/ Perinat Neonat Nurs
Vol. 18, No. 4, pp. 312-328
© 2004 Lippincott Williams & Wilklns, Inc.
Nausea and Vomiting
of Pregnancy
An Evidence-based Review
Mitzi Davis, PhD, RN
This article is a review of the incidence, characteristics, risk factors, proposed causes, outcomes,
treatment and nursing management of nausea and vomiting of pregnancy. Despite the fact that it
affects most pregnant women to some degree, it is poorly understood and often poorly treated.
Specific suggestions for therapeutic interventions are outlined. Keywords: nausea and vomiting
ofpregnancy, nursing care, pregnancy, stress
N
terns of nausea and vomiting of 160 pregnant
women does not mirror the classic description however.' In that sample, less than 2%
had nausea otily in the morning whereas 80%
reported nausea throughout the day. Only
50% had relief by 14 weeks, 90% had relief by
22 weeks, and 10% had nausea persisting beyond that point. In another study, symptom
diaries kept by 363 women indicated that the
mean number of days from last menstrual period to onset and end of symptoms was 39 and
84, respectively. Symptoms peaked at around
9 weeks and often ended abruptly.^
Many women w^ith nausea and vomiting
of pregnancy also complain of an increased
sense of smeU, which frequently triggers their
nausea. Food aversions and cravings are common, as is excessive salivation. Nausea and
vomiting of pregnancy are associated with
sleep disturbances that lead to increased fatigue and irritability. Neither fever nor abdominal pain, other than from retching, is prominent with nausea and vomiting of pregnancy
and, when present, may indicate other gastrointestinal, genitourinary, or central nervous
system causes that should be ruled out.
For an unfortunate few, nausea and vomitFrom the College of Nursing, The University of
ing
are more extreme and poses a significant
Tennessee, Knoxville.
threat to mother and fetus. Prior to the availCorresponding author: Mitzi Davis, PhD, RN, College of
Nursing, The University of Tennessee, 1200 Volunteer ability of modern treatment methods, hyperBlvd, Knoxville, TN37996 (e-mail: mwdavis@utk.edu). emesis gravidarum (severe nausea and vomiting) was an important contributor to maternal
Submitted for publication: July 10, 2004
Accepted for publication: September 9, 2004
mortality. Charlotte Bronte, the English author
AUSEA AND VOMITING are common
phenomena in pregnancy, experienced
by 70% to 85% of pregnant women. Despite their frequency and associated distress,
however, they are poorly understood and
often inadequately treated. This article will
discuss the characteristics, risk factors, outcomes, treatments, and nursing management
of women whose early pregnancy experience
is dominated and often diminished by nausea
and vomiting.
The terms nausea and vomiting are generally used together, but the combination may
not reflect an accurate clinical picture in pregnancy. Some women have nausea, some have
vomiting, some have both, and some are inconsistent. For some, vomiting is a result of
nausea, to be avoided if possible, and for
some, it is vs^elcome, as it brings relief. For
most, symptoms are mild and self-limiting.
"Morning sickness" is said to begin between
4 and 8 weeks after the missed menstrual period and be over for the majority of women
at 14 weeks. One description of the pat-
312
Nausea and Vomiting of Pregnancy
of Jane Eyre, became perhaps the most famous victim when she died in 1855 from severe nausea and vomiting 4 months into her
pregnancy.* While now rarely life threatening, hyperemesis gravidarum affects 0.5% to
2% of pregnancies. It is the most common
reason for hospitalization in early pregnancy
and second only to preterm labor throughout
pregnancy.''
