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Abstract

The use of herbal medicines by pregnant women varies among different countries, ranging from 4.3% in Sweden to 69% in Russia. The aim of this narrative review is to evaluate the benefits and safety of common herbal medicines used during pregnancy. A systematic literature search (from 1995 to February 2018) was performed using a variety of electronic databases. The levels of evidence of the clinical studies were graded using the Oxford Centre for Evidence-Based Medicine levels of evidence guidelines. From the 736 articles retrieved, 69 articles were used for this review. Ginger has been investigated extensively and has been consistently found to decrease nausea and vomiting associated with pregnancy (Level 2). There is insufficient evidence concerning the efficacy of other herbal medicines such as garlic, cranberry and raspberry in pregnancy (Level 3–4). Much of the literature is based on case reports with limited pharmacodynamic/kinetic studies. There are no clear data on the adverse herb–drug interactions during anaesthesia. As the risks of these interactions are unknown, it would be prudent for anaesthetists to explicitly ask their patients about their use of herbal medicines before surgery and prior to labour and birth. The European Society of Anaesthesiology and American Society of Anesthesiologists recommend that patients cease taking herbal medicines two weeks before surgery.

Keywords

Herbs parturient anaesthesia herbal medicine

There is much diversity in the use and roles of traditional, complementary and alternative medicine as a result of cultural practices and beliefs. The consumption of herbal medicines has increased worldwide.^1–3 Many consumers believe herbal medicines are of “natural” origin and therefore are safer alternatives to conventional medicines.^1,2

Herbal medications have been associated with harmful effects as a result of direct toxicity, herb–drug interactions, toxic constituents, contamination or adulteration with toxic metals or even undisclosed conventional drugs (e.g. steroids, non-steroidal anti-inflammatory drugs (NSAIDs)).⁴ In a cross-sectional study of 947 patients in Israel, Levy et al. reported that an adverse event occurred in 3.7% of patients who consumed dietary and herbal supplements.⁵ In a cohort study of 601 general surgical patients consuming traditional Chinese herbal medicines (TCHM), Lee et al. reported that patients who had been prescribed TCHM were twice as likely to experience hypokalaemia and impaired haemostasis (as measured by prolonged International Normalized Ratio (INR) or activated partial thromboplastin time (aPTT)) preoperatively.⁶

Parturients are apprehensive about the potential adverse effects of conventional medicines consumed during pregnancy, and so they take herbal products instead because they are believed to be harmless.⁷ However, the belief of their efficacy and safety in pregnancy is not evidence-based.

The aim of this narrative review is to evaluate the evidence on the efficacy and adverse effects of the common herbs used in the peripartum period and perioperative anaesthetic considerations.

Search strategy

A systematic literature search was performed on MEDLINE, PubMed, CINAHL and AMED (Allied and Complementary Medicine Database) databases from 1995 to February 2018 using the following key words: herbs, herbal medicine and supplements, complementary medicine, alternative medicine, Chinese herbal medicine, Ayurvedic medicine, pregnancy, labour, obstetrics, and midwifery. The search was limited to articles published in the English language and human studies. Data from studies involving acupuncture, transcutaneous electrical nerve stimulation, massage therapy, reflexology, aromatherapy, hypnosis, vitamin supplements or animal and in vitro studies were excluded. The search results were imported into “Endnote”, a bibliographic management program, and duplicate items were removed. The bibliographies of the retrieved articles were examined for additional relevant articles. From a total of 736 articles retrieved, 69 articles were included in this review. The levels of evidence of the clinical studies were graded using the Oxford Centre for Evidence-Based Medicine levels of evidence guidelines⁸ (Table 1).

Table 1.

Levels of evidence and grades of recommendation according to Oxford Centre for Evidence-Based Medicine 2011.

Level of evidence
1	Systematic review of all RCTs or n = 1 RCT
2	At least one randomized trial or observational study with dramatic effect
3	Non-randomized controlled cohort/follow-up study (observational)
4	Case-series, case-control studies or historically controlled studies
5	Mechanism-based reasoning (expert opinion, physiology, animal or laboratory-based studies)
Grades of recommendation
A	Consistent with level 1 studies
B	Consistent with level 2 or 3 studies or extrapolation from level 1 studies
C	Level 4 studies or extrapolation from level 2 to 3 studies
D	Level 5 evidence or inconsistent/nonconclusive studies of any level

RCT: randomized controlled trials.

