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Review Article pISSN 2383-9309❚eISSN 2383-9317
J Dent Anesth Pain Med 2017;17(2):81-90❚https://doi.org/10.17245/jdapm.2017.17.2.81
Use of local anesthetics for dental treatment during
pregnancy; safety for parturient
Ji Min Lee, Teo Jeon Shin
Department of Pediatric Dentistry and Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Republic of
Korea
Pregnancy induces significant anatomical and physiological changes in the mother. Many pregnant women need
dental treatment due to poor oral hygiene related to pregnancy. However, most dentists are reluctant to provide,
and most pregnant women are reluctant to receive, dental treatment during pregnancy. Theoretically, maternally
administered drugs are transferred to the fetus. Depending on the types of drugs and the stage of pregnancy,
the effects of drugs on the mother, as well as the fetus, may vary. Local anesthetics are the most widely used
in dental treatment. It is, therefore, important to understand the potential effects of local anesthetics during
pregnancy. In this review, we will focus on the maternal and fetal effects of local anesthetics widely used in
dental treatment with consideration of the use of local anesthetics during pregnancy.
Keywords: Anesthetics, Local; Dental Care; Fetus; Pregnancy
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License
(http://creativecomm ons.org/licenses /by-nc/3.0 /) which permits unrestricted non-commercial use, distribution, and reproduction in
any medium, provided the original work is properly cited.
Received: 2017. May. 12.•Revised: 2017. May. 29.•Accepted: 2017. May. 30.
Corresponding Author: Teo Jeon Shin, Department of Pediatric Dentistry, Seoul National University School of Dentistry, 101 Daehak-ro, Jongno-gu, Seoul, Republic
of Korea
Tel: +82-2-2072-2607 Fax: +82-2-744-3599 E-mail: snmc94@snu.ac.kr
Copyrightⓒ 2017 Journal of Dental Anesthesia and Pain Medicine
INTRODUCTION
Pregnancy is a special experience in the lifetime of a
woman. The mother’s health is directly connected to that
of the fetus, and therefore, it is important for pregnant
women to maintain good health. Oral health care is
especially important for pregnant women who are soon
to be mothers both for their own health and for their
fetuses. However, many dentists and pregnant women
tend to overlook the importance of oral health care [1].
Many dentists feel reluctant to perform dental treatment
on a pregnant woman due to uncertainty about the effects
of the treatment on the mother and her fetus. Furthermore,
many pregnant women overlook the importance of
visiting dentists to receive proper oral health care during
the prenatal period [2,3]. Changes in the oral environment
and in food consumption during pregnancy can increase
the incidence of dental caries [4], while hormone changes
increase the incidence of periodontal diseases [5,6]. Poor
management of oral heath increases the incidence rates
of preeclampsia, preterm birth, and low birthweight [7].
Therefore, it is necessary that oral health be properly
managed during pregnancy and treatment be undertaken
if necessary.
Local anesthesia is administered in most dental treat-
ments, and theoretically, maternally administered drugs
can be transferred to the fetus through the placenta and
affect the fetus. Therefore, when performing a dental pro-
cedure on a pregnant woman, the effects of any drug
administered to the pregnant women must be considered
for both the mother and the fetus. In this review, we
Ji Min Lee and Teo Jeon Shin
82 J Dent Anesth Pain Med 2017 June; 17(2): 81-90
discuss a number of considerations that must be made
when trying to provide the mother with safe and effective
dental treatment using local anesthesia.
PREGNANCY-RELATED PHYSIOLOGICAL CHANGES
Pregnancy begins when a fertilized egg implants onto
the uterine wall. As gestational development proceeds,
the mother undergoes many changes in physical function.
These include various physiological alterations that are
necessary for fetal growth and development. The rate and
the extent of these changes vary with gestational age.
Understanding the normal physiological changes during
pregnancy is important when differentiating between
pregnant women with pregnancy-related complications
and healthy pregnant women.
