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Medicines Q&As
Is it safe to take herbal medicines during pregnancy?
Prepared by UK Medicines Information (UKMi) pharmacists for NHS healthcare professionals
Before using this Q&A, read the disclaimer at https://www.sps.nhs.uk/articles/about-ukmi-medicines-qas/
Date prepared: 23 February 2017
Background
An observational cohort study in South West England found that 26.7% (n=3774) of women had used
a complementary or alternative medicine at least once during pregnancy; the use rising from 6%
(n=824) in the first trimester to 12.4% (n=1639) in the second and to 26.3% (n=3269) in the third (1).
Only 7.6% (n=1073) of women did not take any medicinal products (conventional or complementary)
throughout the whole of their pregnancy. The most common herbal products were chamomile,
peppermint, raspberry leaf and rosehip. Use of complementary medicines increased with age of the
mother, with older mothers more likely to have used a complementary medicine than younger
mothers (43.5% aged over 35 years and 15.2% aged 24 years or under) (1). Another United Kingdom
(UK)-based study reported 57.8% (n=334) of women used herbal remedies during pregnancy, with a
mean of 1.2 remedies (range 0-10) per woman. The most commonly used remedies were ginger,
cranberry and raspberry leaf (2). Of some concern is that 76% of the pregnant women reported not
informing their doctor or midwife that they were using herbal medicines, and that family or friends
were the most frequently cited source of information about herbal remedies during pregnancy (2).
One survey involving 600 postpartum women in Norway found that 39.7% had used herbal medicines
during pregnancy with an average of 1.6 products per woman. Echinacea, iron-rich herbs, ginger,
chamomile and cranberry were the most commonly used herbal medicines (3).
Evening primrose oil, ginseng, green tea, flax and valerian are also reportedly commonly used by
women during pregnancy (4-6).
Herbal medicines are often mistakenly viewed as natural and safe alternatives to conventional
medicines. Unfortunately, some plants have toxic constituents and many have constituents with
pharmacological activity, such as stimulation of uterine muscle, which could render them unsuitable
during pregnancy (7). Contamination with substances such as pesticides, conventional medicines or
heavy metals cannot be ruled out. There is a published case report of a preterm infant found to have
elevated blood lead levels as a result of the long-term ingestion of lead-contaminated herbal
medicines by the mother (8). Lead poisoning has been reported in association with the use of
Ayurvedic medicines by pregnant women (9). These products may contain herbs only, or in some
cases are combined with metals, minerals or other materials (10).
Preparations often differ with regard to the concentration and origin of their constituent herbs (11).
Furthermore, many modern herbal preparations are available as highly concentrated extracts, the
effects of which could differ substantially from those of more traditional preparations such as teas
made from the leaves of herbs. Therefore the assumption should not be made that a preparation will
be safe merely because its main herbal ingredient has been used during pregnancy for many years
without apparent ill effect (11). As with conventional drugs, the route of administration (e.g. oral or
topical) and the preparation (e.g. capsule or tincture) should be considered when determining the
safety of an herbal medicine. Finally, any assessment of risk should take into account potential
interactions between the herbal preparation(s) and any conventional medicine(s) a women is taking,
as well as her past obstetric history and general health.
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Answer
Few scientific studies have looked at the effects of herbal medicines in pregnant women and literature
reporting the outcome of pregnancies during which herbal medicines were used is limited. Because of
the scarcity of relevant safety information, use of herbal medicines during pregnancy cannot be
recommended. Despite this, it is clear that many pregnant women use herbal preparations,
particularly for pregnancy-related symptoms. The following information covers the herbal medicines
most likely to be in common usage by pregnant women.
Almond oil (Sweet almond)
A retrospective multicentre study performed in postpartum women found a significant association
between daily topical application of almond oil to the abdomen (to alleviate stretch marks) and
preterm (<37th week) birth (12). Further data is needed to clarify the causality of this relationship.
Authors state that results should be interpreted with caution due to the retrospective nature of the
study. Almond oil should be avoided due to insufficient reliable information about its safety in
pregnancy (13).