Prevalence

The prevalence of the consumption of herbal medicines by pregnant women ranged from 4.3% in Sweden up to 69% in Russia.⁹ The prevalence was 52%–58% in Australia,¹⁰ 40%–48% in Norway and Italy,^11–13 6%–9% in Canada and USA,^14,15 58% in Malaysia¹⁶ and 43%–45% in China.¹⁷ Several surveys in Western countries have reported that consumption of herbal products was most frequent in parturients in the 41- to 50-year age group, and with higher education and income levels.^18,19 In contrast, there is an inverse association between income and herbal consumption in China and Hong Kong.¹⁷ This is attributed to the lower cost of herbal medicines in these countries making them more affordable to mothers with low family income. Other factors associated with consumption of herbal products include habitual or previous use of complementary medicine, primiparity, non-smoking and the desire for a natural birth.²⁰

In a survey in the United Kingdom, almost half of pregnant women were prescribed conventional medicines and almost half of these patients used herbal medicines. This raises concerns of potential drug–herb interactions. In early pregnancy, the herbal medicines most commonly used were ginger (35.6%), chamomile (23.2%) and raspberry (20.5%), whereas in late pregnancy the herbal medicines used were raspberry (42.5%), cranberry (26.7%), ginger (23.7%) and chamomile (11.8%). More than half of the parturients used more than one herbal product.²¹ In Eastern countries, the types of herbs are more varied; Angelica sinensis (dong quai) is most popular among Chinese mothers as it ‘enriches’ the blood and circulation; and white atractylodes rhizome, Glycyrrhizae radix (liquorice root) and Ginseng radix are popular with Korean mothers.²²

Indications

Several complementary and alternative medicine approaches for nausea/vomiting, pain management, preconception, pregnancy or induction of labour have been used.²³ Several studies have described the use of herbal medicines for relief of stress and pregnancy-related symptoms, postpartum care, preparation for labour and for general health.²⁰ Other studies examined the efficacy of herbal medicines for nausea²⁴ and low back pain during pregnancy.²⁵

Preconception

The prevalence of the consumption of herbal drugs to enhance fertility is reported to be 8.3%–29% of patients attending infertility clinics in Australia.²⁶ Stankiewicz et al. found that green tea (27%, as an antioxidant), chamomile (13%), echinacea (8%), peppermint (7%), chaste tree berry, astragalus (5%), ginseng (4.2%) and horseradish (4%) were the herbal remedies used because it was believed that they enhanced fertility.²⁷

Herbal drugs used during pregnancy

Herbal supplements are taken to reduce or treat minor symptoms such as nausea and vomiting, indigestion/dyspepsia, backache, bladder/urinary symptoms, anxiety and to ‘boost’ the immune system.⁷ The choice and incidence of herbal medicine use varies during the different phases of pregnancy. Maats and Crowther²⁸ found that commonly used herbal medicines were ginger (42%) and chamomile (9%) in the first trimester, chamomile (13.6%) and ginger (9%) in the second trimester, and raspberry leaf tea (8%) and chamomile (6%) in the third trimester. Ginger is the most popular herb used to reduce or treat nausea and/or vomiting. Other antiemetics included wild yam (Dioscorea villosa) and red raspberry (Rubus idaeus) (Table 2).

Table 2.

Common herbs used during pregnancy.

Herb	Indication	Level of evidence
Ginger (Zingiber spp.)	Prevents nauseaTreatment of ‘morning sickness’Indigestion	1
Peppermint	NauseaMorning sicknessIndigestion	3
Cranberry	Prevention of urinary tract infectionsTreatment of urinary tract and vaginal infections	3
Chamomile	AnxiolyticMild hypnotic	3
Valerian (Valeriana officinalis)	AnxiolyticMild hypnotic	3
Raspberry	‘Strengthens’ uterusPrepares uterus for labour	3
Echinacea	Enhances immunityPrevents upper respiratory tract infections	3
Motherwort	Analgesia	4

Cervical ripening

Evening primrose oil is used by some midwives to trigger cervical ripening and therefore help initiate labour. In a retrospective study, evening primrose oil increased the incidence of prolonged rupture of membranes, oxytocin augmentation and vacuum extraction of the infant, shortening neither gestation nor duration of labour.²⁹ Other herbs used for cervical ripening include Lobelia inflata and Gossypium herbaceum (cotton root) (Table 3).

Table 3.

Herbs used prior to labour.