CHANGES IN CARDIAC FUNCTIONS
Cardiovascular changes are known to begin early in
pregnancy. The largest cardiovascular change associated
with pregnancy is the dilation of peripheral blood vessels,
which reduces systemic vascular resistance [8]. The
production and secretion of various factors that induce
vascular dilation is known to increase during pregnancy.
Cardiac output also increases as a result of increased
stroke output rather than increased heart rate.
As the uterus size increases, the inferior vena cava may
be compressed by the uterus when the mother is in the
supine position; this reduces venous return and, sub-
sequently, cardiac output. Such a phenomenon is called
supine hypotensive syndrome. Therefore, it is advised for
pregnant women to lie on their side to prevent this
compression. Symptoms of cardiovascular diseases are
likely to worsen during pregnancy. For women with
preeclampsia or eclampsia, their symptoms may
drastically worsen due to changes in cardiac function
during pregnancy.
CHANGES IN ENDOCRINE FUNCTION AND METABOLISM
Pregnancy can induce diabetes [9]. When glucose
production increases in the diabetic mother, an increased
amount of glucose gets transferred to the fetus. Glucose
promotes the fetal growth, and maintains balance in the
mother’s nutritional status [10]. Gestational diabetes
commonly develops as a result of insufficient production
of insulin, which disrupts the balance in the antagonism
between insulin and estrogen and progesterone. The risk
for gestational diabetes is higher if the mother is obese,
or has a family history of type II diabetes.
Levels of triglycerides and low density lipoprotein
(LDL) and the production of high density lipoprotein
(HDL) increase during pregnancy [9]. LDL plays an
important role in the production of steroids in the
placenta. Triglycerides can be used as a source of energy
by the mother and the fetus when glucose levels are low.
A sufficient protein intake is necessary during preg-
nancy for healthy fetal development. Amino acids are
easily transferred to the fetus through the placenta, and
are used in fetal growth and development. Energy is
largely obtained from fat rather than from protein
catabolism. Thus, protein catabolism decreases during
pregnancy.
CHANGES IN RENAL SYSTEM
Due to a decrease in vascular resistance in the blood
vessels leading to the kidney during pregnancy, renal
blood flow increases, and subsequently, the glomerular
filtration rate (GFR) increases. Moreover, there are
changes in the rates of resorption and secretion of water
and metabolites in the renal tubules [11]. Upon the
activation of baroreceptors in response to reduced venous
return during pregnancy, the renin-angiotensin-aldosterone
system and the sympathetic nervous system become
activated [12]. As a result, water and sodium resorption
increases, and this induces hypervolemia and hypoosmotic
Use of local anesthetics during pregnancy
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conditions in the mother [13]. Extracellular fluid volume
and plasma volume both increase by over 30% during
pregnancy relative to before pregnancy. Blood volume
also increases by 45%.
As both the GFR and capillary permeability to albumin
increase, protein excretion and excretion of glucose and
uric acids also increases. Resorption of these molecules
by the renal tubules decreases.
CHANGES IN LIVER FUNCTION DURING PREGNANCY
The secretion of estrogen and progesterone increases
during pregnancy, and reaches the maximum rate in the
third trimester [14]. These hormones are known to affect
liver function [15]. The synthetic ability of the liver can
be assessed by measuring albumin levels and prothrombin
time (PT). While there is no significant difference in PT
during pregnancy, albumin levels decrease. Alpha-1 acid
glycoprotein levels also decrease during pregnancy. As
a result, unbound forms of administered drugs increase.
Such an increase in drug levels leads to increased
distribution of drugs within tissues and increased effects
of the drugs.
Hepatic blood flow is known to increase 1.5 fold during
pregnancy [16]. Such changes in hepatic blood flow can
affect the metabolism of drugs that are mostly meta-
bolized in the liver. Theoretically, increased hepatic blood
flow during pregnancy can decrease drug bioavailability
by increasing drug clearance.
