Feeling dizzy or faint is quite common, especially in early pregnancy. Pregnancy hormones cause your blood vessels to relax and widen. This is nature's way of improving the flow of blood to your baby, but has the side effect of slowing the return of venous blood. This causes your blood pressure to be lower than usual, so that if you stand for a long time or get up quickly from sitting or lying down the flow of blood to your brain may be temporarily reduced leading to dizziness or fainting.

Dizziness may also be caused by low blood sugar levels as your body adapts to changes in your metabolism. Getting too hot may make you feel even worse. Pregnant women tend to feel the heat more than other women!

Women who are anaemic or who have varicose veins may be more prone to dizzy spells than others.

In later pregnancy, you may feel dizzy if you lie flat on your back and the weight of the uterus presses on your vena cava (the large vein that carries blood from your lower body back to your heart). If your vena cava is compressed in this way, the flow of blood is restricted and you may quickly feel very giddy and faint. Even if you feel all right, your baby may notice the effects, and his heart rate may show signs of distress.

What can I do about it?

• Avoid standing for a long time. If you cannot avoid doing so, keep your legs and feet moving, to boost your circulation.
• Consider wearing firm support tights to ease varicose veins and help the return of blood from your legs.
• Get up slowly from sitting or lying down, or when you get out of a warm bath.
• Don’t go too long between meals. If necessary carry a few biscuits or some fruit with you so you can have a snack when you need it.
• Don’t lie flat on your back after about mid-pregnancy. If you are not comfortable sleeping on your side, push a small pillow behind your back to tilt you slightly to one side.

If you feel faint

• Sit or lie down, and lower your head
• Breathe deeply, and loosen any tight clothing
• Ask somebody to fan you or open a nearby window
• Rest for a while, then have something to eat

Dizziness alert

Occasionally, dizziness can be a symptom of shock following heavy loss of blood. If you feel weak, giddy or faint, have any vaginal bleeding, and/or pain in your abdomen, contact your midwife, doctor or maternity unit – whichever is quickest – straight away. This could be a sign of an ectopic pregnancy, a low-lying placenta, or a separating placenta.

Revised by babyworld midwife, Hannah Hulme Hunter November 2000.