Herb	Actions and uses	Adverse events and contraindications	Level of evidence
Black cohosh (Cimicifuga racemosa)	Oestrogen effect*Decreases labour duration, promotes uterine contractionsMaintains uterine contraction after delivery	Headache, gastric discomfort if large doses used	4
Blue cohosh (Caulophyllum thalictroides)	Antispasmodic and uterine stimulantInduction of labour and augmentation of labour*Prevent miscarriages	*Coronary vasoconstriction and cardiac ischaemia Case report of myocardial infarction in infant born to a woman taking blue cohosh	4
Black haw (Viburnum prunifolium), cramp bark (Viburnum opulus)	Relieve false labour pains and afterpains by antispasmodic effects*Antispasmodic properties	Postural hypotension	4
Cotton root (Gossypium herbaceum)	Enhances endogenous oxytocinAids cervical ripeningInitiates or augments labour	Side-effects are those of oxytocin	4
Lobelia (Lobelia inflata)	Facilitates cervical dilation	Contraindicated in presence of hypertension	4

*observational event – low quality evidence.

Herbs used for induction of labour

Raspberry (usually taken as a tea), blue cohosh and castor oil are used in traditional midwifery either to ‘prepare’ the uterus for labour or stimulate the uterus. The mechanism of action of these herbal medicines in uterine stimulation is uncertain, although it has been proposed that they may have either a spasmolytic or stimulatory effect on the uterus. Although castor oil is commonly used as a laxative, midwives and parturients use it to initiate labour. Castor oil stimulates uterine contraction by increasing the production of prostaglandin F2 alpha in the uterus.³⁰ The mechanism of action of blue cohosh is mediated by glycosides (caulosaponin, caulophyllosaponin) and sparteine, which induce uterine contraction. However, they are not recommended as they have been associated with coronary vasospasm resulting in myocardial ischaemia in the fetus.³¹

Herbs used to relieve anxiety and pain during labour

A combination of herbs that have anxiolytic properties is commonly recommended (Table 2). A variety of herbs are used as anxiolytics to facilitate a pleasant experience in labour.³² Valerian, passionflower and chamomile are used for their calming and relaxation properties.³³

In the USA, independent midwives promoted the use of herbal remedies for the relief of labour pain and discomfort. In addition to massage therapy, hydrotherapy, breathing and relaxation techniques, they promoted herbal mixtures consisting of motherwort, wild ginger, lobelia, wild yam, blessed thistle, blue cohosh, squawvine, false unicorn and bayberry root to provide analgesia and relaxation. Most of the herbs either had anxiolytic effects or reduced dysfunctional labour by mild uterine stimulating effects. Labour pain was frequently treated with motherwort.¹

Herbs used in the postpartum period

Herbal medicines used to treat some of the symptoms during pregnancy may be continued into the postpartum period. Lavender oil is used to relieve perineal discomfort after vaginal delivery. A double-blind randomized clinical study failed to show any reduction in postnatal perineal discomfort.³⁴

There are different dietary practices in the postpartum period among different cultures. In Chinese culture, ‘ginger–vinegar soup’ is ingested to “enrich blood and strengthen internal organs”. The soup contains ginger, sweet vinegar, dates, chicken and pig trotters.³⁵ Large quantities of ginger may be consumed in the first month after delivery if this soup is consumed, which predisposes to the potential adverse effects of ginger.

St John’s wort is advocated for postnatal depression.^36,37 In a prospective, observational cohort study in 33 breastfeeding women receiving St John’s wort for postnatal depression no significant adverse effects associated with lactation or breastfeeding were found.³⁸

Most studied herbal medicines

Ginger

Ginger is a popular herbal drug in many Asian countries. It has been used in Chinese and Ayurvedic (Indian) traditional medicine for thousands of years to stimulate digestion and for its antiemetic, antitussive and anti-inflammatory properties. During pregnancy it is mainly used as an antiemetic in the first trimester. The use of ginger during pregnancy has been extensively studied in 10 randomized controlled trials (RCTs) (Level 1; grade B recommendation) (Table 4).

Table 4.

Randomized controlled trials using ginger for nausea and vomiting.

Study design	n	Ginger dose	Outcome	Reference
Double-blind RCTGinger vs placebo	120T = 60P = 60	5 g/day	Nausea & retching: better than placebo Vomiting: equal to placebo	³⁹
Double-blind RCTGinger vs placebo	70T = 32P = 38	1 g/day	Nausea & vomiting: better than placebo	⁴⁰
Single-blind RCTGinger vs placebo	67T = 32P = 35	1 g/day	Nausea & vomiting: better than placebo	⁴¹
Double-blind RCTGinger vs placebo	26T = 14P = 12	1 g/day	Nausea & vomiting better than placebo	⁴²
Double-blind cross over RCT	30T = 15Lactose = 15	250 mg/day	Nausea & vomiting better than placebo	⁴³
Double-blind RCTGinger vs vit B6	70Ginger = 36B6 = 34	1g/day or vit B6 40 mg/day	Equal to vit B6	⁴⁴
Double-blind RCTGinger vs vit B6	291	1.05 g/dayVit B6 75 mg/day	Equal to vit B6	⁴⁵
Double-blind RCTGinger vs dimenhydrinate	170T = 85D = 85	1 g/day or dimenhydrinate 100 mg/day	Equal to dimenhydrinate	⁴⁶
Double-blind RCTGinger vs vit B6	128T = 64B6 = 54	1.5 g/day or vit B6 30 mg/day	Equal to vit B6	⁴⁷
Double-blind RCTGinger vs vit B6	126T = 63B6 = 63	650 mg/day or vit B6 25 mg/day	Equal to vit B6	⁴⁸

RCT: randomized controlled trial; T: trial drug; P: placebo; D: dimenhydrinate.