An increase in bile acid levels during pregnancy is
known to induce sub-clinical cholestasis. Ultrasound
shows an increased fasting gallbladder volume, and an
increased residual volume after contraction. However,
these symptoms do not occur in most cases, and when
they do occur, they disappear after delivery; thus, they
do not pose serious clinical problems in most cases.
MATERNAL–FETAL DRUG TRANSFER
The mother and the fetus are connected to one another
via the placenta. Nutrients are transferred to the fetus
through the placenta, and waste products produced from
metabolic processes in the fetus are transferred to the
mother for excretion. Drugs administered to the pregnant
women may affect the fetus after they are transferred to
the fetus through the placenta. Understanding the struc-
ture and the function of the placenta is essential for
understanding how drugs are transferred from the mother
to the fetus.
PLACENTA STRUCTURE AND FUNCTION
The placenta is an important disc-shaped organ that
physically connects the mother and the fetus. The most
basic structure of the placenta is the chorionic villi. The
villi are vascular structures enclosed within the chorion
(the outermost fetal membrane). The intervillous space
is the space between villi that includes maternal and fetal
blood vessels, and has a large cavernous structure. At
Week 8 (gestational age), the blood vessels of the
mother’s uterus reach the intervillous space, which is
large enough to contain 400-500 mL of blood. Gases,
nutrients, and drugs administered to the mother are
transferred to the fetus through the placenta. Essentially,
maternally administered drugs can be transferred from the
mother to the fetus and affect the fetus.
TRANSFER OF DRUGS THROUGH THE PLACENTA
Although the method of transfer varies, most drugs
enter the systemic circulation of the fetus via passive
diffusion. Some drugs are transferred to the fetus through
various active transporters on the placenta. Drug ex-
change also occurs via facilitated diffusion, phagocyto-
sis, and pinocytosis [17].
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84 J Dent Anesth Pain Med 2017 June; 17(2): 81-90
1. Passive diffusion
Passive diffusion is most common type of drug transfer
from the mother to the fetus. Drugs are transferred
according to a concentration gradient, and no energy is
required for the transfer. The amount of drug transferred
per unit time is determined by the concentration of the
drug in the mother’s circulation and the placental
properties that affect the drug transfer. Drugs are
transferred through the syncytiotrophoblast layer, or via
water channels [18].
Passive diffusion is an important mechanism of drug
transfer for drugs that have low molecular weights, have
high lipophilicity, and are in unionized forms. Struc-
turally, the placenta consists of lipid bilayers and thus
lipophilic drugs that are not bound to proteins can freely
diffuse across the placenta [19].
Drugs that use passive diffusion are known to follow
Fick’s law of diffusion. Diffusion rates, which depend
on time, are directly proportional to the surface area of
the placenta and the concentration gradient, and inversely
proportional to the membrane thickness.
2. Facilitated diffusion
Facilitated diffusion requires carrier substances within
the placenta. Facilitated diffusion does not require energy,
similar to passive transfer. Carrier-mediated transport
systems for cephalosporin, cephalexin, and glucocorti-
coids have been reported [20, 21]. However, drug transfer
using facilitated diffusion is rare. Facilitated diffusion is
largely used for transfer of endogenous compounds to the
fetus to meet its functional metabolic demands [22].
3. Active transport
In active transport, drugs are transferred via protein
pumps in the placental membrane. This transfer mech-
anism requires energy released from adenosine triphos-
phate (ATP) hydrolysis. Energy generated by an electro-
chemical gradient resulting from the transmembrane
movement of ions may also be used. Carriers are required
for drug transfer. Carriers may become saturated, but
competitive inhibition by similar compounds does not
occur. Active transporters exist in both the mother and
the fetus. Drugs are transferred across the syncytiotro-
phoblast.
THE EFFECTS OF LOCAL ANESTHETICS ON THE FETUS
Drugs administered to the mother are transferred to the
fetus through the placenta, although the extent of transfer
varies. The effects of transferred drugs on the fetus can
vary depending on the drug type and the fetal general
conditions. Local anesthetics are the most commonly used
types of drugs in dental treatment. Pregnant women are
prone to develop dental diseases. Therefore, understand-
ing the effects of local anesthetics on the fetus is crucial
for performing safe and effective dental treatments in
pregnant women.
