Hindawi Publishing Corporation
Obstetrics and Gynecology International
Volume 2012, Article ID 796590, 5 pages
Adherencewith DrugTherapy in Pregnancy
Child Health Research Institute, Departments of Pediatrics and Medicine, Children’s Hospital, London Health Sciences Centre,
The University of Western Ontario, London, ON, Canada N6C 2V5
Correspondence should be addressed to Doreen Matsui, email@example.com
Received 15 September 2011; Accepted 12 October 2011
Academic Editor: Gideon Koren
Copyright © 2012 Doreen Matsui. This is an open access article distributed under the Creative Commons Attribution License,
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Available information suggests that nonadherence with medication is a common problem in pregnant women. Not taking
prescribed drugs may have potentially negative consequences as patients may not achieve their therapeutic goal. In addition to
the many factors that may influence medication-taking behaviour in the general population, unique challenges are encountered
in pregnant women as both maternal health and fetal well-being must be considered. On the one hand, pregnant women may be
motivated to keep their underlying disease under control, while, on the other hand, fear and anxiety regarding the potential
harmful effects of their medication on their unborn child may result in poor adherence with needed medication. Providing
evidence-based information,ideally preconceptually, regarding theeffects oftheir medicationduringpregnancy maybe important
in avoidingmisperceptions that lead to nonadherence.
Advances in drug therapy have resulted in efficacious treat-
ments being available for many acute and chronic medical
conditions; however, it is well recognized that “Drugs don’t
adherence, a term which is often used interchangeably with
compliance, as the extent to which a person’s behaviour-
changes, corresponds with agreed recommendations from a
health care provider . Unfortunately, nonadherence with
medication regimens is not uncommon with the potential
negative consequences of failure to achieve the desired treat-
ment goal. Many factors may play a role in whether patients
comply with their therapy and pregnancy may present
uniquechallenges as fetal well-being must also be considered
overview of medication adherence in general and then will
focus on some of the issues related to medication-taking
behaviour during pregnancy.
Nonadherence with drug therapy may take many forms with
delayed or omitted doses being the most common errors.
Discontinuation of medication administration prior to com-
pletion of the course is also common. Adherence is gen-
erally measured over a specified period of time and often
reported as the percentage of the prescribed doses of med-
ication actually taken by the patient . In a meta-analysis
of 569 studies, reported adherence to medical treatment
ranged from 4.6% to 100% with a median of 76% and
an overall average of 75.2% . Drug compliance may
be of particular concern with chronic conditions as therapy
is often long term and patients without symptoms may be
required to take medication to prevent later complications
without any immediate benefits noted. Contrary to what
one might think seriousness of the underlying medical
condition does not ensure compliance, as has been shown
with both cancer and organ transplant therapy [5–9]. Not
taking one’s medication is not without clinical implica-
tions given the relationship between inadequate adherence
and unfavourable disease outcome. In a meta-analysis of
21 studies, good adherence with drug therapy was associ-
ated with lower mortality compared with poor adherence
(odds ratio 0.56, 95% CI 0.50–0.63) . Other conse-
quences of nonadherence may include inappropriate alter-
ation in treatment regimens ordosageadjustments with sub-
sequent toxicity, unnecessary investigations, and increased
2Obstetrics and Gynecology International
Nonadherence with medical therapy is a complex multi-
faceted problem involving patient and family factors, disease
factors, physician factors, and regimen factors . Unfor-
tunately, none of these factors have been found to reliably
predict which patients will or will not take their prescribed
medication. Various methods are available to assess adher-
ence; however, all have advantages and disadvantages and
no universally accepted gold standard exists. The accuracy
of self-reporting is often questioned, in particular when the
suggestion is that compliance is good. Pill counts may also
underestimate adherence as patients “dump” their pills prior
to their clinic visit. Measurement of drug levels, available for
a limited number of medications, only reflects recent inges-
tion. Electronic monitors that provide continuous “real-
time” measurement can provide information on temporal
dosing patterns and allow correlation with breakthrough
It is important to have a high index of suspicion in order
toidentifyearly thosenoncompliant patientswho havefailed
to attain their treatment goal and who may benefit from
more targeted support and adherence-enhancing strategies
that may include educational and behavioural approaches.
Potential barriers to adherence should be identified. No
single intervention has been shown to be effective across
all patients, conditions, and settings . In a review of
interventions for enhancing medication adherence less than
one-half of the interventions tested were associated with
only 29 of 93 interventions reported statistically significant
improvements in treatment outcomes. The common theme
was more frequent interaction with patients with attention
to adherence .