Out of the 10 RCTs that evaluated the antiemetic effects of ginger, five RCTs^39–43 reported that ginger was superior in reducing nausea and vomiting compared with a placebo, whereas five^44-48 found ginger equally effective when compared with dimenhydrinate or vitamin B6. There were no increased adverse events or risks to the fetus.^49,50 The recommended daily dose of ginger for the treatment of nausea and vomiting is 1000 mg. It is proposed that the antiemetic properties of ginger are mediated by serotonin antagonism in the gut and the central nervous system (CNS). When the maximum daily dose of 4 g is exceeded, several adverse effects such as cardiac arrhythmias, CNS depression and coagulopathy may occur.⁵¹ Coagulopathy is caused by antiplatelet effects due to inhibition of thromboxane synthetase.⁵² Consequently, large doses of ginger should not be administered with antiplatelet drugs or warfarin.⁵³ Ginger should be used with caution in gestational diabetes because it has been reported to potentiate hypoglycaemia with insulin and the oral hypoglycaemic drugs.⁵¹

Cranberry

The main indication for taking cranberry during pregnancy is to prevent or treat urinary tract infection. The mechanism by which cranberry prevents urinary tract infection is mediated by two compounds in the fruit, fructose and proanthocyanidin, that prevent Escherichia coli from adhering to the urethral epithelial lining. In an RCT, Wing et al. investigated the efficacy of cranberry extract with placebo in prevention of urinary tract infection in pregnant women and reported multiple daily dosing reduced frequency of asymptomatic bacteriuria (57%) and urinary tract infection (41%).⁵⁴ However, the study was underpowered because 38.8% of subjects withdrew, most for gastrointestinal symptoms. The authors concluded that cranberry may have a protective effect against urinary tract infection during pregnancy but further larger studies are required (Level 3; grade C recommendation).

Raspberry

Since the 6th century, raspberry has been taken during pregnancy to shorten labour by augmenting uterine contractions and to reduce uterine bleeding. In an RCT, Simpson et al. reported that raspberry ingestion did not shorten the first stage of labour but reduced the rate of forceps delivery (19.3% versus 30.4%) and the duration of the second stage of labour (mean difference −9.5 min) (Level 3; grade C recommendation).⁵⁵ It is not associated with any maternal or fetal adverse effects.

Garlic

The traditional indication for garlic is to prevent colds, influenza and gastroenteritis⁵⁶ (Level 3; grade C recommendation). It has been suggested that it inhibits platelet aggregation and oxidative stress. This led to the hypothesis that garlic may be beneficial in pre-eclampsia. However, one RCT showed that it was not efficacious in reducing the incidence of hypertension or pre-eclampsia.⁵⁷ Consumption of large doses of garlic is associated with platelet dysfunction.⁵⁸

Blue cohosh

Blue cohosh is used as a uterine stimulant to induce and augment labour⁵⁹ in the late stages of pregnancy (Level 4; grade C recommendation). However, animal studies have reported serious coronary vasoconstriction resulting in myocardial ischaemia. Myocardial infarction in an infant born to a mother who had been taking blue cohosh during the last month of pregnancy has been reported.⁵⁴

Black cohosh

Black cohosh, which has oestrogen-like properties, is used in the last few weeks of pregnancy to promote rhythmic uterine contractions and maintain a contracted uterus after delivery⁵⁹ (Level 4; grade C recommendation). Unlike blue cohosh, no adverse effects have been reported.