Hyperemesis gravidarum is a diagnosis of
exclusion based on a typical presentation in
the absence of other disorders that could explain thefindings.While there is no standard
definition of hyperemesis gravidarum, persistent vomiting, dehydration, ketonuria, electrolyte disturbance, and weight loss greater
than 5% are usually considered criteria.^
When hyperemesis gravidarum is defined in
this way, it fails to address the very real misery of the woman who is severely nauseated for much of the day and cannot eat but
does not vomit, or the woman who retches
repeatedly but does not vomit. Focusing on
vomiting ignores the distress and functional
limitations of nausea. Other problems include (a) esophageal mucosal injury or tear
(a Mallory-Weiss tear) presenting as blood
in vomitus or stool and (b) transient hyperthyroxinemia manifested in 30% to 60% of
women with hyperemesis gravidarum as elevated free thyroxine and suppressed thyroidstimulating hormone. This hyperthyroxemia
is associated w^ith few or no clinical manifestations and best managed w^ith reassurance and
watchful
OUTCOME
First noticed more than 60 years ago, nausea
and vomiting of pregnancy actually portend
a good outcome, as women who experience
these symptoms have a lower rate of miscarriage than those w^ho do not.^'^ The symptoms
are thought to be due to increased human
chorionic gonadotropin (hCG) secreted by a
very robust placenta. As a teleological mechanism, vomiting served a protective function in
times before food preservation and a safe food
supply. During the time of greatest vulnerabil-
313
ity for both mother and fetus, the pregnant
woman would avoid or expel foods that might
be spoiled or contain teratogenic or abortifacient agents. Food aversions are common in
pregnancy and often include meat, coffee, alcohol, and other foods that might historically
have decreased chances for survival and perpetuation of the species.^ The pattern of selective avoidance of meats and fatty foods is
consistent w^ith the ethnographic evidence of
little or no nausea and vomiting in pregnancy
in population groups relying on grain and fruit
diets rather than on meat.'°
Huxley" proposed that nausea and vomiting of pregnancy may have another functional
role. He speculates that nausea and vomiting result in lower energy intake and consequently lower levels of anabolic hormones,
insulin, insulin growth factor 1, and maternal tissue synthesis. These changes lead to
shunting of scarce nutrients to the developing
placenta and fetus. This "embryo protection"
hypothesis seems plausible in mild cases of
nausea and vomiting and may even offer some
measure of comfort.
With only mild or moderate nausea and
vomiting, the fetus fares w^eU and there is little
apparent effect on pregnancy outcome. According to the American College of Obstetricians and Gynecologists (ACOG),'^ 7 studies
reviewed found no increase in incidence of
low birth weight among those w^ith nausea
and vomiting in the absence of hyperemesis
gravidarum and 3 studies actually found a decreased incidence of low birth w^eight. With
hyperemesis gravidarum, however, there is a
higher incidence of low birth weight. Consistent with most other studies,'*•''' a prospective study of 16,398 women •who registered
for prenatal care before 20 weeks found no
difference in the risk of congenital anomalies between those who vomited in pregnancy
and those who did not.'^ Little or nothing is
known about long-term effects.
Despite the favorable prognosis for completing the pregnancy, nausea and vomiting of
pregnancy are not without toll. In 2002, the
fiinancial burden of severe nausea and vomiting was estimated to be about $130 million.'^
314
JOURNAL OF PERINATAL AND NEONATAL NURSING/OCTOBER-DECEMBER 2004
Thisfigurewas based on costs associated with
an estimated annual average of 39,000 hospital admissions. It did not include physician
fees or the loss of productivity at home or on
the job or the cost of other patient treatment.
Gadsby et aP found time off work was needed
by 35% of working women who missed an average of 62 hours of work because of their
nausea and vomiting. Twenty-five percent of
the women in another study required time off
from work and almost 50% believed that their
work efficiency was reduced.'^
Psychosocial morbidity is common, as up
to 60% of women with hyperemesis gravidarum develop secondary depression'^ and
some elect to terminate their pregnancy.'^
In a prospective study using symptom diaries, Attard et al^" used the Short-Form 36
to measure health status and quality of life
in 223 women who had been referred to a
home health provider specializing in obstetric
home care. These women had markedly lower
scores for physical functioning, physical role,
bodily pain, vitality, social functioning, and
emotional role than did women with a normal pregnancy at 11 weeks and people with
chronic depression. Mental health scores of
the women with nausea and vomiting of pregnancy were very similar to those with chronic
depression. The authors concluded that the
changes in quality of life for those w^ith significant nausea and vomiting of pregnancy were
quite severe. Even more compelling are the
qualitative descriptions of the experience of
nausea and vomiting of pregnancy. These are
difficult to summarize and the power of the
women's ow^n words is often diluted when
presented second hand, but any provider who
cares for pregnant women is strongly urged
to read their stories^'-^^ (also M. Meighan, A.
