What Causes Headaches during Pregnancy

Headaches are the commonest type of discomfort a pregnant woman would experience on top of the achy points of trouble or discomfort she would go through in coping up with the new responsibilities of pregnancy.

You can get headaches anytime during pregnancy, but it is commoner during the first and third trimesters. Health care professionals have identified various causes for these headaches.

What Causes Headaches during Pregnancy

Causes of Headaches During First Trimester 

The headaches which occur during the first trimester are mainly due to the gradual increase of blood volume after becoming pregnant (physiological hypervolemia) and sudden peaks of hormonal levels, taking place in order to facilitate the comfortable growing of the fetus inside the womb. However, these headaches can get more aggravated due to underlying factors like stress, vision problems and poor posture. These will probably subside towards the end of the first trimester, as a result of the settling of hormonal levels and your body getting adapted to the altered chemistry.

Other major causes of headaches during the first trimester include low blood sugar levels (hypoglycemia), sinus congestion (sinusitis), general fatigue, poor sleep, allergies (more vulnerable during pregnancy), hunger, withdrawal of caffeine from a woman who had continuously been using it, stress, overheating and dehydration.


Additionally, pregnant women who used to experience migraine from non-pregnant days are also at a high risk of developing frequent episodes of headaches during the first trimester due to the precipitation of etiological factors which are responsible for her migraine attacks (tension, lack of sleep). Furthermore, about 16% of women who never had migraines ever in their life, might experience it for the first time during pregnancy, probably due to causative agents crossing the corresponding threshold levels. Migraine headaches are characterized by moderate to severe throbbing pain on the head, typically on one side and usually last from 4 to 72 hours if left untreated. There can also be associative symptoms like nausea, vomiting, or increased sensitivity to light or loud noises.

It important to keep in mind that women should review her migraine medication after becoming pregnant since some drugs can be harmful to the fetus.

What Causes Headaches during Pregnancy

Causes of Headaches During Third Trimester 

Headaches, during the third trimester, are usually caused by poor posture due to the enlargement of the tummy and tension developed as a result of extra weight (fetus). This can also be caused by high blood pressure during pregnancy (pre-eclampsia) which should be promptly intervened due to several dangerous complications it can give rise to. Usually, preeclampsia will be diagnosed in your routine clinic visits; make sure to tell your doctor, if the headache is associated with changes in urine, vision changes and abdominal pain (liver and kidney abnormalities).

However, it is important to get medical advice if the headaches persist for more than four hours or if there are other symptoms such as fever, visual disturbances, sudden dramatic weight gain, or puffiness in the face or whole body.

As a concluding thought, most headaches occurring during pregnancy can be extremely unpleasant but at the same time, the majority of them will be harmless. But always keep in the mind to seek immediate medical advice if you tend to develop frequent episodes of headaches or severe explosive attacks since they can put your life as well as fetus’s life in danger.

Image Courtesy:

“Pregnant Woman” By Ken Hammond (USDA) – Pregnant (Public Domain) via Commons Wikimedia

About the Author: Embogama

Embogama is a passionate freelance writer for several years. Her areas of interest include general medicine, clinical medicine, health and fitness, Ayurveda medicine, psychology, counseling and piano music