly lead to dehydration.
- Anemia: Anemia is a common condition in pregnant women. Anemia is the lack of enough red blood cells in the body, and it may be caused by a deficiency in iron, folic acid, vitamin B12, or other vitamins in the diet. Mild anemia is usually no cause for alarm, but more severe cases of anemia can have an effect on a pregnant woman and on her unborn baby. It is important for pregnant women to receive prenatal care and to be routinely tested for this condition. Eating a varied diet that includes food rich in iron, and taking prenatal vitamins that contain iron and folic acid can also help prevent or treat mild anemia.
Preventing Dizziness During Pregnancy
The best way to prevent dizziness during pregnancy depends on what is causing it. When pregnant women feel dizzy or faint, they should sit down right away, or lie down on their left side. Other measures that pregnant women can take to avoid dizziness include:
- Eating nutritious meals
- Eating frequently throughout the day
- Drinking enough water
- Avoiding becoming overheated
- Sleeping on the left side
- Standing up slowly
- Avoiding standing for long periods
- Taking a prenatal vitamin or other vitamin supplements (as directed by a healthcare professional)
- Avoiding stress and stressful situations
- Taking cool showers or baths
What to do When Feeling Dizzy
The most urgent concern when you feel dizzy is to avoid fainting and possibly falling. A fall may result in an injury. If you are experiencing the early warning signs of a fainting episode, such as feeling warm, sweating, becoming pale, or feeling nauseous, you should immediately sit down or lie down on your left side. Depending on the circumstances, you should also loosen tight clothing, put your head between your legs, or lie down and raise your feet up above your head by propping them up on pillows or the arm of a chair or couch.
When the dizziness has passed, the possible causes for the dizzy spell can be remedied. Having a drink of water or a snack can help if the dizzy spell was caused by not eating or drinking enough. If overheating is the cause of the lightheadedness, taking a rest from exertion and moving to a cooler area with circulating air may help.
Upon waking in the morning or after a nap, pregnant women should sit up in bed and wait a few minutes, with legs hanging over the side, before standing. Standing up should always be done slowly.
When to Seek Care for Dizziness During Pregnancy
In most cases, dizziness during pregnancy is not a cause for alarm; it is merely a result of the normal changes caused by pregnancy. But a pregnant woman who experiences regular bouts of dizziness should speak to her healthcare provider about possible causes and treatments. A fainting episode should be investigated right away by a healthcare provider, especially if there is a fall. In some cases, fainting or falling may be a medical emergency. A fall that results in an injury or a bump to the pregnant belly should also be reported to a healthcare provider immediately. Contact your healthcare provider or call 911 if dizziness or fainting is accompanied by bleeding, blurred vision, abdominal pain, chest pain, or shortness of breath.