Wood, unpublished data, 2004). In essence
these stories describe the world of the woman
with severe nausea and vomiting of pregnancy
as one of isolation, loneliness, guilt, thoughts
of pregnancy termination, frustration at being
unable to complete activities of daily living
and role function, delay in maternal role attainment, concern for the effects on the mibom child, lowered self-efficacy, and alterna-
tions in relationships with family, partners,
and friends.
ASSOCIATED OR RISK FACTORS
While no associated or risk factor(s) allows
for prediction of either presence or severity
of nausea and vomiting of pregnancy, a number are associated with its development. Perhaps because of a common vestibular mechanism, those women who have experienced
motion sickness are more likely to vomit during pregnancy (63% vs 37%).^' A history of
migraine headaches also increases the risk of
hyperemesis gravidarum. In a retrospective
record review,'^'' 37% of respondents with hyperemesis gravidarum had migraines and 27%
of women w^ith migraines had hyperemesis,
much greater than the 2% expected. The basis for the connection is not understood but
may lie in a common genetic predisposition.
The connection itself w^ould not be surprising
to those w^ith migraines who most often experience vomiting in conjunction with their
migraines. The incidence of these headaches
does tend to lessen during the course of pregnancy and that may offer some small comfort
to those afflicted with both.
One case-control study of women hospitalized with severe nausea and vomiting of pregnancy found that high daily intake of total fat
prior to the pregnancy increased the risk of
severe nausea and vomiting of pregnancy 2.9fold.^' This association was primarily due to
saturated fat intake, which increased the risk
5.4 times for each 15 g/d ingested (about the
amount in V4 lb cheeseburger). There was no
independent effect of total energy intake.
An intriguing finding is that a female fetus is most often associated with nausea and
vomiting of pregnancy. The exact ratio varies
slightly in each study, but thefindingsare consistently in favor of the female fetus and no
study was found that favored an increased ratio for male fetuses. In a registry study of 3068
•women w^ho had been diagnosed with hyperemesis gravidarum of unspecified severity, •^^
47% of women had male fetuses versus the expected population rate of 51%. One
Nausea and Vomiting of Pregnancy
found a male/female ratio of 44.3 to 55.7
among mothers admitted to the hospital for
hyperemesis gravidarum in the first trimester,
and a second study^^ found that women with
hyperemesis severe enough to warrant hospitalization had a 50% increased odds of having
a female fetus compared with controls (OR =
1.5, 95% CI = 1.4, 1.7). Women hospitaUzed
for 3 or more days had the greatest odds
of a female fetus compared to controls (1.8,
95% CI = 1.5, 2.0). Explanations for this phenomenon are speculative and vague, generally
consisting of a statement of "perhaps it is a
marker for high estrogen levels."
Nausea and vomiting of pregnancy are associated w^ith young age, first pregnancy, obesity, and stress.^^ It is said to be more common
in housewives and unemployed women,'**
but the meaning of these correlations cannot
be determined without knowing how many
women quit work because of the nausea and
the effects of multiparity on the mother's ability or decision to work outside the home.
