Complementary Therapies in Clinical Practice 17 (2011) 147e151

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Complementary Therapies in Clinical Practice

journal homepage: www.elsevier.com/locate/ctcp

Use of herbal drugs during pregnancy among 600 Norwegian women in relation
to concurrent use of conventional drugs and pregnancy outcome
Hedvig Nordeng a, b, *, Karen Bayne a, c, Gro Cecilie Havnen a, Berit Smestad Paulsen c
a
Department of Pharmacy, School of Pharmacy, University of Oslo, Oslo, Norway
b
Division of Mental Health, National Institute of Public Health, Norway
c
Department of Pharmacognosy, School of Pharmacy, University of Oslo, Oslo, Norway

a b s t r a c t
Keywords: Purpose: The purpose of this study was to investigate the use of herbal drugs by pregnant women in
Herbal drug use relation to concurrent use of conventional drugs, delivery, and pregnancy outcome.
Pregnancy outcome
Method: 600 women at Stavanger University Hospital Norway were interviewed using a structured
Birthweight
Complementary and alternative medicine
questionnaire within five days after delivery. Medical birth charts were reviewed with respect to
pregnancy outcome.
Results: In all, 39.7% of the women reported having used herbal drugs during pregnancy, most commonly
ginger, iron-rich herbs, echinacea and cranberry. Although 86.3% of the women reported having used
conventional drugs during pregnancy there were few potential interactions between herbal drugs and
conventional drugs. There was a significant association between the use of iron-rich herbs during
pregnancy and high birthweight, and use of raspberry leaves and caesarean delivery.
Conclusion: Use of herbal drugs is common during pregnancy and indicates a need for documentation
about their safety in pregnancy.
Ó 2010 Elsevier Ltd. All rights reserved.

1. Introduction prevalence of use was extremely low (0.7%), and it might not be
random who reported such use. Also, studies that aimed primarily
Several Western studies have documented that the use of herbal to investigate the effect of ginger on nausea and vomiting in
drugs during pregnancy is relatively frequent.1e11 European studies pregnancy together included close to 700 exposed pregnancies
from the United Kingdom (56%),1 Italy (48%)2 and Norway (36%)3 without reporting increased risks of negative pregnancy outcome.14
showed that herbal drugs are widely used for pregnancy-related Echinacea was the focus of one prospective controlled study, where
complaints and acute illnesses. The prevalence of use of herbal no increased rates of major malformations above the baseline rate
drugs during pregnancy ranged from 4% to 45%4e8 in the United of 1e3% were reported (n ¼ 206 women).15 Use of flax during the
States and from 12% to 62%9e12 in Australian studies. Herbs such as last two trimesters of pregnancy was shown to increase the risk of
ginger (nausea), echinacea (common cold), cranberry (urinary tract prematurity (adjusted odds ratio ¼ 3.91; 95% CI 1.16e13.14) in
bothers) and raspberry leaf (as a uterotonic) were found to be the a recently published case-control study. 16 For most herbs, however,
most commonly used by pregnant women in the Western data on safety during pregnancy are limited to case reports, animal
world.1e12 Most of these studies focused on describing the preva- studies or theoretical reflections.17 In recent years, attention has
lence of use and factors related to herbal drug use during preg- been focused on potential interactions between herbal drugs and
nancy. Very few studies related use of herbal drugs to pregnancy conventional drugs. For example, ginger may interact with acid
outcome and to concurrent use of conventional drugs. In one study inhibiting drugs,17 and both of these are used frequently by preg-
based on the Swedish Medical Birth Registry, no increased risk for nant women.
negative pregnancy outcome was found after exposure to herbal
drugs early in pregnancy.13 However, as herbal medications are not
systematically recorded in the Swedish Medical Birth Registry, the 2. Aims

The aim of this study was to investigate the use of herbal drugs
* Corresponding author at: Department of Pharmacy, School of Pharmacy,
University of Oslo, P.O. Box 1068 Blindern, N-0316 Oslo, Norway. Tel.: þ47 22 85 66
by pregnant women in relation to concurrent use of conventional
04; fax: þ47 22 85 44 02. drugs, delivery, and pregnancy outcome. To date few studies have
E-mail address: h.m.e.nordeng@farmasi.uio.no (H. Nordeng). investigated the relationship of such use among pregnant women.

