Pregnancy Outcomes in Women Using HerbalTherapies

Timothy Johnsn and Lindi Sibeko

School of Dietetics and Human Nutrition, Macdonald Campus, McGill University, Ste. Anne de Bellevue,Quebec, Canada

Given that consumer interest in herbal therapies in NorthAmerica translates into spending of several billions ofdollars a year (Brevoort, 1996) one has to wonder ifcondemnation of use of all herbal products by pregnantwomen is realistic. Women use herbs despite disapprovalby their health care providers and consequently may notshare this vital aspect of their prenatal care. A moreconstructive approach by practitioners would be todevelop an informed understanding of the indicationsand contraindications of products available on themarket and assist in offering pregnant patients usefuland credible information. A less judgmental, informedpractitioner could encourage disclosure from patientsand in turn create a comfortable environment to discussthe appropriateness of herbal therapy.Some qualified health care practitioners do respond to

patient demand and interest by incorporating herbaltherapy in caring for their patients. A recent survey oflicensed and certified nurse-midwives in North Carolinaindicated that a large number recommended alternativetherapy in the care of pregnant women. The mostcommonly used modality was herbal therapy, whichwas prescribed for a variety of conditions including:nausea and vomiting, perinatal discomfort, lactationdisorder, postpartum depression, preterm labor, post-partum hemorrhage, labor analgesia, labor stimulation,and malpresentation (Allaire et al., 2000).

Benefits and Risks of Herbal Remedies

Traditional medicine is widespread globally and thealmost exclusive source of primary health care for 65% ofthe world’s population (Farnsworth, 1994). Herbalremedies have long-standing roles in treating disease,and in developing countries are widely taken by andadministered to women by traditional birth attendantsduring pregnancy. In the course of ethnopharmacologicalstudies in East Africa we have recorded plants employedroutinely during pregnancy and childbirth (Johns et al.,1990; Kokwaro and Johns, 1998). From an evolutionaryperspective herbal medicine is an adaptive humanbehavior (Johns, 1999), and plants with historicalimportance are the source of several modern pharma-ceuticals. Many herbs in widespread use have demon-strated pharmacological properties, and plants usedmedicinally as tonics or as diet supplements offerpotential benefits with nutrient, antioxidant and otheractivities. In light of these positive contributions to past

and present human well-being the point of view thatmedicinal herbs are categorically harmful is too extreme.Traditional medicines, like modern pharmaceuticals,

can do harm, but by and large legitimate traditionalhealers and qualified health care providers are sophis-ticated in avoiding and minimizing potential adverseeffects of the plants they use. The popular view thatbecause plants are ‘‘natural’’ they therefore accord healthis too sanguine.In reality, very little is known about the potential

adverse effects of plants in widespread use as dietarysupplements or natural health products in industrialsocieties, including those employed during pregnancy.The standard position of conventional health careproviders holds that until plants are proven to be safeduring pregnancy any such use should be avoided.Recognizing the historical importance of plant-basedmedicine, the fact that traditional medicine is culturallyimportant for many people in an increasingly multi-ethnic North American society and that few adverseeffects have been demonstrated, we take an alternatetact. Until negative effects of a plant are identified inpregnancy, health care providers and regulatory autho-rities should not deter mothers from consuming plantsthat long-standing practice points to as safe.The annual number of deaths from herbs in the United

States and Canada is low, no more than a few dozenand most of these are attributable to the abuse of ephedra(ma huang) (http://www.aapcc.org/annual.htm). Thesenumbers are small in relation to the rates of mortalityand side-effects associated with use of pharmaceuticals.In the Special Nutritionals Adverse Events MonitoringSystem (http://vm.cfsan.fda.gov/~dms/aems.html#search)there are only two questionable entries related topregnancy.