Women are more Ukely to have nausea and
vomiting of pregnancy if their mother or sister had it and/or if they had it in a previous
pregnancy." A history of nausea when taking
estrogen-containing oral contraceptives also
increases the likelihood of nausea and vomiting of pregnancy.^^•'•^ In women seeking legal abortion, ultrasound assessments revealed
that emesis was associated with corpus luteum on the right rather than on the left, a
finding possibly due to differences in venous
drainage on the left and the right and/or ovarian vein insufficiency.'' The chance of having nausea and vomiting in pregnancy is decreased in smokers and in those who were
taking multivitamin supplements early in the
pregnancy, specifically before 6 w e e k s . ' '
CAUSE
The etiology of nausea and vomiting remains elusive. Despite intensive speculation,
there is little useful know^ledge about its
pathophysiologic features other than general
agreement that the stimulus is of placental ori-
315
gin. The agent most commonly held responsible is hCG. The argument for its involvement
is bolstered by 2 observations. One is the temporal relationship between the onset of nausea and vomiting and hCG production and the
peaks of both at around 12 to 14 weeks. Second, nausea and vomiting of pregnancy are
more pronounced in women w^ith conditions
associated with elevated hCG such as molar
pregnancy and multiple gestation. A good correlation between maternal hCG levels and the
degrees of nausea and vomiting is not always
demonstrated, however. A recent review'^ of
17 studies of hCG and nausea and vomiting of
pregnancy revealed a relationship in only 13.
The failure of some studies to sho'w a relationship may be due to varying biologic activity of
different forms of hCG.
Estrogen also is implicated in the genesis
of nausea and vomiting of pregnancy, but evidence at this point is mostly circumstantial.
Estrogens in birth control pills induce nausea and vomiting in many w^omen in a doserelated fashion.^^'^ The variation in postoperative nausea and vomiting by menstrual
cycle phase also suggests that estrogen is
involved.'^ The decrease in risk associated
with smoking may be due to lower estrogen
levels in smokers. How^ever, direct evidence
is less compelling, as a review of 17 studies of
hormones and nausea and vomiting of pregnancy found a positive relationship with estradiolinonly 5.'®
All pregnant women w^ill have increases
in hCG and estrogen, but the way in which
the individual woman responds is mediated
by genetic, gastrointestinal, vestibular, olfactory, and psychologic factors. The findings
that nausea and vomiting are more common
in women with a history of nausea and vomiting in a previous pregnancy and/or a sister
or mother who had this condition support a
genetic influence.^ There is also concordance
in the frequency of nausea and vomiting in
monozygotic twins'^ and variation between
ethnic groups.'" Some speculate that nausea
and vomiting of pregnancy might be an immunologic phenomenon, but there have been
few investigations or direct support for this
316
JOURNAL OF PERINATAL AND NEONATAL NURSING/OCTOBER-DECEMBER
idea. Its attraction seems to be the general
sense that 2 persons temporarily occupying
the same body will have some struggles.
Gastric dysfunction has been implicated in
nausea and vomiting of pregnancy. Electrogastrograms, cutaneous measures that reflect
the myoelectric activity of the stomach, show
dysrhythmias in pregnant women ^ t h nausea
and vomiting of pregnancy, but not in those
without it.^^ Such dysrhythmias have been
induced by estrogen and progesterone administration to healthy nonpregnant women
suggesting that pregnancy-induced hormonal
changes are associated with gastrointestinal
dysfunction.'^ Gastric emptying has been
thought to be slower during pregnancy but
some researchers have shown no changes in
gastric emptying rates of pregnant or nonpregnant w^omen.'"' Studies have consistently
found Heliobacterpylori infection to be more
common in women with nausea and vomiting
of pregnancy, but its significance is not weU
defined.'^''*^ For example, the presence oiH
pylori infection in 898 postpartum mothers
was determined with a 13C-Urea Breath
Test.'*' Twenty-three percent of the women
had current H pylori infections, but the
presence of this infection was not correlated
with reported symptoms of nausea, vomiting,
increased saliva production, or heartburn during pregnancy Case reports have suggested
that eradication of the infection ameliorates
symptoms and antibiotic treatment should be
considered for intractable cases.'*''
Less well explored are the vestibular and olfactory contributions to nausea and vomiting
of pregnancy. History of motion sickness is a
risk factor for nausea and vomiting of pregnancy, suggesting that a pregnancy stimulus
may lower the threshold for vestibular mediated nausea and vomiting in some w^omen.