Blue Cohosh
Blue cohosh has traditionally been used to induce labour (14). It is not recommended during
pregnancy because the potential foetal and newborn toxicity appears to outweigh any maternal
benefit (14). There are three case reports in the literature of potential adverse effects in the neonate
following maternal exposure to blue cohosh around the time of delivery. In the first case, stroke was
reported in a neonate whose mother had taken a tea made of blue cohosh (15). The tea was found to
contain a metabolite of cocaine and the authors noted that maternal use of cocaine is a cause of
perinatal stroke. It is unclear if the cocaine metabolite was also a metabolite of blue cohosh or a
contaminant in the tea. No follow up details are provided for this case. In the second case report a
neonate experienced a myocardial infarction (MI) associated with congestive heart failure and shock
(16). The mother had taken three times the recommended daily amount of blue cohosh tablets for
three weeks to induce labour. The authors state that other causes of MI were ruled out. The infant
went on to recover though some cardiac symptoms persisted at 2 years of age (16). In the third case
severe multi-organ hypoxic injury was reported in a neonate whose mother had taken a blue and back
cohosh herbal mixture (17). At three months there was lower limb spasticity and the infant required
nasogastric tube feeding (17). In vitro evidence suggests that blue cohosh may have teratogenic,
embryotoxic and oxytoxic effects (18). There have been calls for tighter control of its use and for
further investigations into its safety (18).
Chamomile
Traditionally, chamomile is used as a mild sedative and to aid digestion (3), and has reportedly been
used for the treatment of morning sickness (14). There are two types of chamomile – German and
Roman. German chamomile is the type used most often as a medicinal herb, extracts of which have
been reported to increase the tone of uterine muscle (19). There is a documented case in which a 35year-old woman received an enema made from German chamomile and experienced life-threatening
anaphylaxis; her baby experienced severe asphyxia and died the following day (20, 21).
Two cases of premature constriction of the foetal ductus arteriosus have been reported following the
maternal consumption of chamomile herbal tea (22). The first patient reported drinking chamomile tea
on a regular basis. A constricted ductus arteriosus and increased blood velocity across it was seen at
20 weeks’ gestation on foetal echocardiography, including Doppler velocity. The patient was advised
to stop drinking the tea and re-assessed one week later, which revealed complete resolution of ductal
constriction with no acceleration in blood flow velocity across the ductus arteriosus (22). The second
case was referred for foetal cardiac assessment at 35 weeks’ gestation on suspicion of foetal
tachycardia. Doppler imaging confirmed high diastolic flow velocities with a pattern consistent with
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ductal constriction. The patient confirmed intermittent consumption of chamomile tea during
pregnancy, including about 48 hours before the scan (22). The authors have postulated that ductal
constriction associated with the consumption of chamomile tea is likely to be produced by a similar
pharmacological mechanism to that observed with non-steroidal anti-inflammatory drugs, due to its
inhibitory effects on the cyclo-oxygenase and lipo-oxygenase pathways of arachidonic acid
metabolism (22).
Roman chamomile is believed to be an abortifacient (19, 23) and is possibly unsafe when used orally
in medicinal amounts (23). The excessive use of roman chamomile during pregnancy should be
avoided (19).
Due to insufficient data on the use of German chamomile, it too should be avoided during pregnancy
until further information is available (14). However, the risk from consumption of the herb, especially
from occasional use, must be very rare because chamomile has been used for thousands of years and
is frequently used during pregnancy as a tea or infusion (14). Although there are no data to suggest how
much is “safe”, it is suggested that consumption of herbal teas be limited to two cups per day during
pregnancy (24).
Cranberry
Cranberry is used orally to prevent and treat urinary tract infections (25). Reliable scientific
information on the use of cranberry during pregnancy is not available (25, 26).
Pregnancy outcome after use in pregnancy was studied using data from the Norwegian mother and
child cohort study (27). Among 68,552 women in the study, 919 (1.3%) reported use of cranberry
during pregnancy. The daily dose, duration of treatment, frequency of treatment and dietary intake of
cranberry products (e.g. juice, berries) were not specified.
No increased risk of malformations or other adverse outcomes were found. An association was found
between use of cranberry in late pregnancy and vaginal bleeding after pregnancy week 17, however
further sub-analyses of more severe bleeding outcomes did not support a significant risk. Maternal
vaginal bleeding should be investigated further before any firm conclusions can be drawn.
Cranberry at the doses normally found in foods are not known to cause problems in pregnancy, but
until sufficient reliable information is available about its safety, therapeutic doses of cranberry should
be avoided by pregnant women (19, 25).