Moshira et al. studied toxic effects of the local
anesthetics lidocaine and etidocaine, injected into fetal
and neonatal lambs. Similar patterns of toxic effects were
observed in both groups when the concentration of local
analgesic was greater than the toxic concentration [23].
Unlike what had been expected, the toxic effects of the
local anesthetics were not more prominently expressed
in the neonatal lamb than in the adult sheep. The volume
of distribution of drugs is high in fetuses as fetuses have
a large distribution of blood vessels, and this may be why
fetuses have reduced sensitivity to toxic effects of drugs.
On the other hand, sensitivity to neurologic and cardio-
vascular toxicity of local anesthetics is increased in
fetuses with asphyxia. Binding of local anesthetics to
proteins is reduced in a fetus with asphyxia compared
to a healthy fetus, and lidocaine becomes trapped as a
result of tissue acidosis [24]. Local anesthetics must be
used with caution for fetuses at high risk of asphyxia or
with poor general conditions since they are likely to
experience side effects from local anesthetics.
The severity of the effects of a local anesthetic on a
fetus is determined by the amount of local anesthetic
delivered across the placenta. The amount of local
Use of local anesthetics during pregnancy
http://www.jdapm.org 85
Category Definition
A Controlled studies with pregnant women failed to demonstrate a risk to the fetus in the first trimester, with no evidence of risk in
later trimesters. The possibility of fetal harm is unlikely.
B Either animal reproduction studies have not demonstrated a fetal risk and no controlled studies have been conducted in pregnant
women, or animal reproduction studies have shown an adverse effect (other than a decrease in fertility) that was not confirmed
in controlled studies with women in the first trimester and have not found evidence of a risk in later trimesters.
C Either studies in animals have revealed adverse effects on the fetus (teratogenic, embryocidal, or other effects) and no controlled
studies have been conducted in women, or studies in women and animals are not available. Drugs should be given only if the
potential benefits justify the potential risk to the fetus.
D No positive evidence of human fetal risk is found, but the benefits from use in pregnant women may be acceptable despite the
risk (e.g., if the drug is needed in a life-threatening situation or for a serious disease for which safer drugs cannot be used or
are ineffective).
X Studies in animals or humans have demonstrated fetal abnormalities, or evidence of fetal risk is found based on human experience,
or both, and the risk of the use of the drug in pregnant women clearly outweighs any possible benefit. The drug is contraindicated
in women who are, or may become, pregnant.
Table 1.
Pregnant risk factor definition [29]
anesthetic delivered during local anesthesia is determined
not only by the amount of local anesthetic administered,
but also the method of administration, whether vaso-
constrictors have been used, the metabolic rate and
half-life of the local anesthetic in the mother, the extent
of fetal and maternal protein binding, and the pKa (acid
dissociation constant) of the local anesthetic [25].
Local anesthetics can be classified as two types: ester
or amide. Ester-type local anesthetics are hydrolyzed by
esterase in the plasma and have a shorter duration of
action than the amide-types. Ester-types are rapidly hy-
drolyzed in the mother’s plasma, and thus have few
effects on the fetus. Allergic reactions caused by local
anesthetics can pose a danger for both the mother and
the fetus, and ester-types are more likely to induce these
allergic reactions. In comparison, the likelihood of amide-
type local anesthetics inducing allergic reactions is very
low.
Amide-type local anesthetics, which are widely used
clinically, exert different kinds of effects depending on
their type. The amount of amide-type anesthetic delivered
to a fetus is largely affected by the extent of maternal
protein binding. Only free compounds that do not bind
proteins are transferred to the fetus through the placenta.
