When you are pregnant, it is not uncommon to feel lightheaded or dizzy occasionally. During pregnancy, your cardiovascular system is working overtime: Your heart rate goes up, your heart pumps more blood per minute, and the amount of blood in your body expands by 40 to 45 percent.  Your blood pressure is also undergoing changes from the norm, gradually decreasing in the beginning, rising again toward the middle, and returning to its regular level by the end of pregnancy.

Occasionally these changes can leave you feeling lightheaded or dizzy. Most of the time, your body is able to adjust to all these changes. If you feel uncontrollably dizzy or actually faint, it could be a sign that something is wrong, and you should call your practitioner.

Lie down as soon as you feel lightheaded or dizzy, so you won’t fall and hurt yourself if you do faint. If cannot lie down, sit and try to put your head between your knees. If you are driving or doing anything else that could cause a safety hazzard, pull over or stop right away.

Lying on your left side will maximize the blood flow to your heart — and thus to your brain. It will likely keep you from actually fainting and may relieve the sensation of lightheadedness altogether.

What is causing my dizziness?

Baby Center provides a list of some of the most common causes of lightheadedness during pregnancy and some advice on how to avoid them:

•  Standing up too fast When you sit, blood pools in your lower extremities (your feet and lower legs). If your body isn’t able to adjust when you stand up, not enough blood returns to your heart from your legs. As a result, your blood pressure drops quickly, which can leave you feeling faint. This can happen to people who aren’t pregnant as well.

To prevent lightheadedness, avoid springing up from your chair or bed. When you’re lying down, sit up slowly and stay sitting for a few minutes with your legs dangling over the side of the bed or couch. Then slowly rise from sitting to standing.

When you need to stand in one place for a long time, move your legs to promote circulation. Wearing support stockings can also help circulation in the lower half of your body.

•  Lying on your back In your second and third trimesters, your growing uterus can slow the circulation in your legs by compressing the inferior vena cava (the large vein that returns blood from the lower half of the body to the heart) and the pelvic veins.

Lying flat on your back can make this problem worse. In fact, about 8 percent of pregnant women in their second and third trimesters develop a condition called supine hypotensive syndrome: When they lie on their back, their heart rate increases, their blood pressure drops, and they feel anxious, lightheaded, and nauseated until they shift their position.

To avoid this problem, lie on your side instead of flat on your back. Either side is better than your back, although the left side is best. A pillow placed behind you or under your hip can help you stay on your side — or at least tilted enough to keep your uterus from compressing the vena cava.

•  Not enough food and drink When you don’t eat enough, you can end up with low blood sugar (hypoglycemia), which can make you feel dizzy or faint. This can happen much more easily when you’re pregnant.

Dehydration can have a similar affect. Make sure you stay well hydrated by drinking eight to ten glasses of water a day — more if you’re exercising or if it’s hot.

Try to keep your blood sugar from getting too low by eating small, frequent meals during the day instead of three large ones. Carry healthy snacks so you can eat when you get hungry.

•  Anemia If you’re anemic, you have fewer red blood cells to carry oxygen to your brain and other organs, which can leave you feeling lightheaded. Iron deficiency is the most common cause of anemia, so be sure to eat an iron-rich diet and take a prenatal vitamin with iron, especially in your second and third trimesters. If you become anemic, your caregiver will probably prescribe a separate iron supplement as well.

•  Getting overheated Spending time in a very hot room or taking a hot bath or shower can cause your blood vessels to dilate, lowering your blood pressure and making you woozy.

If you feel dizzy when you get too hot, avoid stuffy crowded places and dress in layers so you can shed clothes as necessary. Take warm showers or baths instead of hot ones, and try to keep the bathroom cool.

•  Hyperventilation Excessive exercise or anxiety can sometimes cause you to hyperventilate and feel faint. Although exercise can help your circulation, be careful not to overdo it if you’re feeling tired or not well. Start out slowly. If you start to feel lightheaded or dizzy while exercising, stop and lie down.

•  Vasovagal syncope Some people get dizzy when they strain to cough, pee, or have a bowel movement. These actions can prompt a vasovagal response (that is, an effect on your circulatory system by your vagus nerve) — a decrease in blood pressure and heart rate, leading to dizziness and fainting. (The word syncope means fainting.)

Dehydration, anxiety, and pain can also trigger this type of reaction, and pregnant women are more vulnerable to it. Lightheadedness and warning signs such as a feeling of warmth, paleness, sweating, nausea, yawning, and hyperventilation often precede vasovagal syncope. Pay attention to these signs and lie down immediately to help keep yourself from fainting.

When should I call the doctor?

Feeling lightheaded from heat, hunger, or getting up too fast may just be a part of being pregnant. But if the measures discussed above don’t relieve the problem or if you have any concerns, don’t hesitate to ask for help.

Be sure to call your healthcare provider in the following situations:

• You have persistent lightheadedness or frequent bouts of dizziness
• Your dizziness could be the result of a recent head injury.
• Dizziness is accompanied by severe headaches, blurred vision, impaired speech, palpitations, numbness, tingling, or bleeding, or if you actually faint. Any of these symptoms could be a sign of a more serious problem that could affect you or your baby.
• Abdominal pain accompanied by dizziness could be a sign of ectopic pregnancy, which requires immediate attention.

Photo from goodhealthpal.com