Echinacea
Echinacea is commonly used orally to treat and prevent the common cold and other upper respiratory
infections (28). Two prospective studies have looked at pregnancy outcomes after gestational
exposure to echinacea. The first study (29) included 412 pregnant women who had contacted a
teratogen information service to ask about the safety of echinacea for an upper respiratory tract
illness. The study group comprised those who went on to take echinacea (n=206), whereas those who
chose not to use it or used a non-teratogenic antibiotic instead formed the control group (n=206). In
the study group, use of echinacea was generally for between five and seven days and 54% (n=112) of
women used echinacea during the first trimester. The groups did not differ statistically significantly
with regard to pregnancy outcome, delivery method, gestational age, birth weight or foetal distress. In
the study group, 6 major and 6 minor malformations occurred and in the control group there were
seven major and seven minor malformations. As the authors noted, limitations of the study included
the small sample size and lack of standardisation of doses (tablets, capsules and tinctures in varying
doses were used) (29).
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The second study (30), a prospective survey based on the Norwegian Mother and Child Cohort Study,
compared outcomes between 363 echinacea-exposed pregnancies and 68,159 unexposed women.
There were no differences in preterm birth, low birth weight, smallness for gestational age, or
malformations between exposed and unexposed women.
In the absence of sufficient data and its unestablished benefits (19), echinacea should be avoided
during pregnancy as a general precaution unless advised by a doctor (31).
Evening Primrose Oil
Evening primrose oil has been used orally in pregnancy for preventing pre-eclampsia, shortening
duration of labour, stimulating labour and preventing post-date deliveries (32). One study compared
outcomes in 54 women who took evening primrose oil orally from week 37 of pregnancy with those in
54 women who did not. No difference in the overall length of labour was found between groups.
Further, it was concluded that women taking evening primrose oil might be more likely to experience
prolonged rupture of membranes, oxytocin augmentation, arrest of descent and vacuum extraction
(33).
One report was found of ecchymoses and petechiae on the trunk, extremities and face of a newborn
infant. The infant had no other symptoms. In the week before delivery her mother had taken raspberry
leaf tea and a total of thirteen 500mg capsules of evening primrose oil, vaginally and orally, in an
attempt to improve labour. The authors suggested that the evening primrose oil had inhibited platelet
function in the newborn infant. The platelet count was reported as normal in the infant and her
symptoms resolved spontaneously by day 5 (34).
In the absence of safety data, it is recommended that evening primrose oil be avoided during
pregnancy (19).
Flax
There is very little information on the effects of flax during human pregnancy, but it might have
oestrogenic effects, which would be a cause for concern in a pregnant woman (35). One study found
that flax use during the last two trimesters of pregnancy was associated with an increased risk of
preterm birth (36). In the absence of sufficient safety data during pregnancy and its potential
oestrogenic effects, use during pregnancy is not recommended (37).
Ginger (root)
Between 50 and 80% of women experience nausea during pregnancy (38). A Cochrane review on
interventions for nausea and vomiting during pregnancy concluded that the use of ginger may be
helpful to women, but the evidence of effectiveness was limited and inconsistent (38). The current
National Institute for Health and Clinical Excellence (NICE) guidance on antenatal care highlighted
that ginger appears to be an effective intervention in reducing nausea and vomiting symptoms in early
pregnancy (39).
According to information produced by the UK Teratology Information Service (UKTIS), two cohort
studies and several small clinical trials found no increase in the incidence of adverse pregnancy
outcomes, including congenital malformations, when ginger was used during pregnancy. Despite this,
since only small numbers of pregnant women have been exposed to ginger in studies, the risk of
adverse effects cannot be completely ruled out (40).
The authors of a recent systematic review identified 14 randomised controlled trials (RCTs) related to
herb efficacy in pregnancy. Ginger was the most investigated herb (10 RCTs) and was consistently
reported to ameliorate nausea and vomiting during pregnancy better than placebo (41). Five RCTs
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reported the superiority of ginger compared to placebo, whereas four other trials found ginger to be
equally effective when compared to vitamin B6 and dimenhydrinate. Ginger doses in the trials ranged
from 250mg/day to 5 grams/day for a duration of 4 days to 3 weeks. Minor adverse effects including
inability to tolerate treatment, sedation, heartburn and allergic reactions were reported. No significant
differences between ginger, vitamin B6 and dimenhydrinate with respect to adverse effects were
found (41).