Therefore, the fetal-to-maternal ratio of a local anesthetic
is determined by the extent of protein binding of the local
anesthetic. Among the amide types, bupivacaine is known
to have the lowest fetal-to-maternal ratio [26]. Theoreti-
cally, bupivacaine should have the smallest effects on the
fetus among all amide types. For this reason, bupivacaine
is widely used as a local anesthetic in the field of
obstetrics. However, at toxic levels, bupivacaine inhibits
cardiac conduction, which leads to cardiac arrest with low
chances of survival. For this reason, high-concentration
bupivacaine is currently not used to induce local
anesthesia in dental treatment.
Lidocaine is the most commonly used local anesthetic
in a dental cartridge. The extent of protein binding of
lidocaine is smaller than that of bupivacaine. The pro-
portion of free lidocaine is relatively high, so the amount
of lidocaine transferred from the mother to the fetus is
also relatively high. As a result, lidocaine has a relatively
high fetal-to-maternal ratio [26]. Vasoconstrictors are
added to lidocaine to reduce the absorption of the local
anesthetic, reduce toxicity, and increase the analgesic
effects. Epinephrine is commonly added to lidocaine
contained in a dental cartridge as a vasoconstrictor.
Vasoconstriction induced by epinephrine delays the
absorption of local anesthetics by the mother, allowing
the absorption of lidocaine to gradually occur in the
maternal systemic circulation, while also allowing blood
levels of lidocaine to gradually increase. The local
anesthetic is transferred to the fetus slowly, and its margin
of safety is also increased. Considering how local
anesthetics have small direct effects on the fetus even
at submaximal doses [27], lidocaine may be considered
relatively safe for use in pregnant women. However,
epinephrine can reduce blood flow within the uterus to
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86 J Dent Anesth Pain Med 2017 June; 17(2): 81-90
Drugs Type Maximum dosage
(with vasoconstrictors) (mg/kg)
Maximum total dosage
(with vasoconstrictors) (mg) FDA category
Lidocaine Amide 7 500 B
Articaine Amide 7 -C
Mepivacaine Amide 7 550 C
Prilocaine Amide 6 400 B
Bupivacaine Amide - 90 C
Table 2.
FDA categories and maximal dose of local anesthetics
an extent that is proportional to its dose and reduce
uterine contractile force [28].
The Food and Drug Administration (FDA) has pro-
posed a classification system that classifies drugs accord-
ing to their risk [29] (Table 1). Drugs under categories
A and B are considered to pose no danger to humans.
Categories A and B differ by whether the drug has been
tested in human subjects or not. Drugs whose teratogenic
risk cannot be eliminated are classified under category
C. Category D includes drugs with positive evidence of
human fetal risk. Drugs in category X are not re-
commended for use by pregnant women.
The FDA categories and maximal dose of local
anesthetics are presented in Table 2 [26,30].
Toxic concentrations of local anesthetics are similar
between the fetus and the mother, and the toxicity of
drugs is equipotent in the fetus and the mother. When
using local anesthetics in pregnant women, the effects of
the local anesthetics on the mother and the fetus must
be considered, and the drug dose must be determined
carefully.
STAGES OF PREGNANCY
The mother and the fetus undergo different changes
as pregnancy progresses. Following the implantation of
a fertilized egg on the uterine wall, the fetus undergoes
various stages of development as gestational age
increases. Organs develop in the early pregnancy period,
and the formed organs and tissues undergo volumetric
growth in the middle and late stages of pregnancy [31].
Therefore, an identical drug may have different effects
on the fetus and the mother depending on gestational age.
Understanding the difference in the potential effects of
a maternally administered drug according to gestational
age will allow local anesthetics to be safely used in dental
treatments associated with pregnancy.
FIRST TRIMESTER
Starting from 1 month after fertilization, a closed neural
tube, a beating heart, and blood cells form. The em-
bryonic stage is the period until 10 weeks after
implantation, and the first trimester is the period until 13
weeks after implantation. During this period, the develop-
ment of the most important structures is complete, limbs
form, and the fetus starts to move. Important structures
formed during this period undergo further growth
throughout the pregnancy period, and the likelihood of
an organ deformity developing after this period is
relatively low.
