There are numerous herbs that are thought to be contraindicated during pregnancy, or that traditional herbalists consider potentially contraindicated during pregnancy. Studies are minimal, however. (See Low Dog 2005, Blumenthal, 2003, 1998, Weed 1986.) These herbs can be classified into five subgroups for an understanding of their potential effect on a pregnant woman:
1. Herbs used traditionally to stimulate menstruation (Table 2.19.4). Herbs that may stimulate the smooth muscle of the uterus may be risky during pregnancy, as they may cause a pregnancy loss.
2. Alkaloid-containing herbs (Table 2.19.5). Alkaloids are a diverse group of chemical plant constituents that have a wide range of pharmacological impacts on the body. Some alkaloids have been shown to be hepatotoxic and potentially carcinogenic. In some instances these compounds can be very potent, and they
Table 2.19.3 Herbs controversially used during pregnancy
Herb Usage Form and dosage
1. Ginger Nausea and vomiting, 250 mg four times a day or morning sickness maximum; ginger is also frequently used as a tea or infusion
Ginger is the only herb with reasonable evidence-based data regarding its benefit and safety during pregnancy. In several studies, it is estimated to be safe when used at doses of 250 mg four times a day or less (Blumenthal 2003, Low Dog 2005).
Three published placebo-controlled trials have addressed the safety and efficacy of ginger for morning sickness. In 1990, Fischer-Rasmussen reported 30 pregnant women, randomly assigned, who were admitted to the hospital before 20 weeks' gestation, and received either 250 mg of powdered ginger capsules or placebo four times a day over a 4-day period. No adverse effects on the pregnancy and outcome were noted.
Vutyavanicah (2001) conducted a randomized double-blind placebo-controlled study of 70 women with nausea of pregnancy with or without vomiting before the seventeenth week. Again, either 250 mg powdered ginger capsules or placebo four times a day was used. Good efficacy was reported, and no adverse effects were noted on pregnancy outcomes. A study in 2003 by Willetts, in a double-blind placebo-controlled trial, randomly assigned 120 women before the twentieth week of gestation who had experienced morning sickness daily for at least a week. These patients received either 125mg of ginger extract or placebo four times a day. Again, the efficacy was excellent, and outcomes were normal. Follow-up of the pregnancies revealed normal ranges of birth weight, gestational age, Apgar scores, and frequencies of congenital abnormalities when the study group infants were compared to the general population of infants born that year.
Surprisingly, the German Commission E (Blumenthal 1998) and the American Herbal Products Association (McGaffin 1997) contraindícate the use of ginger during pregnancy. This is definitely not supported by the popular data, popular
3. Evening primrose oil
Prevention and 300-400 mg three treatment of times daily urinary tract infection (Low Dog 2005, Blumenthal 2003)
Mastalgia, mood swings (Hibbeln 2002)
2.19 Herbs during pregnancy experience, or traditional-based evidence. Their advice appears to be based on two concerns. The first is that inhibition of thromboxane synthetase may affect testosterone binding in the fetus, although this usually happens at much higher doses than those practically used or used in the studies (Backon 1991). The second concern is in vitro evidence that gingerol and shogoal, isolated components of ginger, exhibit mutagenic activity in certain salmonella strains (Nagabhushan 1987). However, researchers have also found potential antimutagenlc compounds in ginger (Fudler1991). In that regard, however, a study of rats failed to find malformations in the offspring of animals administered 20 g/l or 50 g/l of ginger tea in their drinking water in early pregnancy.
Researchers at the Hospital For Sick Children in Toronto, Canada, studied 187 pregnant women who used some form of ginger In the first trimester (Portnoi 2003). In this small study, there were no increased risks in babies with congenital malformations compared to a control group.
With the vast number of women taking ginger during pregnancy, it is reasonable to assume that It is safe for women to use small amounts (up to 250 mg four times a day) of ginger during pregnancy. However, it is prudent to use ginger In moderation (Low Dog 2005, Blumenthal 2003, Muller 1991, Fudler 1991).
Although there is a long history of the safe use of cranberry during pregnancy there are no studies confirming this.