A prospective observational cohort study involved 187 women exposed to ginger during the first
trimester of pregnancy and 187 women exposed to non-teratogenic drugs. Dosage and origin of the
ginger were not documented. No statistically significant differences were noted between the two
groups for live births, spontaneous abortions, still births, therapeutic abortions, birth weight or
gestational age (42).
Similar conclusions were reached in a study conducted in Norway in which over 68,000 women were
given questionnaires to complete during weeks 17 and 30 of their pregnancy and when their child was
6 months old. One thousand and twenty women reported using ginger during pregnancy. No
differences were found between women who had been exposed to ginger during pregnancy and
those who had not with regard to the risk of congenital malformations, stillbirth/perinatal death,
preterm birth, low birth weight, or low Apgar score. However, compared to controls, a higher
percentage of the women who took ginger after week 17 experienced vaginal bleeding (7.8% versus
5.8%, p=0.007). When the investigators looked specifically at vaginal bleeding that was more than
spotting, the association was no longer significant (43).
Concern has been raised that the thromboxane synthetase inhibitory action of ginger could affect
testosterone receptor binding (14) thereby possibly altering sex steroid differentiation of the foetal
brain (44). Ginger also has limited potential to stimulate uterine smooth muscle (45). Despite these
theoretical concerns, the risk posed by ginger to the foetus is considered to be low (14, particularly
when it is used at the doses found in foods (45). However, it has been suggested that doses of ginger
higher than 1g/day should be avoided during pregnancy (45).
Ginseng (Panax)
Little information is available on the safety of ginseng during pregnancy in humans (or animals) and
further data are warranted (14). In non-pregnant patients, hypertension and hypoglycaemia have
been reported with ginseng and these effects could complicate pregnancies with hypertensive
disorders or diabetes (14). It is possible that ginseng has oestrogen-like properties (46) and is
therefore not recommended during pregnancy (24).
A study in which 88 women who had taken ginseng during pregnancy were matched with 88 controls,
found no statistically significant differences between groups in birth weight, mode of delivery, preterm
delivery, low Apgar scores, stillbirths or neonatal death. No mention was made of congenital
malformations (47).
Pregnancy outcome was reported for 149 cases of exposure to ginseng during the first trimester of
pregnancy (48). In 116 of these cases, foetal exposure was to ginseng alone. Of the children born to
women who had taken ginseng alone during the first trimester, six had malformations, but evaluation
by individual defect category did not indicate that the risk of malformation was significantly higher than
that in a control group in which herbal medicines had not been used (48, 49). It is interesting to note
that in traditional Chinese medicine ginseng is contraindicated in pregnant and lactating women
except in the treatment of specific conditions (49).
There is one report of androgenisation in a neonate exposed to ginseng in the womb and through
breastfeeding (50), however the cause of the androgenisation was later reported to be most likely
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caused by the mother taking Periploca sepium (silk vine) rather than ginseng (51). Therefore causality
has not been established.
Green Tea
There is limited evidence regarding the use of green tea during pregnancy (52). Large quantities of
green tea should be avoided by pregnant women because of their caffeine content (52, 53). Caffeine
crosses the placenta producing foetal blood concentrations similar to maternal levels (52). NHS
Choices advises pregnant women not to consume more than 200mg caffeine per day because higher
caffeine intakes might cause miscarriage or low birth weight (54).
Iron-rich herbs
During pregnancy the need for iron increases and may not be sufficiently covered by food or maternal
iron stores (55). Several different preparations of iron-rich herbs are available. The quantity of iron
found in these products may vary greatly and the risk of contaminants cannot be ruled out. If a
patients thinks they may be iron deficient then this should be verified by their doctor who can
prescribe appropriate treatment.
Peppermint
Some sources suggest that peppermint in large doses during pregnancy might have an
emmenagogue (stimulating menstruation) and abortifacient effect (14, 56). Peppermint has been
traditionally used for hundreds of years; one source suggests that in the absence of medical literature
reporting adverse effects, that there is little risk from the typical use of this herb in pregnancy (14).
