The following is an excerpt From: Dawn A. Marcus, MD and Philip A. Bain, MD. The Woman’s Migraine Toolkit, 2011, DiaMedica (New York). You can purchase a copy of the book here.
What Is the Relationship of Hormones to Pregnancy, and How Does This Affect Headaches?
Pregnancy is another monumental milestone in a woman’s reproductive life and, not surprisingly, it has a huge impact on headaches. Once menses occur regularly, pregnancy is possible. When successful fertilization occurs, the fertilized egg is implanted in the uterus and a variety of hormones are produced, including human chorionic gonadotropin, or hCG, the substance that is measured by pregnancy tests. This surge in hormones is thought to be responsible for early pregnancy symptoms such as morning sickness. hCG stimulates the lining of the uterus to begin producing progesterone, which helps to provide nourishment for the developing embryo. The placenta is formed and connects the developing fetus to the uterus. Although the ovaries continue to produce estrogen early on, as pregnancy develops the placenta begins to produce estrogen as well. As the pregnancy progresses, estrogen, progesterone, and hCG levels increase significantly.
Estrogen levels rise dramatically during pregnancy and drop precipitously after delivery. The figure below shows the expected changes in estrogen levels during each trimester and during the postpartum period after delivery. Compared to first-trimester levels, estrogen increases sixfold by the third trimester and then drops to almost undetectable levels after delivery.
Many women find that headaches improve as estrogen levels surge during pregnancy. Improvement usually begins at the end of the first trimester. This tends to continue throughout the remainder of pregnancy, while estrogen levels stay high. When the baby is born, estrogen levels drop and headache protection is lost, causing headaches to begin again.
Sixty to seventy percent of women with migraine will have significant improvement in their headache patterns during the second and third trimesters.
Changes in estrogen levels during pregnancy and after delivery.
Expected changes in migraine activity with each trimester.
What If My Headaches Don’t Go Away During Pregnancy?
Although most women experience headache improvement with pregnancy, some do not. These women may require more intensive treatment during pregnancy. In general, headaches improve by the end of the first trimester. If you’re still having headaches at the time of your first obstetrical visit, they will likely continue during your pregnancy, and you should talk to your doctor about treatment options.
Talk to your doctor if you’re still having headaches when you go to your first visit with your obstetrician.
Some women actually develop their first migraine during pregnancy. Although most headaches during pregnancy are not caused by serious health problems, you should talk to your doctor whenever you develop new headaches, notice a change in your headache pattern or symptoms, or note new health problems. Some medical conditions that may cause headaches during pregnancy include:
- Preeclampsia/eclampsia (high blood pressure, edema, and other complications of pregnancy)
- Brain vascular diseases (such as strokes, aneurysms, dissections, and vascular malformations)
- Brain tumors (especially pituitary adenomas and meningiomas)
- Increased intracranial pressure not related to tumors (called pseudotumor or benign intracranial hypertension)
Migraine sufferers are at increased risk for developing increased blood pressure with preeclampsia/eclampsia and strokes, although the overall occurrence of these complications is quite small. You can help reduce your risk of high blood pressure and strokes by following these healthy lifestyle habits:
- Avoid nicotine.
- Exercise regularly.
- Maintain normal levels of cholesterol in your diet.
- Avoid excess weight gain.
Will Having Headaches Hurt the Baby?
Women with migraines are not at increased risk for having a baby with birth defects or giving birth prematurely. Even women having severe migraines during their pregnancy generally have their babies born at full term and of similar weight as headache-free moms.
What Happens After I Deliver?
Even if headaches improve during pregnancy, they typically return during the first 1—4 weeks after delivery. As already noted, estrogen and progesterone levels remain high during the third trimester. Delivery of the placenta after the baby is born causes a sudden drop in progesterone and estrogen. Estrogen levels will remain low for the next several months. The drop in progesterone helps to stimulate the production of breast milk.
In most cases, headaches return to the pre-pregnancy pattern after delivery. If you choose to breastfeed, you’re less likely to have your headache return during the first month after your baby is born.
As a side note, it is recommended that women who breastfeed not take estrogen-containing birth control pills because the estrogen can decrease milk production.
Excerpt From: Dawn A. Marcus, MD and Philip A. Bain, MD. The Woman’s Migraine Toolkit, 2011, DiaMedica (New York)