Measures of Pregnancy Outcomes

Statistics on the prevalence of consumption andpatterns of use in North America of specific herbs are

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Presented at the symposium entitled: "What Do We Know About theReproductive and Developmental Risks of Herbal and Alternate Reme-dies?" at the Public Affairs Symposium of the 40th Annual Meeting of theTeratology Society, June 24–28, 2000 in Palm Beach, Florida.nCorrespondence to: Dr. Timothy Johns, School of Dietetics and HumanNutrition, Macdonald Campus, McGill University, Ste. Anne de Bellevue,Quebec, H9X 3V9 Canada. E-mail: johns@macdonald.mcgill.caReceived 27 August 2003; Accepted 10 October 2003Published online in Wiley InterScience (www.interscience.wiley.com)DOI: 10.1002/bdrb.10052

generally lacking. Those data that have been reported(Eliason et al., 1997; Lyle et al., 1998) do not distinguishpregnant women from other users. Qualitative reportsand authoritative compilations, however, identify severalplants as being taken widely by expectant mothers. Thisstudy examines pregnancy outcomes associated with theplants commonly used in North America and Europe fora number of pregnancy-related conditions. With regardto the principle that plants that are used routinely aresafe until some evidence suggests otherwise, it considerscases where such evidence exists, but recognizes alsowhere the lack of evidence is equally notable. Measuresof pregnancy outcome that will be the basis forconsidering herbs used for several purposes duringpregnancy are: 1) abortion (miscarriage); 2) birth weight;3) malformations; 4) still vs. live birth; and 5) neonataldistress.

Herbs Without Apparent Adverse Effects

Among plants that are specifically used duringpregnancy, clear evidence of negative effects exists insome cases. For other plants advisory warnings areoverly cautious. For example, the major tonic takenduring pregnancy, red raspberry leaf, is consumed as atea by thousands of pregnant women each year but noadverse events related to its use have been reported.Nothing in its commonplace chemistry would indicate aneed for caution any different than for the majority ofplants food ingested during pregnancy. Nonetheless,Newall et al. (1996) place raspberry on their precau-tionary list because of its traditional reputation and areport on in vitro uterine stimulating activity. The lack ofcaution regarding raspberry by the German CommissionE (Blumenthal, 1998) or in the Botanical Safety Handbookof the American Herbal Products Association (McGuffinet al., 1997) would appear more in line with reality.Applying blanket advisories against uses of herbs

during pregnancy to a case such as raspberry, whateverthe evidence or lack of evidence for any benefit derivedfrom ingesting it, runs counter to the experience ofthousands of women that the plant is, at the very least,benign. To ‘‘cry wolf’’ in such cases undermines thecredibility of health care providers whose professionalguidance is more needed in relation to herbs with truepotential for harm.

Potential Adverse Effects During Pregnancy

Knowledge of the chemistry, pharmacology, terato-genicity, and toxicology of particular plants points topotential adverse effects in pregnancy and provides thebasis of justifiable cautionary warnings. Herbs withrecognized toxicity can harm mother and fetus. Pregnantwoman may ingest some of these for pre-pregnantconditions or conditions not directly related to pregnancy(e.g., St. John’s Wort for mild depression) (Grush et al.,1998) although others are among herbs specificallyemployed during pregnancy. Our focus is on the latter.Plants that should be avoided encompass well-known

hepatotoxins including those containing pyrrolizidinealkaloids and others such as germander, chaparral,European pennyroyal, and American pennyroyal. Oxy-toxic and uterine stimulating herbs that may potentiallyinduce spontaneous abortion include aloes, blue andblack cohosh, chamomiles, golden seal, American pen-

nyroyal, parsley, rosemary, rue, tansy, chaste tree, andcastor. American pennyroyal is a known abortifacient. Inthe case of common culinary herbs such as chamomiles,parsley, and rosemary it is important to distinguish atherapeutic dose from the lower amounts consumedmore commonly.Certain activities of plants may affect a proportion of

woman, in particular those with concurrent conditions,and as a result bias pregnancy outcome. Hypertensiveactivities that may add to the complication of pre-eclampsia is reported for a number of herbs that areencountered during pregnancy including capsicum, bluecohosh, those containing caffeine (including cola, mate,tea, and coffee), ginger, ginseng, licorice, and vervain(Newall et al., 1996). Similarly hyperglycemic activitythat might complicate conditions of gestational diabetesare found in ginseng and licorice. Use of coumarin-containing plants such as alfalfa, angelica, dong quai,aniseed, and German and Roman chamomiles is aconcern for those women suffering coagulation disordersduring pregnancy.Drug–herb interactions are another concern (Fugh-

