Herbs for Pregnancy
Herbs for pregnancy can be divided into different groups depending upon the stage of pregnancy. Although red raspberry leaf tea has been suggested throughout pregnancy, it is not recommended during the first trimester if you are at all prone to miscarriage or show spotting. Generally you want to avoid herbs other than general nutritive herbs during the first trimester. Ginger can be used for nausea if you are careful - some women prefer pickled sushi ginger which is easier to digest and less heating. If you tend to "run hot" though you may want to stick to saltines and rice cakes to stave off morning sickness. And sea bands or a small magnet on the wrist can reduce the nausea altogether without herbs.
You do have some hormonal protection against illness, although that is not absolute. If you do develop a fever or flu, you might want to try half-hour baths with at least 2 cups of strong lemon balm (melissa) infusion before taking something internally through the digestive system. Echinacea is generally recognized as safe, but reserve it for real need. In general you need to balance the effects of a given illness or condition against possible risks: significant depression could be worse for a baby than St. John's wort, for example (although I'd try oatstraw, a nourishing nervine, first.) You want to avoid herbs with a strong downward energy suck as laxative herbs (although a mild bulking agent like ground flaxseeds or psillium seed is fine for constipation).
Curly or yellow dock tincture can help you assimilate the iron in your foods without binding you up like the iron in prenatal vitamins. Some authorities think it has too strong a downward action. I would only use it in a drop dosage- not more than a half teaspoon daily of tincture for iron or 1/2 cup of tea for occasional constipation. And it is probably good to err on the side of caution and to avoid it in the first trimester. I know many people who have used it throughout, but I'd rather be cautious. You do want to take sources of folic acid however, even if you avoid Prenatlins.
I also suggest that all herbs be taken in a form that you can taste - tinctures, teas or fresh and that they be avoided if you feel distaste. Some women develop a strong aversion to coffee, alcohol and vitamin supplements before they realize they are pregnant.
A professional herbalist with pregnancy expertise or herbal midwife may use herbs that you will find as "generally contraindicated in pregnancy" on lists. Some like black or blue cohosh can be used in a finely tuned manner to stop a miscarriage although their main use is to encourage labor. But you don't want to take them without professional direction as they could bring on a miscarriage in early stages of the pregnancy if not properly used. Many herbs like red rasberry are listed in some sources as having "oxytocic properties" with the implication that you should avoid them, but in reality are recommended to tone the uterus especially after the first trimester.
Chasteberry should be used only AFTER birth if hormone normalizing is needed. Things like aloe vera or comfrey should only be used externally.
Herbs that are safe during pregnancy or nursing
Adaptogens (help optimize your energies): borage flower, nettles
Analgesics (stop pain): valerian root, passionflower, lavender
Alteratives (cleanse the blood): nettles, red clover, alfalfa
Antidepressants (useful against depression): vervain leaf, melissa, lavender, borage, lemon verbena, vitex if due to hormonal imbalance
Antiemetics (keep you from throwing up): black horehound, rasberry leaf, melissa, chamomile, ginger
Antimicrobials (kill germs): garlic, corn silk, echinicea, shitake mushrooms, thyme herb (go easy and avoid the oil)
Antispasmodics (stop cramping): cramp bark, valerian root, chamomile
Astringents (tighten the tissues) : yarrow, witch hazel, periwinkle, catnip
Bitters (stimulate digestive juices): chicory root, dandelion, chamomile, burdock
Carminatives (help digestion): peppermint, fennel, anise, dill, ginger
Demulcents (slippery herbs good for helping pass things through):
marshmallow, slippery elm (also can be fed to infants)
Diuretics (make you pee): dandelion, corn silk
Galactogues (produce milk): fennel, anise, milk thistle seed, vervain leaf
Hepatics (liver support): dandelion, lemon juice
Nervines (for nervous mental states): oatstraw and oats, St. Johns wort, skullcap
Relaxants: chamomile, skullcap, lemon balm, catnip
Vulneraries (heal wounds): chamomile, plantain, St. Johns wort