A: Your body goes through many adjustments when you're pregnant, and this includes your cardiovascular system (heart and blood vessels). Your heart rate increases and pumps out more blood each minute, your blood volume increases and, in most pregnancies, your blood vessels dilate slightly, leading to lower blood pressure.

Activities that exacerbate this decrease in blood pressure can cause lightheadedness by briefly decreasing the amount of blood flow to your head. Standing for prolonged periods of time, getting up too fast from lying or sitting, or becoming overheated can cause lightheadedness. Other causes include hypoglycemia (low blood sugar), iron-deficiency anemia and hyperventilation from anxiety or excessive exercise. Lying flat on your back during the second half of pregnancy is another common cause of wooziness.

If lightheadedness occurs, try lying down on your left side. This will maximize blood circulation. Think about the possible cause of your lightheadedness. If you got up too fast, try slowing down next time. When you arise from bed, sit up for a few minutes before slowly standing up. If extended periods of standing is the cause, improve your circulation by moving your legs or wearing support stockings. If you're not eating or drinking as well as you should, start eating frequent small meals throughout the day and make sure to drink eight to ten glasses of water a day. If you've been diagnosed with anemia, take iron supplements as prescribed. When you exercise, keep your movements to a pace where you could talk at the same time, or keep your heart rate under 140 beats per minute. And avoid prolonged hot baths or showers to avoid overheating.

If these suggestions don't help, or if you have frequent episodes of dizziness, don't hesitate to seek medical attention. Contact your health provider if you have had a recent head injury, if you actually fainted or if severe headaches, bleeding, changes in your speech or numbness accompany your lightheadedness.