Berman, 2000) and the need for awareness of complica-tions of this nature is no less important during pregnancythan in other contexts.Additionally, allergenic effects that are well-known

with certain plant taxa affect susceptible women. Speciesin the Compositae family, are characterized by potentiallyallergenic sesquiterpene lactones that make plants suchas German and Russian chamomiles, dandelion, andfeverfew problematic. Other examples of potentialallergenic herbs consumed during pregnancy are foundin members of the Umbelliferae family, specificallyangelica and aniseed.

Major Use of Herbs For Pregnancy-RelatedConditions

Tonics. In addition to raspberry, a number of plantsare used during pregnancy in a manner that can bedescribed as nutritional tonics. These plants includealfalfa, stinging nettle, parsley, comfrey, yellow dock root,peppermint, evening primrose oil (EPO), and flaxseed. Inaddition fish oil plays a similar role. Although specificbenefits of such plants may not be clearly identifiable, ingeneral these herbs can contribute essential vitamins andminerals and in the case of EPO and flaxseed, specificfatty acids. Comfrey contains pyrrolizidine alkaloids andalfalfa contains coumarins and phytoestrogens.Advisories against the use of parsley are based on its

uterine stimulant constituents, apiol and myristicin,although the normal use of the plant in food presentsno problem. Parsley seed and volatile oil should beavoided during pregnancy (Newall et al., 1996). Yellowdock root contains anthroquinones but in too smallamounts to likely cause harm (McGuffin et al., 1997).Stinging nettle, peppermint, EPO, flaxseed, and fish oilspresent no known risk during pregnancy.

Nausea and morning sickness. Herbs used bywomen to counter nausea associated with pregnancyinclude chamomiles, dandelion, goldenseal, raspberry,ginger, and peppermint. The first three herbs havepotential adverse effects, chamomile and dandelion arepossible allergens and golden seal is a uterine stimulant.Most monographs advise against the use of ginger,

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a caution related to a theoretical affect on testosterone-binding. This caution has been discounted (Kincheloe,1998) relative to ginger as a food and likely applies tosupplement use as well.

Prevent miscarriage. Herbs with a traditionalreputation as preventing miscarriage include wild yam,raspberry, partridge berry, false unicorn root, and lobelia.Evidence against the use of lobelia, a plant that containslobeline, an alkaloid similar pharmacology to nicotine,stands out against the presumed safety of the otherspecies.

Laxatives. In general women looking for naturalremedies for pregnancy associated constipation areadvised to ingest bulk laxatives or a modified diet.Stimulant laxatives, are on most lists of plants that arecontraindicated in pregnancy. Cautions are made againstthe use during pregnancy of each of cascara sagrada, aloeand senna, all plants that contain anthroquinones. In thecase of frangulin, a major anthroquinone in cascarasagrada, such opinions are fully justified based on itsteratogenic and uterine stimulating activity.The data for aloe are less clear. Experimental studies

with sennosides and senna laxatives, however, refuteseither teratogenic or uterine stimulant activities (Anon-ymous, 1992). Senna, therefore, is another case for whichcategorical condemnation is overstated certainly in thesecond and third trimesters, although the potential forelectrolyte loss or interactions with pharmaceuticalagents provide other rationales for caution.

Labor induction. Herbs are used by womenduring the late stages of pregnancy or are employed bymidwives to induce labour. The five most widely utilizedof these, black cohosh, blue cohosh, red raspberry leaf,castor oil, and EPO, are the subject of a recent survey ofthe practices and opinions of nurse-midwives in the USA(McFarlin et al., 1999). Raspberry and evening primroseoil are apparently safe. Castor oil is a labor inducer ofhistorical importance. Although cases of tumultuous andprecipitous labor have been reported, the plant is usedworldwide, including by traditional birth attendants inEast Africa (Kokwaro and Johns, 1998) where the root isthe labor stimulant of choice. In qualified hands castor isregarded as safe.This caveat of ‘‘in qualified hands’’ might also be made