There are no known restrictions on the use of evening primrose oil during pregnancy (Chen 1999, Brown 1996, Harrobln 1992, 1991). No teratogenic effects have been seen, based on animal studies. According to The World
Table 2.19.3 (Continued) Herb Usage
Form and dosage
4. Aloe vera Topical use (only), Gel gel for burns (Low
Dog 2005, Blumenthal 2003)
5. Echinacea Prevention and 900 mg of dried treatment of upper root (or equivalent)
6. St John's Mild to moderate 300 mg three wort depression (Low times daily, of a
Dog 2005, standardized extract
Health Organization, pregnant and lactating women should obtain 5 percent of their total daily caloric intake from evening primrose, from EFA (essential fatty acids).
Although there is a long history of safe topical use during pregnancy, there are no studies showing its safety
Although there is a long history of safe use during pregnancy, there are very few studies (Gallo 2000, Mengs 1991) showing its safety. Early animal studies have failed to demonstrate evidence of mutagenicity or carcinogenicity after 4 weeks of ingestion of the expressed use of Echinacea at doses that far exceed normal human consumption. A prospective study of 206 pregnant women found no increased risk for fetal malformations when Echinacea was ingested during pregnancy, even during the first trimester (Gallo 2000). The authors of these studies suggest that gestational use of Echinacea during organogenesis is not associated with a detectable increased risk of malformations, but these studies did not have the statistical power or sufficient scientific rigor to assure this. The British Herbal Compendium, The German Commission E Monograph (Blumenthal 1998), and The American Herbal Products Association (McGaffin 1997) have listed the use of Echinacea as not contraindicated during pregnancy.
Although its safety in pregnancy has not been scientifically evaluated, the German Commission E (Blumenthal 2003, 1998) and the American Herbal Products Association (Blumenthal 2003, McGaffin 1997) state that St John's wort is not contraindicated. Its use in pregnant women is commonly reported. However, there have not been any adequate clinical trials using evidence-based
Tea/capsule - 2-3 g of crude herb at bedtime
2.19 Herbs during pregnancy principles that can absolutely reassure of safety of St John's wort for the pregnant or lactating woman. In one study in mice (Fudler 1991), maternal administration of 180 mg/kg of hypericum before and throughout gestation did not affect the long-term growth or physical maturation of exposed mouse offspring. In another study, no adverse effects were noted in the offspring of animals given 1.5g/kg per day of hypericum. No chromosomal abberations have been found on in vitro or animal testing. In one published case report, low levels of hyperforin were found in the breast milk of a woman who had been taking 300 mg three times a day of a standard extract of St John's wort while nursing (a standard dose). However, hyperforin and hypericin, compounds in St. John's wort, were undetectable in the baby's plasma. No adverse effects were noted in the mother or the infant (Rayburn 2001, Mills 2000, Okpanyi 1991). It should be noted that St John's wort induces CYP 3A4 and P-glycoprotein, which can result in decreased action of many drugs. Photosensitization has also been reported.
No contraindications have been found in the literature, including the German Commission E (Blumenthal 2003, McGaffinl 997) and the Botanical Safety Handbook (McGaffin 1997). Several articles and books support the use of valerian during pregnancy, and generally conclude that occasional use, for insomnia, is safe. Traditional clinical use supports its safety, and therapists use it for pregnant and lactating women. The World Health Organization (WHO) (Low Dog 2005), on the other hand, contraindicates the use of valerian during pregnancy and lactation as a general precaution, because its safety has not been established clinically - i.e. there are no clinical trials available using evidence-based medicine to prove its safety. In one study, valepotriates, the key constituent in valerian, was given orally for 30 days to pregnant rats, and there were no adverse findings in the pregnant rats or in their offspring. To date, there have been no studies of human pregnancies (Low Dog 1005, Blumenthal 1998, Tufik 1994).