Castor oil

Castor oil is used to initiate labour. A prospective study by Garry et al. showed a significant increase in the rate of initiation/induction of labour⁶⁰ (Level 4; grade D recommendation). However, Boel et al. showed that it increased nausea and could not demonstrate any effect on initiation of labour.⁶¹

Echinacea

Echinacea is used to promote the immune system to protect against upper respiratory tract infections. In a prospective cohort study of 206 pregnant women who used echinacea during the first trimester for upper respiratory tract ailments, respiratory symptoms in the treated group improved compared with the non-treated group (Level 3; grade C recommendation).⁶² There were no fetal malformations. Prolonged consumption of echinacea (>8 weeks) can cause liver dysfunction.⁶³

Chinese herbal medicines

Chinese herbal medicines usually contain either raw or processed ingredients from one or more plants. Animal or inorganic substances are sometimes added to the herbs. In some instances, conventional drugs such as steroids and NSAIDs are added but not disclosed.³ The common Chinese herbal products include An-Tai-Yin, Pearl power, Huanglian, Szu-Wu-Tang and Ginseng during pregnancy, and Sheng-Hua-Tang and Szu-Wu-Tang in the postpartum period.⁶⁴ Dong quai (Angelica sinensis) is taken as a powder contained in capsules by Chinese women for postpartum weakness and uterine hypotonia (Table 5). There are no good-quality studies on the safety and efficacy of the use of TCHMs (Level 5; grade D recommendation). Green tea (Melissa officinalis) can induce early maternal hypothyroidism, as the isoflavanoids inhibit thyroperoxidase and deiodinases resulting in low T3 levels.⁶⁵ Hypotension and delayed recovery from general anaesthesia may result from this unexpected hypothyroidism (Level 4 evidence).

Table 5.

Examples of Chinese herbal medicines used in pregnancy.

Herbal medicine	Ingredients	Level of evidence
‘An-Tai-Yin’	Fritillaria, Zingiber, Angelica, Radix liguistici, Paeonia, Astragali, Notopterygium, Magnoliae, Schizonepeta, Artenisiae, Citri immaturus, Argyi folium, Semen cuscutae	5
‘Huanglian’	Coptidis rhizome	5
Ginseng	Ginseng radix	5
‘Szu-Wu-Tang’	Rehmanniae radix, Paeoniae radix, Angelica sinensis, Chuanxiong rhizoma	5
‘Sheng-Hua-Tang’	Angelica radix, Ligustici rhizome, Semen persica, Zingiberis rhizome, Glycyrrhizea radix	5

Anaesthetic considerations

There are currently no clear data on the specific adverse interactions between herbal medicines and anaesthetic drugs. The available data on the risks and probable herb–anaesthetic drug interactions is based on case reports and limited pharmacodynamic/kinetic studies.

Self-prescription of herbal medicines is common. A high proportion of pregnant women (76%) fail to disclose to their midwife or obstetrician that they are taking herbal medicines.¹¹ A common reason for this lack of disclosure is simply because the women are not asked by their care providers.⁶⁶

As regional anaesthesia is advocated in obstetrics, the potential for coagulopathy and haemodynamic instability are major concerns. Large doses of garlic, ginseng and ginger impair platelet function by inhibiting thromboxane synthetase. Coagulopathy is only a concern when large doses of garlic, ginseng and ginger are consumed in the peripartum period (Level 4). Caution should be undertaken when managing postpartum Chinese women, as they may take large doses of ginger (>4 g) in the ‘ginger–vinegar soup’. In a study investigating the incidence and risk of perioperative events among surgical patients taking TCHMs, Lee et al. found that ginger consumption was not associated with prolonged aPTT or INR.⁶ They found no spinal or epidural haematomas in 133 patients who were taking TCHMs and who underwent regional anaesthesia. This supports the recommendations of the American Society of Regional Anesthesia Consensus on Neuraxial Anesthesia and Antithrombotic Therapy, which states that “herbal drugs, by themselves, appear to represent no significant risk for the development of spinal hematoma in patients having epidural or spinal anesthesia”.⁶⁷

When pregnant women take traditional Chinese or Ayurvedic medicines, the potential for adverse effects of contamination or undeclared added metals, steroids or NSAIDs should be considered. Lead and arsenic added to these traditional medicines can cause bone marrow depression, and the addition of NSAIDs can cause excessive bleeding.

Limitations of review

There are several limitations of this narrative review. As it was restricted to English language publications, issues related to publication bias arise especially as different cultures use different herbal medicines. Moreover, some medicinal plants are used as food and not as medicines. Much of the evidence comes from case reports and low-quality studies. The active constituents of the herbal medicines may vary in concentration and composition as they are not regulated.

Conclusion

Despite the popularity and widespread use of herbal medicines during pregnancy, there are very few good-quality studies of these drugs and their adverse effects. No definitive recommendations concerning the perioperative safety of these herbal medicines can be made because randomized double-blind placebo-controlled studies are not available. The American Society of Anesthesiologists⁶⁸ and the European Society of Anaesthesiology⁶⁹ guidelines on preoperative evaluation of adults undergoing elective non-cardiac surgery suggest that herbal medicines are stopped two weeks prior to surgery and that patients should be explicitly asked about their intake of herbal drugs (e.g. ginger, ginseng, garlic and gingko) that may impair coagulation. There is no evidence to postpone elective surgery, but for obstetric surgical procedures associated with massive haemorrhage it may be prudent to perform preoperative coagulation screening tests and use intraoperative point-of-care coagulation monitoring. Further research and longitudinal observational studies are required to provide clear data on the safety of herbal medicines in regard to anaesthesia.