1744-3881/$ e see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.ctcp.2010.09.002
148 H. Nordeng et al. / Complementary Therapies in Clinical Practice 17 (2011) 147e151

3. Methods significant variables were retained in the final linear regression

model. Specific models were made for ginger, iron-rich herbs,
3.1. Study population echinacea, cranberry, raspberry leaves and chamomile. Logistic
regression analysis was used to test for associations between herbal
All women having delivered at the Stavanger University Hospital drug use, conventional drug use, maternal age, parity, education,
during the study period November 2003eMarch 2004 were eligible marital status and delivery characteristics. We used the Statistical
for the study. Stavanger University Hospital covers a population of Package for Social Sciences (SPSS), version 16.0.1.
approximately 300 000 inhabitants in the west of Norway, of whom
approximately 60 000 are women of reproductive age. Each year 4. Results
there are approximately 4000 deliveries at the hospital. The eligible
women were given written and oral information about the study 4.1. Demographics
before their written informed consent was obtained. Permission to
review the woman’s hospital chart was also requested. Women In all, 648 women had to be invited to participate in the study
who did not understand or speak Norwegian were not invited to before 600 women agreed to take part. Thus, the participation rate
participate to avoid misunderstandings due to language difficulties was 92.6%. The most common reasons given for declining to partic-
and because herbal drug use among these women might not be ipate were being tired, needing rest or having visitors. Participants
representative for Norwegian parturients. were similar to Norwegian parturients (NP) in general with respect to
age (mean age 29.1 years among the study women (SW) vs. 29.5 years
3.2. Data collection NP), parity (primiparous: 41.2% SW vs. 40.8% NP) and marital status
(married or cohabiting: 95.3% SW vs. 94.1% NP) except that tertiary
Each interview was conducted using a structured questionnaire education was over-represented.18e20 The percentage of women with
during the woman’s postnatal stay in the hospital. Before asking a tertiary education was 53.5% among the women in the study and
about use of herbal drugs we explained the definition of the herbal 38.2% among women aged 20e49 years in the general population.20
drugs examined in the study. We defined a herbal drug as any Socio-demographic characteristics were similar among users
remedy produced from a herb or herbs with the intent to cure or and non-users of herbal drugs, except for education level. A higher
prevent illness, to alleviate symptoms or to gain better health. proportion of women using herbal drugs during pregnancy had
Foods or drinks flavoured with herbs (i.e. ginger biscuits) or spices tertiary education (59.2% vs. 49.7% among non-users, p ¼ 0.006).
were not considered herbal drugs. We also specifically asked about
the use of homeopathic remedies. In addition, the participants were 4.2. Use of herbal drugs during pregnancy
asked to report use of conventional drugs during pregnancy. After
the open-ended questions, we asked disease-oriented questions Overall, 39.7% of the women reported having used herbal drugs
(pregnancy-related complaints) and questions about specific herbs during pregnancy (average 1.6 herbal drugs). Table 1 presents the
(echinacea, Floradix FormulaÒ (iron-rich herbal extract), ginger, herbal drugs most commonly used and the reported reasons for use.
chamomile, valerian, cranberry, horsetail, elderberry, St. John’s wort) Use during the first trimester was reported by 24.3% of the women.
to help the women recall any use. The choice of herbs asked about Half of the women (50.4%) used the herbal drug for longer than 14
was based on the results of a previous study.3 The women were also days, and sporadic use was reported by 26.5%. Homeopathic drugs
asked who had recommended the use of herbal drugs in preg- were used by 4.3% of the women, most commonly to prepare the
nancy; several informers could be mentioned. When conventional body for labour and for better wound healing after delivery. Previous
drugs and herbal drugs were used concomitantly, potential use of herbal drugs prior to pregnancy was reported by 61.8% of the
drugeherb interaction was assessed according to reference litera- women. Among the women who had breast-fed previously, 37.3%
ture.17 The socio-demographic characteristics recorded were age, reported use of herbal galactagogues in a previous breast-feeding
marital status, parity and education level. During the interview the period.
woman was also asked the infant’s birthweight, gestational age and
use of pain relief during delivery (including analgesics and 4.3. Conventional drug use and potential interactions
acupuncture). Each interview lasted approximately 20 min. All data
were handled and stored anonymously. Most of the study participants (86.3%) reported having used
In addition to the interview, we reviewed each woman’s medical conventional drugs during pregnancy (range: 0e7, mean 2 drugs,
chart. The medical chart included all information routinely recorded
before, during and after delivery by health care professionals. Infor- Table 1
Use of herbal drugs during pregnancy (n ¼ 600).
mation before delivery included maternal disease and medication use
during pregnancy. Information about the delivery included type of Herbal drug Women using herbal Most frequent reasons
delivery, use of acupuncture during delivery and use of pharmaco- drugs in pregnancy, n (%) for use
logical analgesics during delivery. Information about pregnancy Total use of herbal 238 (39.7)
outcome included birthweight, gestational age and presence of drugsa
Ginger 67 (11.2) Nausea
neonatal and/or maternal complications after delivery. Information Iron-rich herbs 49 (8.2) Prevent anaemia
from the mother was crossed-checked with information from her Echinacea 45 (7.5) Cold, flu symptoms
medical chart. Cranberry 37 (6.2) Urinary tract disorders
Raspberry leaves 34 (5.7) Prepare uterus for labour
Chamomile 29 (4.8) Sedative, relaxant
3.3. Data analysis
Various herbal teas 17 (2.8) Sedative, gastrointestinal
disorders
Student’s t-test was used to test for difference of means. Pear- Aloe vera 16 (2.7) Rash, itching
son’s chi-square test was used to test for differences in proportions. Elderberry 15 (2.5) Cold, flu symptoms
Linear regression analysis was used to test for associations between Other herbs 70 (11.7) Various

