The increase in your blood volume, and thus the amount of blood being pumped around your body, is partially responsible for headaches that you might experience early on during pregnancy. This increased blood volume, coupled with dehydration and nausea, a lack of sleep, and low blood sugar levels, explains why you might be feeling a bit rough. These same symptoms often return at the end of your pregnancy, during the third trimester. Over the counter painkillers for your headaches are generally safe in pregnancy, when taken properly and in small amounts. But before you rush to your chemist, try some more natural remedies for your headaches in pregnancy as well.
I am convinced that dehydration is the main cause of headaches in pregnancy. You need a higher amount of fluids in pregnancy than you do normally, and you might be slightly dehydrated until your body gets used to this. At the same time, if morning sickness has been causing you to vomit, you will be losing fluids more quickly. I am not suggesting you drink gallons of water. But making sure you stay aware from caffeine, and that you drink water or tea every time you feel slightly thirsty could help a whole lot. Fatigue, which is inevitable in early pregnancy, is another major cause of headaches. If you are at all able, simply taking it easy or actually taking a nap when you feel like it could make your headaches disappear like snow before the sun! I realize that this is hard for most women, but taking care of yourself in early pregnancy is certainly very important.
Finally, eating small meals frequently and making sure you get lots of fibers and complex carbohydrates can make sure your blood sugar levels stay stable, which can reduce your headaches. Besides, a more frequent eating pattern, but not filling the stomach totally, can help you get relief from morning sickness, which in turn contributes to fewer headaches.