Despite the ample evidencein the literature of the important
role of adherence with drug therapy in influencing treatment
outcomein thegeneralmedical population,there isa relative
paucity of studies that have focused specifically on whether
pregnant women do or do not take their medication. Much
of the research addressing medication compliance during
pregnancy has been undertaken in women with HIV infec-
tion although there are scattered reports in other medical
The information available suggests that nonadherence
with prescribed drugs is also a problemin the pregnant pop-
ulation. 39% of women who received one or more prescrip-
tionsreported noncomplianceduring pregnancy when inter-
viewed within two weeks after delivery. Reasons included
doubtsabout the use of the drug during pregnancy, expected
side effects, disappearance of the complaints for which the
drugs were prescribed, or the complaint persisted notwith-
standing drug therapy. Approximately 40% of women had
had one or more questions about drugs during their preg-
nancy with safety being the issue that raised most questions
Similarly, using data from the North Jutland Prescription
Database and from theDanish National Birth Cohort survey,
the overall compliance rate with prescription drugs in preg-
nant women was estimated to be 43% . In the outpatient
clinics of an Australian hospital, medication nonadherence
was reported by 59.1% of pregnant participants with a
chronic health condition. Nonadherence was mainly nonin-
tentional, with forgetting to take medication being the most
common reason. In this study, the majority of participants
had some concernsabout using any medication during preg-
3.1. Adherence with HIV Medications. Poor adherence with
HIV treatment regimens may be a determinant of virologic
failure, emergence of drug resistant virus, and disease pro-
gression .Inadditiontotreating themother’sunderlying
disease, antiretroviral treatment in pregnant women also
aims to prevent vertical perinatal HIV transmission to the
child [18, 19]. Highly active antiretroviral therapy (HAART)
has reduced mother-to-child transmission rates to around 1
to 2% in resource-rich countries . Lack of medication
adherence in pregnant women with HIV infection may
interfere with these goals. Medication nonadherence was a
significant factor associated with suboptimal viral suppres-
sion at thetime ofdelivery (definedbyHIVviral load ≥1000
copies) in addition to baseline viral load ≥10,000 copies per
Studies have shown that HIV-infected pregnant women
have greater adherence with antiretroviral drugs than non-
pregnant women [22–24]. However, adherence rates during
pregnancy are still not optimal and have been reported to be
between 43.1% and 80% using various methods of compli-
ance assessment [22–28]. Better compliance with prescribed
medications during pregnancy may be related to concern
for the baby’s health [24, 29]. In the Women and Infant
Transmission Study, 90% of women who reported improved
adherence with their HIV medications during pregnancy
stated that their baby’s health was the primary reason .
Dosing regimen has also been shown to be important as
less than 6 pills per day and up to two doses per day were
associated with better adherence . Similarly, pregnant
women who were prescribed zidovudine only once or twice
dailydemonstrated significantly higheradherencethan those
prescribed this medication three to five times per day
. Social support, especially from family members, has a
positive influence on medication-taking behaviour .
Barriers to good adherence with antiretroviral therapy
include being preoccupied with other issues and hectic life-
styles  as well as illicit drug use [27, 28]. Untreated de-
pression during pregnancy is also associated with nonadher-
enceto HIVtreatment regimens and treatment ofdepression
may improve medication adherence . As poor adherence
with antiretroviral drugs during pregnancy may predict
nonattendance at infant followup , identifying women
who are having troubletaking their medication is important.
3.2. Adherence with Medications Prescribed for Other Condi-
tions. As in the general population less than perfect adher-
ence with medication taking has been demonstrated in pa-
tients with other medical conditions, examples of which will
Obstetrics and Gynecology International3
3.2.1. Epilepsy. Incomplete compliance with anticonvulsant
medication was reported by 62.3% (157/252) of pregnant
women with epilepsy . Hair analysis was undertaken in
26 pregnant women taking carbamazepine or lamotrigine
with four patients (15%) showing declines in drug concen-
tration in the more proximal segments suggesting a change
in drug-taking behaviour. Resultswere interpreted to suggest
that these women had discontinued their medication during
3.2.2. Asthma. For three categories of asthma severity before
pregnancy (intermittent, mild persistent, and moderate/se-
vere), mothers whose medication use fell below the recom-
mended guideline experienced more severe asthma during
pregnancy than women using their recommended medica-
tion . In an online survey, 39% of women who have been
pregnant reported that they had discontinued or reduced
their asthma medication during pregnancy, a third having
done so without discussion with a physician. Of potential
significance in managing these patients, 40% ofwomen indi-
cated that they would be more likely to continue taking their
asthma medication during pregnancy if their obstetrician
alone recommended it . 40% of pregnant asthmatic sub-
jects reported nonadherence to inhaled corticosteroid medi-
to ICS decreased to 21%  which is important to note as
lack of appropriate treatment with inhaled corticosteroids is
associated with exacerbations of asthma during pregnancy
3.2.3. Inflammatory Bowel Disease. Although studies have
suggested that exacerbations of inflammatory bowel disease
(IBD) during pregnancy may worsen pregnancy outcomes,
84%offemalepatientswith IBDreported concernsthattheir
IBD medications would harm their pregnancy while only
19% reported concerns about the effect of active IBD on
pregnancy . In Crohn’s disease 67% (37/55) of women
reported adherence to medical treatment during pregnancy
 while in ulcerative colitis 60% (37/62) of women re-
ported adherence . With both conditions, reasons stated
for nonadherence included quiescent disease and fear of
negative effects on the fetus [39, 40].