Footnotes

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

References

Allaire

AD.

Complementary and alternative medicine in the labor and delivery suite.

Clin Obstet Gynecol 2001; 44: 681–691.

Hodges

Kam

PC.

The peri-operative implications of herbal medicines.

Anaesthesia 2002; 57: 889–899.

Kam

Liew

Traditional Chinese herbal medicine and anaesthesia.

Anaesthesia 2002; 57: 1083–1089.

Saper

Kales

Paquin

et al . Heavy metal content of ayurvedic herbal medicine products. JAMA 2004; 292: 2868–2873.

Levy

Attias

Ben-Ayre

et al . Adverse events associated with interactions with dietary and herbal supplements among inpatients. Br J Clin Pharmacol 2017; 83: 836–846.

Lee

Chui

Aun

CST

et al . Incidence and risk of adverse perioperative events among surgical patients taking traditional Chinese herbal medicines. Anesthesiology 2006; 105: 454–461.

Hall

Griffiths

McKenna

LG.

The use of complementary and alternative medicine by pregnant women: a systematic review.

Midwifery 2011; 27: 817–824.

Howick

Chalmers

Glasziou

et al . Explanation of the 2011 Oxford Centre for Evidence-based Medicine levels of evidence (background document) http://www.cebm.net/index.aspx?o+5623 (accessed 6 November 2018).

Kennedy

Lupatelli

Koren

et al . Herbal medicine use in pregnancy: results of a multinational study. BMC Complement Altern Med 2013; 13: 355. http:/www.biomedcentral.com./1472-6882/13/355 (accessed 20 July 2018).

10.

Frawley

Adams

Sibbritt

et al . Prevalence and determinants of complementary and alternative medicine use from a nationally representative sample of Australian pregnant women. Aust N Z J Obstet Gynaecol 2013; 53: 347–352.

11.

Holst

Wright

Haavik

et al . Safety and efficacy of herbal remedies in obstetrics: review and clinical implications. Midwifery 2011; 27: 80–86.

12.

Nordeng

Bayne

Havnen

et al . Use of herbal drugs. Complement Ther Clin Pract 2011; 17: 147–151.

13.

Lapi

Vannacci

Moschini

et al . Use, attitudes and knowledge of complementary and alternative drugs (CAS) among pregnant women: a preliminary survey in Tuscany. Evid Based Complement Alternat Med 2010; 7: 477–486.

14.

Mousally

Oriachi

Bérard

Herbal products use during pregnancy: prevalence and predictors.

Pharmacoepidemiol Drug Saf 2009; 18: 454–461.

15.

Louik

Gardiner

Kelley

et al . Use of herbal treatments in pregnancy. Am J Obstet Gynecol 2010; 202: e431–e410.

16.

Yusof

Mahdy

Noor

RM.

Use of complementary and alternative medicine in pregnancy and its impact on outcome.

Complement Ther Clin Pract 2016; 25: 155–163.

17.

Tang

Lee

Binns

et al . Consumption of Chinese herbal medicines during pregnancy and postpartum: a prospective cohort study in China. Midwifery 2016; 34: 205–210.

18.

Dante

Pedrielli

Annessi

et al . Herb remedies during pregnancy: a systematic review of controlled clinical trials. J Matern Fetal Neonatal Med 2013; 26: 306–312.

19.

Hepner

Harnett

Segal

et al . Herbal use in parturients. Anesth Analg 2003; 94: 690–693.

20.

Adams

Lui

Sibbritt

et al . Women’s use of complementary and alternative medicine during pregnancy: A critical review of the literature. Birth 2009; 36: 237–245.

21.

McLay

Izzah

Pailvalapila

et al

. Pregnancy, prescription medicines and the potential risk of herb-drug interactions: A cross sectional survey.

BMC Complement Altern Med 2017; 17: 543.

22.

Lee

et al . Use and safety of Korean herbal medicine during pregnancy: a Korean medicine literature review. Eur J Integr Med 2016; 8: 4–11.

23.

Mathews

Haas

O’Mathuna

et al . Interventions for nausea and vomiting in early pregnancy. Cochrane Database of Systematic Reviews 2014; 3: CD007575.

24.