Table 2.19.4 Herbs used traditionally to stimulate menstruation (not recommended during pregnancy)
Angelica Diuretic and diaphoretic
Celandine Loss of appetite; liver and gallbladder complaints
Goldenseal Dyspepsia, gastritis, diarrhea, menorrhagia
Shepherd's purse Arrhythmia, hypertension, hypotension, nosebleeds, PMS
Dong Quai Hormone imbalance, PMS, menopause
Motherwort Arrhythmia, hyperthyrold, flatulence, PMS
Southernwood Anxiety, depression
Slack Cohosh Menstrual irregularity, PMS, menopause
Mugwort Gastrointestinal complaints, sedative
Tansy Migraines, antihelminthic, neuralgia, rheumatism, loss of appetite
Blue Cohosh* Gynecologic disorders, dysmenorrhea, dyspareunia, menorrhagia, labor induction, 3ntispasmatic symptoms during labor
Feverfew Migraines; nausea and vomiting associated with migraines
Rue Menstrual disorders, contraception, abortifacient, anti-inflammatory
Yarrow Loss of appetite, dyspepsia, liver and gallbladder complaints
Nettle root Urinary tract Infections, kidney and bladder stones, rheumatism
Baldo Depression, stimulant
Andrographls Anxiety, gastritis
" Blue Cohosh has been used by some medical providers to Induce labor at the end of a pregnancy (Weed 1986)
have been isolated as medications or as the active ingredients in many pharmaceuticals and herbs.
3. Essential oils (Table 2.19.6). Essential oils are frequently used by patients in many situations. Some essential oils are potentially very dangerous during pregnancy when ingested. All essential oils
Table 2.19.5 Alkaloid-containing herbs (contraindicated during pregnancy) Herb Usage
Goldenseal Tansy Blood root Colt's foot
Hypertension, edema, menorrhagia, postpartum hemorrhage
Gastritis, gastrointestinal ulcers, external bruises, and blunt injuries
Constipation, loss of appetite, heartburn
Stimulation, increased performance, migraines, diarrhea, inflammation of the mouth/pharynx, weight loss
Dyspepsia, gastritis, diarrhea, and menorrhagia
Migraines, antihelminthic, neuralgia, rheumatism, loss of appetite
Expectorant, antipleque agent, mouthwash
Treatment and prevention of diseases of the respiratory tract
"Animal studies have suggested risks of reproductive and developmental toxicity (Joneja 1974, Dwornik 1967, Thiersch 1963).
"More than two cups per (fay of freshly brewed coffee (Christian 2001, Mills et at. 1993).
Table 2.19.6 Essential oils (contraindicated during pregnancy when taken orally)
Arbor vitae Liver deanse, loss of appetite, anxiety
Juniper Acne, liver problems, urinary tract infections, fluid retention
Pennyroyal Digestive disorders, colds, increased micturition
Nutmeg Stomach complaints
Catnip Colds, colic, migraines, nervous disorders, gynecologic disorders
Rosemary Loss of appetite, biood pressure problems, liver and gallbladder complaints, rheumatism
Depression, stimulant should be appropriately diluted when used, and none should be taken internally. In some instances, especially with external use, essential oils may be safe, but in general - especially during pregnancy - they are contraindicated.
4. Anthraquinone laxatives (Table 2.19.7). Anthraquinones are very potent compounds which can stimulate bowel peristalsis. They are frequently used as potential laxative agents. In pregnancy, overstimulation of the bowel or bladder has the potential to irritate/stimulate the uterus in some women, and may cause premature labor.
5. Herbs thought to have an effect on the hormonal system (Table 2.19.8). Herbs that may have an cffect on the hormonal system, and that have potential estrogen-like properties, give scientists cause for concern regarding the possible effects on the fetus.
Table 2.19.7 Anthraquinone laxatives (not recommended during pregnancy) Herb Usage
Alder buckthorn Constipation, anal fissures, hemorrhoids, diuretic
Cascara Constipation, anal fissures, hemorrhoids
Purging buckthorn Constipation, anal fissures, hemorrhoids
Senna Constipation, anal fissures, hemorrhoids
Table 2.19.8 Herbs with potential hormonal action (not recommended during pregnancy)
Ginseng Adaptogen, general tonic, fatigue licorice Gastric disorders, upper respiratory disorders, menorrhagia, menopause
Chasteberry (Vite*)" Menstrual disorders
5aw palmetto Benign prostatic hyperpiasia, menopause
Passion flower Nervousness and insomnia
Isoflavones PMS, menstrual disorders, menopause
Red clover Coughs, respiratory conditions, PMS, menopause
Hops Anxiety, insomnia
'Chasteberry is sometimes used by experienced practitioners to treat and/or prevent postpartum bleeding.
Recommendation. It is important to remember, and to remind patients, that it is critical to know the safety issues regarding particular herbs during pregnancy, and also critical to know the doses, stability, and purity of the product. ConsumerLab.com is an extremely helpful resource in this regard.
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