Given the lack of published information to support the use of therapeutic doses of peppermint oil
during pregnancy, the UKTIS does not recommend its use during this period unless there is a
compelling clinical need (57).
Raspberry leaf
Raspberry leaf is used by women during pregnancy for morning sickness and to shorten and facilitate
labour (58). One source suggests that raspberry leaf may have oestrogenic effects which could
adversely affect pregnancy (58). There is also limited and conflicting evidence that it affects uterine
contractions (19).
The safety of raspberry leaf during pregnancy was investigated in a prospective, randomised,
controlled study (59) and a retrospective record review study (60). The prospective study required 240
nulliparous women to take raspberry leaf tablets (2 x 1.2g/day) (n=96 completed study) or placebo
(n=96 completed study) from gestational week 32 until labour; whereas in the retrospective study, the
women who took raspberry leaf (n=57; n=51 in control group) started as early as week 8 of their
pregnancy. In the retrospective study, a variety of raspberry leaf preparations were taken, e.g. tea,
tablets and/or tincture. Neither study showed a significant difference in efficacy between groups in the
first or third stages of labour however shortening of the second stage of labour and a lower rate of
forceps deliveries was observed between treatment and control groups in the prospective study (59).
With regard to safety, both studies found neither maternal nor infant safety to be affected by raspberry
leaf consumption. Neither study found a difference between the two groups in the occurrence of
meconium-stained amniotic fluid (59, 60) presence of meconium in the amniotic fluid would indicate
that the baby was under stress (61). Maternal and infant safety measures differed between the
studies, but both took into account maternal blood loss at birth, maternal diastolic blood pressure
(timings different in each study), and the occurrence of side-effects in study participants, newborn
admission to a neonatal unit/special care baby unit and newborn Apgar score at 5 minutes. However,
these studies were not large and may not have detected rare effects.
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A recent Norwegian study highlighted a significant association between the use of raspberry leaves in
pregnancy and caesarean delivery (23.5% versus 9.1% amongst women with no use of herbal drugs
[adjusted OR 3.47, 95% CI 1.45-8.28]) (3). However, current NICE guidance on caesarean sections
supports the findings of the previously mentioned prospective study (59) and indicates that the use of
raspberry leaf during pregnancy has not been shown to influence the likelihood of caesarean delivery
(62).
Despite being used to ease labour pains (24), raspberry leaf does not appear to reduce the length of
labour or decrease the need for analgesics in the perinatal period (58). Due to lack of evidence for its
efficacy and safety, it is advised that medicinal amounts of raspberry leaf be avoided during
pregnancy and labour unless taken under the guidance of a healthcare professional (58).
Rose Hip
There is very little scientific information available on the use of rosehip during pregnancy. It is advised
that quantities of rosehip greater than those found in foods are not used during pregnancy (63).
St John’s Wort
Hypericum perforatum, also known as St John’s wort, is a common herbal treatment option for
depression. However, there is little evidence to support the safe use of St John’s wort in pregnancy.
St John’s wort induces CYP 3A4 and P-glycoprotein, and therefore has the potential to interact with
many drugs (24). In their clinical guidelines on the management of depression, NICE advise that St
John’s wort should be avoided (64). However, unintentional exposure to St John’s wort during early
pregnancy may occur. One study followed 54 St John’s wort exposed pregnancies (49 exposed
during the first trimester) and compared the outcomes to those of 54 pregnancies in which the foetus
was exposed to conventional antidepressants, and 54 pregnancies in which the mothers were not
known to suffer from depression or to take any teratogenic drugs (65). Rates of major malformation
were not significantly different between the groups (5% (St John’s wort group) versus 4% (diseasematched group) and 0% (healthy group) p=0.26). Similarly, there were no significant differences
between groups in terms of foetal outcome (p=0.28), preterm delivery (p=0.10) or birth weight
(p=0.51) (65). Though these results are encouraging further large scale studies are required.
A literature report revealed two cases of exposure to St John’s wort in pregnancy, only one of which
provides any outcome data in the infant. A 38 year old woman took 900mg/day of St John’s wort from
week 24 of her pregnancy until 24 hours prior to delivery. The woman breast fed and restarted the St
John’s wort at 300mg/day on day 20. Behavioural assessments of the neonate at 4 and 33 days were
within the normal range (66).