Hollyer

Boon

Geogousis

et al . The use of CAM by women suffering from nausea and vomiting during pregnancy. BMC Complement Alternat Med 2002; 2: 5. http://www.biomedcentral.com/1472-6882/2/5.

25.

Wang

DeZinno

Fermo

et al . Complementary and alternative medicine for low-back pain in pregnancy: A cross-sectional survey. J Altern Complement Med 2005; 30: 138–143.

26.

Charaf

Wardle

Sibbritt

et al . Women’s use of herbal and alternative medicines for preconception care. Aust N Z J Obstet Gynaecol 2015; 55: 222–226.

27.

Stankiewicz

Smith

Alvino

et al . The use of complementary medicines and therapy by patients attending a reproductive medicine unit in South Australia: A prospective survey. Aust N Z J Obstet Gynaecol 2007; 47: 145–149.

28.

Maats

Crowther

CA.

Patterns of vitamin, mineral and herbal supplement use prior to and during pregnancy.

Aust N Z J Obstet Gynaecol 2002; 42: 494–496.

29.

Dove

Johnson

Oral evening primrose oil: its effect on the length of pregnancy and selected intrapartum outcomes in low risk nulliparous women.

J Nurse Midwifery 1999; 44: 320–324.

30.

Garry

Figueroa

Guillaume

et al . Use of castor oil in pregnancies at term. Altern Ther Health Med 2000; 6: 77–79.

31.

Jones

Lawson

BM.

Profound neonatal congestive heart failure caused by maternal consumption of blue cohosh herbal medication.

J Pediatr 1998; 132: 550–552.

32.

Gentz

BA.

Alternative therapies for the management of pain in labour and delivery.

Clin Obstet Gynaecol 2001; 44: 704–732.

33.

Bruno

Simoes

et al . Pregnancy and herbal medicines: an unnecessary risk for women’s health: a narrative review. Phytother Res 2018; 32: 796–810.

34.

Dale

Cornwell

The role of lavender oil in relieving perineal discomfort following childbirth.

J Adv Nurs 1994; 19: 89–96.

35.

Chan

Nelson

EAS

Leung

SSF

et al.

Special postpartum dietary practices of Hong Kong Chinese women. Eur J Clin Nutr 2000; 54: 797–802.

36.

Moretti

Maxson

Hanna

et al . Evaluating the safety of St John’s wort in human pregnancy. Reproductive Toxicol 2009; 28: 96–99.

37.

Grush

Nierenberg

Keefe

et al . St John’s wort during pregnancy. JAMA 1998; 280: 1566.

38.

Lee

Minhas

Lam

et al . The safety of St John’s wort (Hypericum perforatum) during breast feeding. J Clin Psychiatry 2003; 64: 966–968.

39.

Willetts

Ekangaki

Eden

JA.

Effect of a ginger extract on pregnancy induced nausea: a randomized controlled trial.

Aust NZ J Obstet Gynaecol 2003; 43: 139–144.

40.

Vutyavanich

Kraisarin

Ruangsri

Ginger for nausea and vomiting in pregnancy: randomized, double-masked, placebo controlled trial.

Obstet Gynecol 2001; 97: 577–582.

41.

Ozogoli

Goli

Simbar

Effects of ginger capsules on pregnancy, nausea and vomiting.

J Altern Complement Med 2009; 15: 243–246.

42.

Keating

Chez

RA.

Ginger syrup as an antiemetic in early pregnancy. Alternative Therapies Health and Medicine 2002; 8: 89–91.

43.

Fischer-Rasmussen

Kjaer

Dahl

et al . Ginger treatment of hyperemesis gravidarum. Eur J Obstet Gynaecol Reprod Biol 1991; 38: 19–24.

44.

Ensiyeh

Sakineh

MA.

Comparing ginger and vitamin B6 for the treatment of nausea and vomiting in pregnancy.

Midwifery 2009; 25: 649–653.

45.

Smith

Crowther

Willson

et al . A randomized controlled trial of ginger to treat nausea and vomiting in pregnancy. Obstet Gynecol 2004; 103: 639–645.

46.

Pongrojpow, Somprasit

Chanthasenanont

A randomized comparison of ginger and dimenhydrate in the treatment of nausea and vomiting in pregnancy.

J Med Thai Assoc 2007; 90: 1703–1709.

47.

Sripramote

Lekhyananda

A randomized comparison of ginger and Vitamin B6 in the treatment of nausea and vomiting in pregnancy.

J Med Assoc Thai 2003; 86: 846–853.

48.

Chittumma

Kaewkiattkun

Wiriyasiriwach

Comparison of the effectiveness of ginger and Vitamin B6 for treatment of nausea and vomiting in early pregnancy: A randomised double blind controlled trial. J Med Assoc Thai 2007; 90: 15–20.