3.2.4. Nicotine Replacement Therapy. Adherence to nicotine
replacement therapy (NRT) is low among pregnant smokers.
Fish et al. found that overall only 29% of 104 women used
NRT for the recommended 6 weeks and 41% used NRT as
directed in the first 48 hours after a quit attempt .
adherence in the nonpregnant population, there are unique
influences that may play a role in pregnant women. On the
one hand, pregnant women may be motivated to take their
medication for the well-being of their baby, mindful of the
potential negative fetal consequences of untreated maternal
disease. On the other hand, it has been demonstrated that
women may not take their medication due to concerns
regarding potential adverse fetal effects [14, 39, 40, 42]. In
some cases this fear may be justified based on known ter-
atogenic effects; however, in many cases medications have
not been demonstrated to be harmful. It has been shown
that pregnant women tend to overestimate the risks asso-
ciated with drug use during pregnancy. Most women who
completed an internet survey were able to correctly identify
that the general risk of malformation is ≤5%; however,
they overestimated the teratogenic risk associated with many
drugs during pregnancy .
If women with inadequately controlled disease due to inade-
quate adherence with drug therapy are identified, they may
be targeted for evidence-based counselling to correct their
misperceptions, allay their fears, and hopefully improve
medication-taking behaviour . In addition, it may be
by proactively addressing the pregnant woman’s concerns
about the safety of medications. Ideally, with chronic drug
therapy this counselling may occur as part of prepregnancy
planning. Survey studies have shown that pregnant women
feel they need information about the use of drugs during
pregnancy [14, 42]. Media and other sources may provide
misleading information provoking anxiety amongst preg-
nant women . Given the overestimation of risk, the dis-
cussion should include,if available,evidence-based informa-
tion on the effects of the medication’s use during pregnancy
allowing the pregnant women to make an informed decision
should focus on the important role of good medication
adherence for the health of both the mother and fetus.
Counselling by teratogen information services may play
a rolein influencingmedication-takingbehaviour.After
counselling by Motherisk, a Canadian teratogen information
service, 61.1% (22/36) of pregnant women who had discon-
tinued their antidepressant or benzodiazepine medication
restarted their medication within a few days . Health
care workers, such as obstetricians and family physicians,
are uniquely positioned to not only monitor adherence but
to encourage consultation with drug information services to
dispel misconceptions about the risks of medications to the
A meta-analysis of studies of directly observed therapy
of highly active antiretroviral therapy (DOT-HAART) found
that DOT-HAARTrecipients were more likely to achieve un-
detectable viral load and HAART adherence of greater than
or equal to 95% . A similar approach has been suggested
for pregnant women. The third trimester of pregnancy may
present an opportunity for the use of directly observed
HAART to achieve virologic suppression for prevention of
mother-to-child transmission of HIV . Using a simula-
tion model, use of DOT in women receiving HAART in 3rd
trimester was associated with a relative risk of mother-
to-child HIV transmission of 0.39 relative to conventional
4Obstetrics and Gynecology International
HAART. It was projected to be highly cost-effective, averting
the downstream medical costs associated with pediatric HIV
infection . All but one of 17 Latina pregnant and post-
partum women positively evaluated a proposed hypothetical
modified DOT program  suggesting that at least some
women would be accepting of this approach.
Surprisingly, although it is generally accepted that the main-
tenance of good health of the pregnant women through the
treatment of underlying maternal medical conditions is of
potential benefit to the unborn fetus, medication nonadher-
enceisa commonlyencounteredproblemin thispopulation.
As in the nonpregnant patient the problem is complex with
many factors playing a role; however, additional issues such
as the potential effects of the medication on the baby may
affect the mother’s decision-making process. Ideally, poor
education of the mother although it is unlikely that this
approach will be effective in all cases and solve all problems.
More research to provide the evidence-based information
regarding the effects of drugs during pregnancy, in order to
avoidmisperceptions, as well asbetterknowledge translation
is needed. Identification and evaluation of other effective
strategies to improve medication adherence in pregnant
women who are already not taking their medication will also
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