As always, be sure to check with your midwife or doctor. This reference was first written on the Pregnancy and Attachment Parenting list. Other references are given at the bottom of the page.
Most of this is from Healing Yourself during Pregnancy, by Joy Gardner.
Headaches are common during pregnancy due to hormonal changes.
Calcium. Calcium is good for pain. When taken alone, it tends to quiet
your nerves and ease your pain. But if you want more of a stimulating
effect, take 100mg of vitamin C with each dose of calcium. Usually
calcium comes in tablets of about 450mg. You may need to take one to
four tablets, one to four times per day, depending on how serious the
pain is. Note: If headaches get worse and more frequent, or it they
are worse at the upper back of your head, there is a possibility of high
blood pressure. If you have a fever of 102 degrees or more along with a
headache, with no other symptoms, this could also be dangerous. Consult
your health care provider.
Hops, Scullcap, and Catnip. These herbs can be takin as a tea or in
capsules for safe and effective relief. Bring 2 cups of water to a
boil. Remove from the heat. Add 1 teaspoon of each herb. Brew for 20
minutes. Reheat if desired, but do not boil. Drink one to two cups, as
needed. Store the unused portion in the refrigerator. Note: Any one of
these herbs, used alone, is also effective for tension headaches.
Peppermint Oil. Rub peppermint oil into your temples. Most people
experience a remarable easing of tension. Peppermint oil is available
in most drugstores. Some people use the Essential Balm which contains
peppermint oil. You can also drink peppermint tea, or combine it with
catnip, scullcap, and/or hops (see above recipe). Peppermint as a tea
is good for settling the stomach, which may be the cause of the
headache.