Headaches in pregnancy tend to occur most frequently in the first trimester. Hormone levels rise dramatically in early pregnancy, and can contribute to headaches. Changes in your blood circulation and blood volume during pregnancy can cause increased pressure on your blood vessels. This increase requires greater fluid intake to counteract dehydration, which can be another cause of headaches. Be sure to get at least 8 glasses of water a day.

Low blood sugar could also be the culprit, be sure to eat a healthy well balanced diet, with adequate protein and iron intakes. Avoid foods that can trigger a headache: like chocolate, MSG, cheese and spicy foods. Other possibilities are stress and anxiety or not getting enough rest. Try to take time each day to relax and make sure you get enough sleep.

Our data on September 4, 2008 shows that headaches are most common on 9 days past ovulation with 15.5% of pregnant women experiencing this symptom. Our data also shows that headaches is one of the top ten most common early signs of pregnancy. (View Top Ten Pregnancy Signs & Symptoms)

Click to view the full graph of Headaches – from Ovulation Day to 21 Days Past Ovulation.