Sensitivity to certain smells and tastes in pregnancy are well known and thought to be due
to the hyperacuity of the olfactory system induced by increasing estrogen concentrations
in early pregnancy. While once protective,
this change leads to nausea and vomiting in
susceptible women even in the absence of
noxious or toxic substances.
2004
One cannot consider the etiology of nausea
and vomiting of pregnancy without consideration of psychologic influences, and nothing will elicit a more heated response from
nauseated women than the mere hint that
"it could in be your head." The beginning
of this attribution is unclear but it received
impetus from the field of psychoanalysis.
From this perspective, nausea and vomiting
of pregnancy are considered a conversion disorder or the transformation of purely psychic challenges to physical symptoms. This
psychodynamic process is part of hysteria,
a favorite Freudian diagnosis for w^omen. It
is characterized by "emotionality, attentionseeking, seductiveness, dependency, helplessness, self-dramatization, a chameleon-like personality and sexual problems."*^ Vomiting is
seen as an attempt to expel the unwanted fetus orally. Vomiting has also been regarded
as an unconscious mechanism that symbolizes the woman's relationship with her husband or serves as a means of rejecting her
own mother. This attitude was certainly figural w^hen Dooley^^ wrote her psychoanalysis of Charlotte Bronte. Dooley wrote that
Bronte was "fearful, conflicted, and reluctant
to accept her future marriage and childbearing" and stated that "pernicious vomiting...
always has psychogenic features."
More recent studies challenge the notion
that nausea and vomiting of pregnancy are
related to conversion disorder or long-term
problems. Simpson et al''^ used the MMPI-2
and Symptom Checklist—Revised in their
comparisons of w^omen with and without
nausea and vomiting of pregnancy at 9 to
14 w^eeks and after delivery at an average of
16 months postpartum. They found evidence of disturbances in the areas of depression, anxiety, psychotism, and obsessivecompulsive characteristics in the pregnant
women with nausea and vomiting but no significant differences in the same women when
tested after their delivery. One explanation is
that the presence of psychologic symptoms
in women in the throes of nausea and vomiting episodes is more likely the result, not the
cause, of their physical maladies. As
^^
Nausea and Vomiting of Pregnancy
proposes, nausea and vomiting of pregnancy
"could subject any normal expectant mother
to stress sufficient to trigger adjustment disorders, generalized anxiety or even depressive
episodes." A recent report in the nursing literature confirms the frequent coexistence of
depression and nausea and vomiting of pregnancy, but the researchers were unable to say
if the depression preceded or resulted from
the nausea and vomiting.'*^ Another study"*^
rejected the idea that nausea and vomiting of
pregnancy are a conversion disorder, but suggested that psychologic responses to the physiologic stimuli could become entrenched or
conditioned with the 2 interacting to exacerbate the condition. As such, psychologic interventions aimed at dealing with symptoms
might be helpful.