49.

Portnoi

Chng

Karimi-Tabesh

et al . Prospective comparative study of the safety and effectiveness of ginger for the treatment of nausea and vomiting in pregnancy. Am J Obstet Gynecol 2003; 189: 1374–1377.

50.

Heitman

Nordeng

Holst

Safety of ginger use in pregnancy: results from a large population cohort study.

Eur J Clin Pharmacol 2013; 69: 269–277.

51.

Ding

Leach

Bradley

The effectiveness and safety of ginger for pregnancy-induced nausea and vomiting: A systematic review. Women Birth 2013; 26: e26–e30.

52.

Backon

Ginger as an antiemetic: possible side effects due to its thromboxane synthetase activity.

Anaesthesia 1991; 46: 705–706.

53.

Smith

Crowther

Wilson

et al . A randomized controlled trial of ginger to treat nausea and vomiting in pregnancy. Obstet Gynecol 2004; 103: 639–645.

54.

Wing

Rumney

Preslicka

et al . Daily cranberry juice for the prevention of asymptomatic bacteriuria in pregnancy: A randomized controlled pilot study. J Urol 2008; 180: 1367–1372.

55.

Simpson

Parsons

Greenwood

et al . Raspberry leaf in pregnancy: its safety and efficacy in labour. J Midwifery Womens Health 2001; 46: 51–59.

56.

Lissiman

Bhasale

Cohen

Garlic for the common cold. Cochrane Database Syst Rev 2012; 3: C006206.

57.

Ziaer

Hantoshzadeh

Rezasoltani

et al . The effect of garlic tablet on plasma lipids and platelet aggregation in nulliparous pregnancy at high risk of preeclampsia. Eur J Obstet Gynecol Reprod Biol 2001; 99: 201–206.

58.

Rose

Crossaint

Parliament

CF.

Spontaneous spinal epidural hematoma with associated platelet dysfunction from excessive garlic ingestion: a case report.

Neurosurgery 1990; 26: 880–882.

59.

Wright

Neonatal effects of maternal consumption of blue cohosh.

J Pediatr 1999; 134: 384–385.

60.

Garry

Figuera

Guillaume

et al . Use of castor oil in pregnancies at term. Altern Ther Health Med 2000; 6: 77–79.

61.

Boel

Lee

Rijken

et al . Castor oil for induction of labour: not harmful, not helpful. Aust NZ J Obstet Gynaecol 2009: 49; 499–503.

62.

Gallo

Sarkar

et al . Pregnancy outcome following gestational exposure to Echinacea. Arch Intern Med 2000; 160: 3141–3143.

63.

Miller

LG.

Selected clinical considerations focusing on known or potential drug-herb interactions.

Arch Intern Med 1998; 158: 2200–2211.

64.

Chuang

Chang

Hsieh

et al . Chinese Herbal medicine use in Taiwan during pregnancy and the postpartum period: a population-based cohort study. Int J Nurs Stud 2009; 46: 787–795.

65.

Roman

GC.

Autism: Transient in utero hypothyroxinemia related to maternal flavoid ingestion during pregnancy and other environmental antithyroid agents. J Neurol Sci 2007; 262: 15–26.

66.

Harrigan

JT.

Patient disclosure of their use of complementary and alternative medicine to their obstetrician/gynaecologist.

J Obstet Gynaecol 2011; 31: 59–61.

67.

Horlocker

Wedel

Benson

et al . Regional anesthesia in the anticoagulated patient: defining the risks (the second ASA Consensus Conference on Neuraxial Anesthesia and Anticoagulation). Reg Anesth Pain Med 2003; 28: 172–197.

68.

Leak

JA.

Perioperative considerations in the management of patients taking herbal medicines. Curr Opin Anaesthesiol 2000; 13: 667–669.

69.

De Hart

Staender

Fritsch

et al . Preoperative evaluation of adults undergoing elective non-cardiac surgery: updated guideline from the European Society of Anaesthesiologists. Eur J Anaesthesiol 2018; 35: 407–465.

Herbal medicines and pregnancy: A narrative review and anaesthetic considerations

Abstract

Keywords

Search strategy

Prevalence

Indications

Preconception

Herbal drugs used during pregnancy

Cervical ripening

Herbs used for induction of labour

Herbs used to relieve anxiety and pain during labour

Herbs used in the postpartum period

Most studied herbal medicines

Ginger

Cranberry

Raspberry

Garlic

Blue cohosh

Black cohosh

Castor oil

Echinacea

Chinese herbal medicines

Anaesthetic considerations

Limitations of review

Conclusion

Footnotes

Declaration of conflicting interests

Funding

References