Change positions slowly. Any movement that changes blood flow to your brain can cause a headache. Normally when you go from lying to sitting or sitting to standing your pulse and blood pressure quickly adjust to compensate for this change in gravity in order to pump enough blood to your brain. While pregnant your uterus seems to have "first dibs" on the blood supply so that the blood flow to your brain is momentarily reduced. As a result, you may feel dizzy, faint, or have a headache after jumping out of bed in the morning or rising from your easy chair at night. To help your baby-preoccupied cardiovascular system supply adequate blood to your brain, ease into position changes gradually.
Keep your blood sugar steady. Blood sugar drops trigger "hunger headaches" that can be prevented by frequent snacking on steady-energy foods, such as complex carbohydrates. Keep a purse-full of steady-energy snacks.
Search for fresh air. Stuffy, poorly ventilated, overheated, or pollution- filled rooms can cause sinus congestion and headaches. Avoid smoke-filled rooms. If you're attending a gathering in a crowded room, station yourself near a door so you can duck out frequently for some fresh air. In the winter months, when the heat is on, sit near a slightly opened window to counteract the drying effects of central heating. If you work in one of the newer, hermetically sealed office buildings, take your bathroom breaks near the lobby and step outside briefly for some outside air. If you cannot spend that much time on an elevator, consider buying an air ionizer. Many women find negatively charged ions vastly improve the air quality in their offices.