Despite the lack of data supporting a psychogenic origin for nausea and vomiting of
pregnancy, 21st-century medical texts still
give it prominence. One states, "there are
two leading theories: hormonal and psychological" and after, one sentence about hormonal theories, says "psychological studies
suggest that women with nausea and vomiting of pregnancy are more likely to have
had an undesired pregnancy and have negative relationships with their mother." Another says, "treatment of nausea and vomiting
of pregnancy consists primarily of reassurance ... along with in-office supportive psychotherapy." The ACOG practice bulletin
concludes its section on psychologic theories
with the statement that "it is likely that the
concept that nausea and vomiting of pregnancy reflect a psychologic disorder has impeded progress toward a greater understanding of the true etiology of the condition."'^
Stress has been explored as a possible cause
and it is well known that reactions to stress
can be somatic and include vomiting. Iatrakis
et aP" found nausea and vomiting of pregnancy were associated with stress, lack of
information about pregnancy, childbirth and
health of the fetus, and poor communication
with the husband and the physician. These
conclusions were based on an undescribed
"specially constructed questionnaire" admin-
317
istered to 102 women. On the other hand,
studies have found no differences in martial status, whether the infant w^as planned,
or positive feelings about the pregnancy between w^omen with nausea and vomiting of
pregnancy and those without.'^'^^ The growing consensus is that stress is more likely the
result, not the cause, of nausea and vomiting. After fmding that women with nausea
and vomiting of pregnancy are more hypnotizable, researchers^^ suggested that some
women may be more susceptible to environmental cues that trigger emesis. This susceptibility may lead to the development of vomiting as a conditioned response to specific
environmental cues, much like chemotherapy patients who develop anticipatory vomiting. In this situation, psychologic interventions could again be helpful.
MANAGEMENT
Management of nausea and vomiting of
pregnancy depends on the severity of symptoms and can range from dietary changes
to hospitalization and total parental nutrition. It is preferable to start with dietary and
lifestyle changes, w^hich will be considered
under nursing considerations, and then move
to medications if necessary. It is important to
intervene early, however, as "failure to treat
early manifestations of nausea and vomiting of
pregnancy increases the likelihood of hospital
admissions for hyperemesis gravidarum. "^^ It
also no doubt improves the quality of life for
this woman and her family.
Adequate treatment is hampered by a number of things. Nausea and vomiting of pregnancy are a self-limiting disorder for most
women, so treatment is often delayed. Second, because the pathophysiology of nausea
and vomiting of pregnancy is poorly understood, the treatment approaches are aimed
at symptom management. Ethically, drugs for
use in pregnancy cannot be tested in classic
experimental fashion and treatment modalities are often empirical and poorly defined.
Indeed, Herxheimer's review of reports since
1950 ended with the conclusion that no
318
JOURNAL OF PERINATAL AND NEONATAL NURSING/OCTOBER-DECEMBER 2004
treatment modality for nausea and vomiting
of pregnancy has ever been adequately tested
in a prospective, double-blind, comparative
study.'* Finally, women, families, and caregivers tend to overestimate the teratogenic
risk of medications for nausea and vomiting of pregnancy and underutilize pharmacologic therapy.''^ Women suffering from nausea and vomiting of pregnancy often do not
receive therapy because of fears of adverse
effects of medications during the critical embryonic period. In the wake of the thalidomide tragedy of the 1960s and the increasingly litigious climate, limiting pharmacologic
treatments is understandable, but its judicious
use is often medically necessary and/or simply
humane.
MEDICAL/PHARMACOLOGIC
TREATMENT
To understand pharmacologic treatments
for nausea and vomiting, some understanding
of the physiology underlying them is useful.
The vomiting center located in the medulla
initiates the vomiting reflex. Signals from
the cerebral cortex (fear, memory, anticipation), from the sensory organs (smells, pain),
and from the inner ear (motion), are mediated by histamine, acetylcholine, dopamine,
and serotonin. Interference with these mediators prevents activation of the vomiting
center and they are the targets of most therapeutic interventions.'^ Pharmacologic therapy should begin with those agents with the
best safety profile.
The recently released practice guide of the
ACOG'^ says there is consistent scientific information on which to base a recommendation for taking 10-mg vitamin B^ (pyridoxine)
or 10-mg vitamin B^ plus V2 of a scored 25-mg
doxylamine tablet orally every 8 hours. This
formulation w^as Bendectin, w^hich was taken
off the market in the United States in 1983
for unfounded accusations and nonmeritorious lawsuits alleging congenital malformations. More than 30 million women had taken
Bendectin before its voluntary withdraw^al,
and it has continued to be available in Canada
as Dilectin. The focus of at least 25 epidemiological studies and 2 meta-analyses, it is the
world's most studied drug in pregnancy.'^
The Food and Drug Administration (FDA) has
laid the groundwork for Bendectin's reintroduction to the US market, and it may be available again in the near future. In the meantime,
w^omen can make their own by combining
10-mg vitamin B6 and doxylamine, marketed
over the counter as Unisom Tabs with 25-mg
doxylamine. One half the Unisom tablet will
provide 12.5-mg doxylamine, which approximates the dose in the original formulation.