herbal drug use, conventional drug use, maternal age, parity, a

Some women used several herbal drugs. The total number of herbal drugs used
education, marital status, gestational length and birthweight. Only was 379.
 H. Nordeng et al. / Complementary Therapies in Clinical Practice 17 (2011) 147e151 149

Table 2
Overview of the most common conventional drugs used during pregnancy among users and non-users of herbal drugs during pregnancy.a.

Conventional drug use, n (%) Conventional drug use among Conventional drug use among p-Valuec
users of herbal drugs, n (%) non-users of herbal drugs, n (%)
Total number of women 600 (100.0) 238 (100.0) 362 (100.0)
Conventional drugs, totalb 518 (86.3) 216 (90.8) 302 (83.4) 0.011
Analgesics 352 (58.7) 156 (65.5) 196 (54.1) 0.006
Drugs for heartburn 218 (36.3) 109 (45.8) 109 (30.1) <0.001
Decongestant nasal spray 213 (35.5) 104 (43.7) 109 (30.1) 0.001
Anti-infectives 129 (21.5) 62 (26.1) 67 (18.5) 0.028
Drugs for constipation 68 (11.3) 39 (16.4) 28 (7.7) 0.002
Antihistamines 58 (9.7) 26 (10.9) 32 (8.8) 0.398
a
Only drug categories used by more than 50 women are presented.
b
Excluding vitamins and iron tablets. Several women used more than one conventional drug.
c
Pearson’s chi-square test.