Using data from the Danish National Birth Cohort, Kolding et al. investigated outcomes amongst 38 St
John’s wort-exposed pregnancies compared to a group of 90,128 women (67). Pregnancy outcomes
were similar in the two groups though malformations were identified in 3/37 (8.1%) of the St John’s
wort-exposed pregnancies compared with 2891/86745 (3.3%) in the comparator group (p=0.13).
Malformations included hypospadias, bilateral hip dislocation and heart septum defect. Authors state
that “the identified malformations were not associated with a clear anatomical pattern and importantly,
the increased prevalence was based on only three exposed cases and could be a chance finding.”
In the absence of sufficient safety data, use during pregnancy is not recommended (68).
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Valerian
Valerian is used as a sedative and hypnotic for anxiety, restlessness and sleep disturbances (14).
There is little scientific evidence to support the use of valerian during human pregnancy (14, 24) and
therefore its use by pregnant women is not recommended (19, 69).
Other herbal medicines
A prospective cohort of pregnant women of 26 weeks or greater gestation were entered into a hospital
study in Taiwan to estimate the risk of major congenital malformations following herbal use in the first
trimester. A total of 14,551 live births were analysed. 16.9% of mothers had taken any herbal
preparation in the first trimester; An-Tai-Yin and huanglian were the most commonly used, 11.4% and
1.5%, respectively. Adjusting for confounding factors, taking huanglian during the first trimester was
associated with an increase risk of congenital malformation of the nervous system (OR 8.62, 95% CI:
2.54 to 29.24) and increased risk to external genital organs (OR 3.82, 95% CI: 1.18 to 12.40). An-TaiYin was associated with an increased risk of muscle and connective tissue (OR 1.61, 95% CI: 1.10 to
2.36) and eye congenital malformations (OR 7.30, 95% CI: 1.47 to 36.18). Pre-existing maternal
disease was not found to affect these results with the possible exception of huanglian and its effects
on external genital organs. Limitations of the study included only assessing live born infants and lack
of standardisation of the herbal products consumed by the mothers (48).
In their report on the safety of herbal medicines (2002), the Medicines Control Agency (now the
Medicines and Healthcare Products Regulatory Agency [MHRA]) lists herbal ingredients that should
be avoided or used with caution during pregnancy (70).
It draws attention specifically to the following herbs:
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Herbs containing volatile oils that are irritant to the genito-urinary tract: ground ivy,
juniper, parsley, pennyroyal, sage, tansy and yarrow (Also see practical advice below)
Herbs with documented stimulant/spasmolytic action on uterine muscle: blue cohosh
(see above), burdock, fenugreek, golden seal, hawthorn, Jamaica dogwood, motherwort,
nettle, raspberry (see above), vervain (70).
The MHRA also warns that some herbal teas contain laxatives such as senna, frangula and cascara
(70). This is of note in pregnancy because the effects of these herbs may generate contraction of
uterine smooth muscle.
Suspected adverse reactions (including congenital abnormalities) associated with maternal use of
herbal or complementary medicines should be reported to the MHRA and CHM via the yellow card
reporting system.
Practical Advice
Herbs that are commonly used in cooking would not be expected to be harmful during pregnancy in
the quantities usually contained in foods (45). However, even culinary herbs such as sage, garlic and
turmeric may be associated with risks if they are taken in large doses or concentrated forms (45). The
following advice may be of use to women planning to take herbs at medicinal doses:
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Avoid medicines (herbal or conventional) during pregnancy unless they are considered to be
essential.
Seek the advice of a healthcare professional (midwife, doctor or pharmacist) if you are
considering taking herbal medicines. If you decide to take herbal medicines during pregnancy,
ensure that the healthcare professionals involved in your antenatal care are aware of any herbal
medicines that you are taking, or changes in your medication.
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If you do decide to take herbal medicines, choose products from a reputable source and follow
the manufacturer’s instructions, especially the dosage advice.
Remember that most herbal medicines have often not undergone rigorous testing before being
made available. There might be little or nothing known about their effects during pregnancy.
Therefore, it is important that you tell your healthcare provider if you feel unwell when taking these
products.
Herbal medicines might have contaminants such as heavy metals, pesticides or conventional
medicines, some of which could be harmful to your unborn child.
Herbal medicines have the potential to interact with any conventional medicines you are taking,
which may make you feel unwell and effect how well your conventional medicine works.