A fetus may develop a birth defect when exposed to
chemicals that can induce mutations in the process of cell
growth and chromosome proliferation. Organogenesis is
actively underway during weeks 4-10 (gestational age),
so teratogenic effects may appear upon fetal exposure to
drugs during this period. Therefore, postponement of
elective dental treatment until the end of the first trimester
is generally recommended.
SECOND TRIMESTER
The second trimester is the weeks 14 through 27 in
terms of gestational age. The risk of the teratogenic
effects of drugs is lower during this period than during
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http://www.jdapm.org 87
the first trimester. Most dentists tend to be extremely
careful about performing dental treatments even during
this period [32]. However, elective dental treatment has
been reported to be relatively safe during this period.
Moreover, as the extent of physiological changes that
occur during the second trimester is not too considerable,
anesthesia is safer to perform in pregnant women for
non-obstetric surgery in the second trimester than in the
first or third trimester [33]. However, starting from week
20 (gestational age), the risk of hypotension in the supine
position increases because of aortocaval compression.
Aortocaval compression also decreases blood flow into
the uterus and may negatively affect the fetus. These risks
must be considered when performing dental treatments
in pregnant women during this pregnancy period.
THIRD TRIMESTER
In the third trimester, aortocaval compression in the
supine position is even more likely to occur because of
the enlarged uterus. By placing a cushion on one side
of the back to support the lateral position, symptoms,
including hypotension and light-headedness, that may
occur when lying in the supine position can be alleviated.
Pregnancy itself can affect neurological function [34].
Furthermore, conduction blockade occurs at a signifi-
cantly faster rate during pregnancy than when not
pregnant [35]. This demonstrates that the effects of local
anesthetics may present more prominently as gestational
age increases. Use of local anesthetics at low doses may
be possible for pregnant women in the third trimester and
may reduce the expression of the toxic effects of local
anesthetics.
CONSIDERATIONS IN DENTAL TREATMENT DURING
PREGNANCY
Research on whether surgical procedures and anes-
thesia performed on the mother in preparation for
non-obstetric treatments induce pregnancy complications
and negatively affect the fetus is important for the safety
of the fetus and the mother. Poor management of oral
health of the mother is reported to increase the incidence
of premature birth, geriatric diabetes, and preeclampsia
[36-38]; for this reason, proper oral health management
during pregnancy is an important issue. The American
Congress of Obstetricians and Gynecologists and the
American Academy of Pediatrics strongly recommend
pregnant women to undergo dental treatment [39].
However, research on whether dental treatment during
pregnancy is associated with negative pregnancy out-
comes or not is rare. In a study conducted between 1959
and 1965 that involved 60,000 pregnant women,
administration of local anesthetics such as benzocaine,
procaine, tetracaine, and lidocaine did not increase the
incidence of complications in the fetus [27]. In a study
on 351 pregnant women who required periodontal and
dental treatments, dental treatment was found not to
increase the rates of negative fetal and pregnancy
outcomes [32]. Hagai et al. recently reported no signifi-
cant difference in the rate of birth defects of the fetus
between pregnant women who were exposed to local
anesthetics for dental treatment and those who were not
exposed, although 53% of all pregnant women included
in this study were exposed to the local anesthetics during
the first trimester [40]. These results provide no clear
evidence that use of local anesthetics in pregnant women
for routine dental treatment increases complication rates
for the mother and the fetus. Therefore, dentists who are
concerned [3,41,42] and reluctant [2,43] about perform-
ing dental treatments in pregnant women should change
their perception about dental treatments in pregnant
women and believe that women can undergo all necessary
dental procedures during pregnancy.