excluding vitamins and iron tablets) (Table 2). Vitamins and iron Mean birthweight was 155 g (SD 47 g) higher among the users of
tablets were used by 89.2% and 37.0% of the women, respectively. herbal drugs during pregnancy (3663 g vs. 3508 g) (p ¼ 0.001). Sub-
The most commonly used conventional drugs were analgesics analyses on the most commonly used herbs (ginger, iron-rich herbs,
(58.7%), drugs for heartburn (36.3%), nasal decongestants (35.5%), echinacea, cranberry, raspberry leaves and chamomile) revealed that
anti-infectives (21.5%), drugs for constipation (11.3%) and antihis- this finding was mainly related to the use of iron-rich herbs (mean
tamines (9.7%) (Table 2). Women who used herbal drugs during birthweight was 3793 g (SD 567 g) vs. 3550 g (SD 575 g) among non-
pregnancy used conventional drugs to a larger extent than women users of iron-rich herbs, p ¼ 0.005). Linear regressions analyses
who did not use herbals did (90.8% vs. 83.4%, p ¼ 0.011) (Table 2). showed that use of iron-rich herbs remained an independent factor
\For 15 women (2.5%) the use of interacting herbs and conven- associated with increased birthweight after controlling for gesta-
tional drugs occurred concurrently within the same trimester. These tional length and maternal age (Table 4). In contrast, there was no
were: ginger and acid suppressants (8 cases; may decrease the effect significant association between use of conventional drugs and
of acid suppressant17), chamomile and psychotropic drugs (4 cases; birthweight.
may increase CNS effects17), iron-rich herbs and acid suppressants (2 There was also a significant association between the use of rasp-
cases; may result in mutual decreased effect17), dandelion and berry leaves and caesarean delivery (23.5% vs. 9.1% among women
furosemid (1 case; may increase the diuretic effect17). with no use of herbal drugs, crude odds ratio ¼ 3.18; 95% CI 1.37e7.38).
The use of herbal drugs was most frequently recommended by This association remained significant even after controlling for
family or friends (34.0%) or was started at the woman’s own maternal age, parity, marital status, education and conventional drug
initiative (29.8%). Health care personnel had recommended the use use (adjusted odds ratio ¼ 3.47; 95% CI 1.45e8.28).
of herbal drugs for 19.3% of the women, mainly the use of one iron-
rich herbal preparation (Floradix FormulaÒ). Recommendations in
advertising (19.3%) and by personnel in stores selling herbal 5. Discussion
products (13.0%) were also common.
There is a fairly substantial body of literature describing herbal
drug use during pregnancy. However, to our knowledge, few studies
4.4. Pregnancy outcome and delivery have been specifically designed to describe pregnant women’s use
of herbal drugs in relation to pregnancy outcome and concomitant
Except for birthweight, there were no significant differences drug use. An interesting finding of this study was that women using
between users and non-users of herbal drugs in general in any of herbal drugs during pregnancy used conventional drugs to a larger
the pregnancy outcomes investigated (Table 3). extent than women who did not use herbals did (91% vs. 83%). An
explanation may be a difference in morbidity (for example, infec-
tions) and/or pregnancy-related complaints between users and
Table 3 non-users of herbal drugs. Also, some women may be more willing
Pregnancy outcome and delivery according to use of herbal drugs during pregnancy.
to self-medicate themselves in general, with both over-the-counter
Women with Women without p-Valuea drugs and herbal drugs. It is worth noting that herbal drugs seem to
herbal drug use, herbal drug use,
n ¼ 238 n ¼ 362
Pregnancy outcome
Table 4
Birthweight in grams, 3663 (570) 3508 (576) 0.001
Associations between birthweight and gestational age, parity and use of iron-rich
mean (SD)
herbs in pregnancy using linear regression analyses, R2 (adjusted) ¼ 0.314.a.
Gestational length in days, 277 (12) 275 (13) 0.085
mean (SD) Adjusted b (95% CI) p-Value
Neonatal complications 26 (10.9) 39 (10.8) 0.954
Constant 3543.4 g
requiring transfer
Gestational length (days) 24.2 (21.1e27.4) <0.001
to intensive care units (%)
Parity (number of 0 (reference)
Delivery characteristics previous children) 1 138.9 (53.6e224.1) 0.001
Acupuncture at delivery (%) 69 (29.0) 88 (24.3) 0.202 Iron-rich herbs No (reference)
Pharmacological analgesics 179 (75.2) 281 (77.6) 0.494 Yes 147.0 (5.8e288.3) 0.042
at delivery (%) a
Only variables significantly associated with birthweight were retained in the
Caesarean section (%) 25 (10.5) 33 (9.1) 0.573
final linear regression model. In the original model maternal age, marital status,
a
Student’s t-test to test for difference of means, Pearson’s chi-square test for education, caesarean section, use of iron tablets, and use of conventional drugs were
difference between dichotomous variables. investigated as potential confounding factors.
150 H. Nordeng et al. / Complementary Therapies in Clinical Practice 17 (2011) 147e151

