Nearly everyone has headaches sometimes. But having a headache in pregnancy is not fun. And managing headaches is even more tricky in the first trimester. This is a time when you should stay away from many medicines. Whether your headache is from tension or is a full-blown migraine, there are some things to know.

The exact cause of a headache isn't always clear. In the first trimester, changing hormone levels and blood volume may play a role. A dull, overall headache can come with stress, severe tiredness (fatigue), and eyestrain. Sinus headaches may be more likely because of the nasal congestion and runny nose that are common in early pregnancy. Hunger and low levels of blood sugar can set off headaches, too. People who suddenly stop their morning coffee and sodas may have caffeine withdrawal headaches. If you have nausea and vomiting in early pregnancy, you can become dehydrated. This can also bring on a headache.

Migraine headaches are a common type of headache in pregnancy. These painful, throbbing headaches are often felt on one side of the head. They are due to expansion of the blood vessels in the brain. They are sometimes accompanied by nausea, vomiting, and sensitivity to light. A small percentage of people also have an aura with the migraine. They see flashes of light or feel tingling in their arms and legs.

Here are steps you can take to help manage headaches:

• Stay away from any known headache triggers. These include allergens and certain foods, like monosodium glutamate (MSG), cured meats, and strong cheeses.
• Don't smoke during pregnancy. Also stay away from secondhand smoke.
• Try to eat well and drink plenty of fluids, especially if you are prone to morning sickness.
• Reduce your stress level. Try a massage or cold pack to help with tension headaches.
• If your headache is a migraine, rest in a cool, dark room with no noise. Try using warm or cold compresses or an ice pack.

But there is some good news. Most people have fewer headaches during pregnancy, especially after the first trimester. And those with a history of migraines often find there is improvement during pregnancy.

Contact your doctor now or seek immediate medical care if:

• You have a headache that is severe.
• You have a headache that doesn't go away.
• You have a headache with a fever.
• You have dizziness, blurred vision, or changes in your field of vision.

Headaches can sometimes be linked to blood pressure problems in pregnancy. If they are lasting or severe and happen after 20 weeks of pregnancy, let your doctor know. Strokes during pregnancy are rare. But migraines can increase your risk for them. If you have migraines, tell your doctor.