However, special care is needed in many cases. When
the dose of a local anesthetic exceeds the maximum
permissible dose, toxic reactions may occur. Toxic effects
of local anesthetics that are associated with the central
nervous system, such as reduced consciousness and
seizure, occur first. Seizure during pregnancy is
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88 J Dent Anesth Pain Med 2017 June; 17(2): 81-90
associated with increased rates of negative pregnancy
complications. Following a seizure, catecholamine secre-
tion is increased, and subsequently, blood flow into the
placenta is reduced. Systemic seizures can lead to tissue
acidosis and hypoxia. Anticonvulsants used to treat
seizures can be transferred to the fetus through the
placenta and negatively affect the fetus. Therefore, when
performing dental treatments in pregnant women, the
doses of local anesthetics must be maintained below the
maximal permissible dose while negative aspiration is
monitored to make sure the local anesthetics are not
injected in blood vessels.
Some pregnant women may contract diseases that
increase the risk of pregnancy in the second trimester,
although most women may not. Diseases that induce
hypertension are known to develop in approximately 8%
of pregnant women. Major examples of these diseases
include preeclampsia and eclampsia. They develop
starting at week 20 (gestational age) and are accompanied
by hypertension and diabetes. The mother is diagnosed
with eclampsia if she experiences a seizure. When the
dilation of the blood vessels entering the uterus and,
subsequently, placenta perfusion are reduced, complica-
tions, including premature birth, may develop. Many
pregnant women with hypertensive diseases have poor
oral health and require dental treatment during pregnancy
[44,45]. However, theoretically, rates of complications
associated with the use of local anesthetics are high for
these women. Protein binding of local anesthetics is
reduced in pregnant women with preeclampsia or
eclampsia; therefore, a large amount of local anesthetics
can be transferred to the fetus. Moreover, epinephrine
included in a dental cartridge can significantly contract
the blood vessels inside the uterus and reduce the blood
flow to the placenta. Therefore, local anesthetics must be
used with caution in pregnant women with geriatric
hypertensive diseases.
When local anesthetics are administered to pregnant
women with fetal compromise resulting from reduced
placenta perfusion, the amounts of local anesthetics not
bound to proteins increase, tissue acidosis occurs, and the
local anesthetics may get trapped in the fetus, causing
complications. Therefore, if the general condition of the
fetus is poor because of the mother’s pregnancy-related
medical conditions, use of local anesthetics at doses that
are commonly used may still have negative effects on
the fetus. The types and doses of the local anesthetics
for dental treatments must be carefully determined for
high-risk pregnant women who are likely or are planning
to undergo dental treatment during pregnancy.
CONCLUSION
When local anesthetics are administered to pregnant
women during dental treatments, both the woman and her
fetus become exposed to the local anesthetics. Therefore,
the effects of local anesthetics on the mother and the fetus
must be considered when planning dental treatments to
improve the mother’s oral health. Fortunately, lidocaine,
which is the most commonly used local anesthetic during
dental treatments, is under category B and considered to
have almost no negative effect on the mother and the
fetus. In addition, the likelihood of the use of local
anesthetics in dental treatments for pregnant women
negatively affecting the women and their fetuses appears
to be low. Therefore, pregnant women are reluctant to
undergo and dentists reluctant to perform dental treat-
ments when the oral health of the pregnant women has
been compromised by physiological changes related to
pregnancy; thus, delaying the needed dental treatment is
not advisable. However, as exposure to drugs in the first
trimester has a high risk of teratogenic effects, dental
treatment is advised only after the second trimester as
long as it is a regular and not an emergency treatment.
In addition, pregnant women who have contracted me-
dical conditions that can induce serious pregnancy-related
complications are also more prone to experience side
effects from local anesthetics even at commonly admini-
stered doses. Thus, the dose and type of the local
anesthetic must be carefully determined for these women.
Use of local anesthetics during pregnancy
http://www.jdapm.org 89
AUTHOR ORCIDs
Teo Jeon Shin: http://orcid.org/0000-0003-4499-8813
Ji Min Lee: http://orcid.org/0000-0002-4014-520X
CONFLICT OF INTEREST: There are no financial or other
issues that might lead to conflict of interest.
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