have been used complementary to conventional drugs as the use of herbal drugs, supporting that previous positive personal experience
conventional drugs was high among both users and non-users of is an important determinant for herbal drug use during pregnancy.
herbal drugs. During delivery, however, women using herbal drugs However, the finding that herbal drugs were used frequently in
tended to opt for acupuncture instead of pharmacological analge- pregnancy with little involvement of health care personnel suggests
sics for pain relief. This might reflect a greater inclination towards that there should be more focus on this topic during maternity care.
a “natural” delivery and complementary and alternative therapy, Health care personnel should be encouraged to have an open
although the findings were not significant. discussion about the pros and cons of herbal drugs and should have
The fact that there were few cases of potential herbaledrug knowledge about the safety and efficacy of the herbs most
interactions was reassuring. However, knowledge of new, previ- commonly used during pregnancy.
ously unknown herbedrug interactions is rapidly increasing. As This study has both strengths and limitations. The limitations
a consequence, concomitant use warrants continuous attention on include retrospective reporting that may underestimate the actual
the part of both health care personnel in general and prescribing use. There might be differential reporting among women according
physicians. to whether the infant was healthy or not. Also, we did not have
There are several different possibilities for the increased birth- information about potentially important confounding factors, such
weight observed after use of iron-rich herbs. This could be due to as the woman’s body mass index prior to pregnancy and smoking
a positive nutritional effect on the mother and child, resulting in status. The strengths include a thorough personal interview focused
increased birthweight. Another hypothesis is that the finding is on detecting herbal drug use and a high response rate. The clear
related to the characteristics of women using iron-rich herbs. A advantage of the personal interviews is that they permit to uncover
possibility is that they smoke cigarettes to a lesser degree. It is well possible misunderstandings, for example what we consider a herbal
known that cigarette smoking interferes with the supply of oxygen drug. The results must be interpreted with these considerations in
and other nutrients to the foetus and may interfere with foetal mind.
growth.21 Forester et al. found a lower percentage of smokers
among users of herbal drugs,10 whereas Holst et al. did not.1,13
6. Conclusion
Unfortunately, we did not ask about smoking or alcohol drinking
habits during pregnancy due to the delicate nature of these ques-
Use of herbal drugs during pregnancy occurred frequently
tions. Further studies are needed to pursue this possibility. Finally,
during pregnancy, and often in addition to conventional drugs.
we cannot exclude that some iron-rich herbs may have a direct
Potential interactions between herbs and conventional drugs
effect on foetal growth.
occurred rarely. Use of iron-rich herbs was associated with
The association between use of raspberry leaf and increased risk
increased birthweight, and use of raspberry leaves prior to delivery
of caesarean section has not previously been reported and may be
was associated with an increased risk of caesarean delivery. The
of clinical importance. The most commonly reported reasons for
finding in this study indicates an increased need for further studies
use of raspberry leaves in pregnancy is to strengthen, tone or
about the safety of the most common herbs used in pregnancy. To
prepare the uterus and cervix, induce, ease or shorten labour and to
meet the needs of pregnant women, it is necessary for health care
relieve nausea.22 It may be that the women using raspberry leaves
personnel to have knowledge about herbal drugs and to be willing
have to a greater extent underlying conditions that increase the risk
to discuss their use with pregnant women.
of a caesarean section and that the finding is due to confounding by
indication. We can, however, not rule out the possibility that there
may be active substances in raspberry leaves that act directly on the Acknowledgements
pregnancy uterus in a negative way. Both human in vitro and animal
studies with raspberry leaf extracts have shown a possible inhibi- This work was supported by the Foundation for Promotion of
tory or relaxant effect on uterine smooth muscle contractions.22 Norwegian Pharmacies. We wish to thank all the women who
However, in one controlled study among 97 pregnant women participated in the study. We would also like to thank the maternity
using raspberry leaf tablets (2  1.2 g a day) there was no difference ward staff at Stavanger University Hospital, Norway, and especially
in emergency caesarean rate or gestational length.23 Our finding O. Hompeland and S.M. Lichtenberg.
should be explored in future investigations where information
about the reason for caesarean section and the amount, timing and Conflict of interest statement
duration of raspberry leaf intake is included, especially as the use of The authors have no conflict of interest.
raspberry leaves is relatively common. It has recently been shown
that 25% of 578 women in a British hospital clinic had used rasp-
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