for blue and black cohosh except that serious cases ofuntoward outcomes are associated with the use of theseplants (Gunn and Wright, 1996; Jones and Lawson, 1998).Both possess recognized uterine stimulant activity,attributable to caulosaponin in blue cohosh. Both containthe teratogen methycystine, although this is not a factorrelative to the manner in which these plants are normallyused in pregnancy. In the most clear case where use ofblue cohosh in the final month of pregnancy led tocongestive heart failure in a newborn infant, the motherwas taking three times the recommended dose.This illustrates a major concern with self-medicated

herbs, especially ones with a narrow therapeutic index.Too often those who turn to herbs succumb to themisconception that if a little is good, more must bebetter. Blue cohosh is clearly a plant that should beused with extreme caution. Any uses of herbs to inducelabor, if not throughout pregnancy, ideally involveexpert support and advice rather than unguidedself-administration.

Pregnancy Outcomes

Abortion. The effects of oxytoxic herbs on preg-nancy outcome are difficult to measure. Deliberateinduction of abortion is known. Although any contribu-tion of this group of herbs to unintended miscarriage isspeculative, their potential activity supports the cau-tionary warnings applied to them.

Birth weight. No published data support the directeffect of any herbal supplement on birth weight eitherpositively or adversely. The benefits of good nutrition arewell-known. The demonstration of a small dose-responseeffect of caffeine-containing beverages in reducing theweight of neonates (Bracken et al., 2003) suggests thatother plants, such as those with known toxic effects,consumed in sufficient quantities might act in similarways. Studies examining the effects of cannabis, a widelyused drug of abuse, on birth weight are equivocal(Mason and Lee, 1998), and even anecdotal evidence islacking to point toward effects of any herbal remedies.

Malformations. Other than the cases of cascarasagrada and blue cohosh, few teratogenic effects havebeen demonstrated for herbs or their constituents likelyto be consumed during pregnancy. It is true that fewherbs or their constituents have been subjects inreproductive studies. The best documented case of amalformation from herbal ingestion is neonatal andro-genization attributed to a contaminant (Awang, 1991).This case highlights the need in North America foreffective regulations governing proper labeling and goodmanufacturing practices relative to botanical medicines,a separate issue from that addressed in this article.Phytoestrogens contained in foods (e.g., soya) and

herbs (e.g., alfalfa) have been recognized as havingpositive roles in preventing breast and prostrate cancersand other conditions. Modification of endocrine-depen-dent cancer risk may begin in utero (Adlercreutz et al.,1999). A recent epidemiological study that points to anassociation between hypospadia and a vegetarian diet,particularly including soy milk (North and Golding,2000), underlies the reality that endocrine effects duringfetal development are multifaceted and poorly under-stood.

Stillbirths and neonatal distress. Attachment ofresponsibility for stillbirth to herbs is rare and notimmediately separated from circumstances leading toneonatal distress. The cases of blue cohosh cited aboveand another case where chamomile was used to inducelabor resulted in maternal anaphylaxis and fetal asphyxia(Jensen-Jarolim et al., 1998) demonstrate that toxicity tothe fetus or mother by herbs during late stages ofpregnancy and labor is a serious concern.

Conclusions

Herbs offer potential physiological and psycho-socialbenefits. Faced with the reality that patients do and willcontinue to use herbs for complicated reasons (Astin,1998), restrictive regulations or simplistic advisories areinappropriate and counter productive. The relativescarcity of adverse effects suggests that most herbs usedduring pregnancy are safe in general. Raspberry, EPO,ginger, peppermint, and senna provide good examples ofwhere categorical condemnations of herbs during preg-nancy are misguided. Cases of negative effects may be

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idiosyncratic and have complicated manifestations.Responses to them and derivation of lessons from themneed to be made in a comprehensive and thoughtfulmanner.Health care providers can neither stop or ignore the

use of herbs during pregnancy. Rather they shouldbecome informed about the actual properties of herbsused during pregnancy. In this way they will be betterprepared to advise on when and which herbs should betruly avoided, and on those that pregnant women cancontinue to use in a manner of their own choosing.

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