The most effective regime of Bendectin included 2 tablets at night so 1 full Unisom Sleep
tablet can be taken at night and V2 tablet
in the morning and another in the afternoon
along with the appropriate amounts of vitamin B6. The instructions to the patient must
be very clear, however, as she is to get Unisom Sleep Tabs not Gels. Instead of the 25-mg
doxylamine found in the Tabs, Unisom Sleep
Gels contain no doxylamine but diphenhydramine (Dramamine) instead. Advise the
woman ahead of time that there is a w^arning on the label, which says it should not be
taken, if pregnant, without consultation with
a provider, but it is okay for her to take it. Compounding pharmacies may also make up the
combination on request and it is available on
the Internet.
Other drugs prescribed include antihistamines or HI receptor antagonists (diphenhydramine/Benadryl or dimenhydrinate/
Dramimine), dopamine receptor blocking
drugs (metroclopramide/Reglan), and serotonin agonists (ondansetron/Zofran). Data for
most of these are limited but reassuring.'^'^^
Side effects are not uncommon but are usually
mUd. Corticosteroids may be used as a last
resort in severe cases but a meta-analysis of
epidemiological studies revealed a marginally
increased risk for major malformations and
particularly for oral clefts.^'""^^
The vitamin B6 or pyridoxine referred to
earlier can be used in combination with doxylamine as described or alone. It is the best
tested vitamin-based therapy for nausea and
vomiting of pregnancy. Controlled trials using
Nausea and Vomiting of Pregnancy
30- to 75-mg pyridoxine per day for 5 days
have shown its efficacy.^^ Women taking vitamin B6 had significant decreases in nausea
and a trend toward reduction in episodes
of vomiting when compared to those taking
placebos. Vitamin B6 has also been associated with a lower risk of congenital heart
defects.'^ The mechanism of action of vitamin B6 on nausea and vomiting of pregnancy
is not known. It is not clear that blood levels of vitamin B6 are related to nausea and
vomiting of pregnancy and at least one study
found no relationship between usual indicators of vitamin B6 status and nausea and vomiting of pregnancy.'^ There is no evidence
of toxicity at the doses tested, but there is
concern as large doses of pyridoxine have
been shown to cause reversible peripheral
neuropathy (weakness, numbness, or tingling
of fingers and toes) in nonpregnant adults and
no one can be sure of safe limits for the developing embryo.
The upper tolerable level of vitamin B6 in
adults is 100 mg/d and prenatal vitamins generally contain 5 to 45 mg, so most women
should continue to take a daily prenatal vitamin but will need a separate vitamin B6 supplement, which is available in health food
stores, groceries, conventional pharmacies,
and on the Internet, etc. Megadoses are neither necessary nor recommended so she
should find a formula that will allow her to
take amounts shown to be effective and safe.
Most vitamin B6 supplements contain much
more than needed. Although they are difficult
to find, 25-mg formulations exist and with a
pill cutter the w^omen will be able to approximate 10 mg recommended by the ACOG. In
recent years, in the absence of Bendectin, may
providers have recommended 50 mg of vitamin B6 with the doxylamine with no apparent
ill effects. Some women will be happy with
this dosage and others will want the more
conservative amount officially recommended.
