Is it common to feel lightheaded during pregnancy?
It’s not uncommon to occasionally feel lightheaded or dizzy when you’re
pregnant. During this time, your cardiovascular system undergoes
dramatic changes: Your heart rate (pulse) goes up, your heart pumps
more blood per minute, and the amount of blood in your body expands by
an average of 40 to 45 percent. The capacity of your circulatory system
also increases as blood flows to your enlarging uterus and placenta.
In a normal pregnancy, your blood pressure goes down in the beginning,
reaching its lowest point in the middle of your pregnancy, and then
goes back to its normal level by the time you give birth. Most of the
time, your cardiovascular and nervous systems are able to adjust
appropriately to all these changes, but occasionally they don’t, which
can leave you feeling lightheaded or a bit dizzy. If you actually
faint, though, it could be a sign that something is wrong, and you
should call your practitioner.
No matter what the cause, lie down as soon as you feel lightheaded or
dizzy, to keep from falling and hurting yourself if you do faint. If
you’re in a place where it’s impossible to lie down, then sit and try
to put your head between your knees. And naturally, if you’re doing
anything that might put you or others at risk for injury, such as
driving, stop right away.
Lying on your left side will maximize
blood flow to your heart and thus to your brain, and will likely keep
you from actually fainting and probably relieve the sensation of
lightheadedness altogether. Here are some of the most common causes of
lightheadedness during pregnancy and advice for avoiding them:
• Standing up too fast.
When you stand up suddenly, blood pools in your lower extremities (your
feet and lower legs). (This pooling can also happen as a result of
prolonged standing or lying on your back in later pregnancy.) If your
body isn’t able to adjust when you stand up, not enough blood returns
to your heart from your legs and your blood pressure drops quickly,
which can leave you feeling faint. This can happen to people who aren’t
pregnant as well. If you sometimes feel faint when you stand up, avoid
springing up from your chair or bed. When you’re lying down, sit up
slowly and stay sitting a few minutes with your legs dangling over the
side of the bed. Then slowly rise from sitting to standing. If you’re
standing 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 blood flow in
your legs by compressing the inferior vena cava (the large vein that
returns blood from the lower half of the body back to the heart) and
the pelvic veins. Lying flat on your black 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,
though the left side works best. A pillow placed behind you or under
your hip can help you stay in a side-lying position (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 — and 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 with you so you can eat when you get hungry.
• Anemia. You may feel lightheaded if you’re anemic
because you have fewer red blood cells carrying oxygen to your brain
and other organs. Iron deficiency is the most common cause of anemia,
so be sure to take your prenatal vitamin, 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 hot, avoid hot crowded
places and wear clothing in layers so you can shed some as necessary.
Take warm instead of hot showers or baths, and try to keep the bathroom
• 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 sometimes prompt a “vasovagal” response
(this is the effect of your vagus nerve on your circulatory system): a
decrease in blood pressure and heart rate, leading to dizziness and
fainting. Dehydration, anxiety, or pain can also trigger this type of
fainting, sometimes called vasovagal syncope, and pregnant women are
again more vulnerable to it. It’s often preceded by lightheadedness and
other warning signs, such as a feeling of warmth, paleness, sweating,
nausea, yawning, and hyperventilation. Paying attention to these signs
and lying down immediately will often keep you from fainting.
Feeling lightheaded from heat, hunger, or getting up too fast can just
be a part of being pregnant. However, if the simple measures discussed
above don’t relieve the problem or if you have any concerns, don’t
hesitate to get help. Be sure to call your healthcare provider if you
have persistent lightheadedness or frequent bouts of dizziness, or if
your dizziness could be the result of a recent head injury.
Call right away if dizziness is accompanied by severe headaches,
blurred vision, impaired speech, palpitations, numbness or 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.
Also, early in pregnancy, abdominal pain accompanied by dizziness could
be a sign of ectopic pregnancy and needs immediate attention.