It is important for healthcare professionals to take into consideration why a woman wishes to take an
herbal medicine. Undiagnosed illness that remains untreated by conventional methods might result in
maternal and foetal toxicity.
Healthcare professionals can contact the UK Teratology Information Service on 0844 892 0909 for
assistance in making a patient-specific risk assessment where exposure to herbal medicines has
occurred.
Summary
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Recent surveys in the UK suggest that many women in the United Kingdom use herbal
medicines during pregnancy.
In general, herbal medicines should be avoided by pregnant women.
Herbal medicines are not necessarily safe alternatives to conventional medicines during
pregnancy. Their constituents are likely to have pharmacological activity and they might
possess toxic constituents. Contamination cannot be ruled out and different products often
vary with regard to the concentration and source(s) of their constituent herbs.
The way in which an herbal medicine is administered might affect its safety, e.g. as a tea or
concentrated extract, orally or topically.
Possible interactions with any conventional treatment should be taken into account.
Women who wish to take herbal products during pregnancy should consult a healthcare
professional when considering the risks and benefits involved.
Healthcare professionals should consider why a woman wishes to take an herbal medicine.
Undiagnosed illness that remains untreated by conventional methods might result in maternal
and foetal toxicity.
Any herbal medicines taken should be from a reputable source and taken at the
recommended dosage.
Suspected adverse reactions (including congenital abnormalities) following maternal
exposure to an herbal or complementary medicine should be reported via the yellow card
system.
Healthcare professionals can contact the UK Teratology Information Service for assistance in
making a patient-specific risk assessment where exposure to herbal medicines has occurred.
Limitations
The information above is predominantly concerned with the safety, rather than the efficacy of herbal
medicines during pregnancy. It is not an exhaustive list and exclusion from this Q&A does not indicate
safety. Only limited relevant information on the safety of herbal medicines in pregnancy is available at
present. Herbal products vary considerably with regard to their concentration, potential toxicity,
constituents and the sources of their constituents.
References
(1) Bishop JL, Northstone K, Green JR, et al. The use of complementary and alternative medicine in
pregnancy: Data from the Avon Longitudinal Study of Parents And Children (ALSPAC).
Complement Ther Med. 2011;19:303-10.
(2) Holst L, Wright D, Haavik S, et al. The use and user of herbal medicines during pregnancy. J
Altern Complem Med. 2009; 15: 787-92.
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(3) Nordeng H, Bayne K, Havnen GC, et al. Use of herbal drugs in pregnancy among 600
Norwegian women in relation to concurrent use of conventional drugs and pregnancy outcome.
Complement Ther Clin Pract. 2011; 17: 147-51.
(4) Forster DA, Denning A, Wills G, et al. Herbal medicine use during pregnancy in a group of
Australian women. BMC Pregnancy Childbirth 2006; 6: 21. Published online 2006 June 19. DOI:
10.1186/1471-2393-6-21.
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Quality Assurance
Prepared by
Sara Arthur, Welsh Medicines Information Centre, University Hospital of Wales
(Based on previous work by Alex Bailey, Welsh Medicines Information Centre, University Hospital of
Wales)
Date Prepared
23 February 2017
Checked by
Gail Woodland, Welsh Medicines Information Centre, University Hospital of Wales
Available through Specialist Pharmacy Service at
www.sps.nhs.uk
Medicines Q&As
Date of check
11 March 2017
Search strategy
1. Embase ([herbal medicine OR medicinal plant] AND [pregnancy OR congenital malformations/si]
2. Medline ([exp plants, medicinal OR exp drugs, Chinese herbal OR phytotherapy OR exp
angiosperms] AND [pregnancy outcome OR exp abnormalities, drug-induced]
3. In-house database (“herbal medicines” AND pregnancy)
4. NHS Evidence (“herb/herbal AND pregnancy”)
5. Micromedex (pregnancy) (herbal medicine name)
6. Herbal medicines online (herbal medicine name)
7. Briggs online (herbal medicine name)
8. Natural Medicines (herbal medicine name)
9. United Kingdom Teratology Information Service (UKTIS), Regional Drug and Therapeutics
Centre, Newcastle upon Tyne
10. Cochrane
11. NICE (herbal medicine name)
Available through Specialist Pharmacy Service at
www.sps.nhs.uk