Any buyer of vitamins may be reassured by the
presence of a US Pharmacopoeia label indicating that the product has the ingredient(s) it
says, at the declared dosage, wiU disintegrate
or dissolve effectively, has been screened for
319
harmful contaminants, and has been manufactured using safe, sanitary, and well-controlled
procedures.^^
According to the Practice Guidelines of the
ACOG, there is one nonpharmacologic intervention recommended, although the scientific evidence is limited or inconsistent.'^
That is ginger, 250 mg 4 times daily. Ginger
iZingiber officinale} has a long history in
food preparation and as an herbal medicine.
It is mentioned frequently in lay literature and
because it is "natural" it may be more acceptable to some people who relate "natural" to
"good." Its protective effects are considered
local in the gastrointestinal tract and are probably related to its stimulation of motility.^"
Ginger is thought to improve intestinal muscle tone and stimulate the flow of saliva, bile,
and gastric secretions. One constituent of ginger (a diterpenoid) has been shown to have
activity similar to 5-HT3 antagonist (Zofran)
and other emetic drugs. Ginger root extracts
containing gingerols have been found to inhibit the growth of certain strains of H pylori in vitro and this activity may contribute
to its efficacy in nausea and vomiting of
pregnancy.^'
The scientific demonstration of the efficacy
of ginger has been shown in controlled trials using 250 mg 4 times daily for nausea
and vomiting of pregnancy. In the first trial,
a crossover design, there was a significant
reduction in vomiting episodes and 70% of
women reported less nausea during the ginger phase.^^ In a more recent experimental trial,^' w^omen were given 1 g daily or a
placebo for 4 days. They reported significantly
fewer episodes of vomiting and significantly
greater improvement in nausea scores w^hen
taking the ginger. Twenty-eight of 32 in the
ginger group had improvement in nausea (by
visual analog scale) compared to 10 of 35 in
the placebo group (P < .01). Portnoi et al also
demonstrated efficacy in a prospective comparative study that looked at both the safety
and the effectiveness of ginger in the treatment of nausea and vomiting of pregnancy.^^
The outcomes of 187 women who had taken
ginger in any form in the first trimester were
320
JOURNAL OF PERINATAL AND NEONATAL NURSING/OCTOBER-DECEMBER 2004
compared with those of 187 women who
had not taken ginger but had taken other
nonemetic drugs. They were matched for alcohol, smoking, and age. The amount of ginger was not documented but was reportedly
consumed as capsules, tea, cookies, candy,
inhaled ginger pow^der, crystals, and sugared
ginger. Almost half the women who completed the survey did not find the ginger effective but even including them, there was a
decrease in mean nausea scores when on ginger. The investigators concluded that ginger
was somewhat helpful in treatment of nausea
and vomiting of pregnancy and that capsules
were the most effective delivery mechanism.
This study also looked at safety of ginger in
the first trimester. It had 80% power to detect a 3.5-fold increase in the rate of malformations and found no statistically significant
differences in incidence of major malformation, rate of abortions, live births, stillbirths,
gestational age at birth, or birth weight.
The evidence, both scientific and traditional, is that ginger is safe and effective for
some women with mild or moderate nausea
and vomiting of pregnancy. Although side effects are minimal, there have been some reports of heartburn and dermatitis. One investigator warned that ginger root contains
thromboxane synthetase inhibitor that could
inhibit thromboxane formation and platelet
aggregation.^"* Although this has never been
demonstrated, the concomitant use of ginger and anticoagulants is not recommended.
It is hoped that pregnant women have already been advised not to be taking aspirin
during their pregnancy. There have been no
published reports of fetal anomalies associated with the use of ginger. It is on the
FDA's "generally recognized as safe" Ust, and
the treatment dosages are similar to dietary
dosages.
Deciding to take ginger is only the first
step. Finding the right formulation can be a
challenge for those not experienced with
complementary and alternative medicine.
The Internet would seem like a good place
to begin, but a Google search for "ginger capsules" did not immediately identify the 250-mg
dose form. Many products contained unspecified amounts of ginger, saying only things
like "ginger capsules, each bottle contains 60,
$19.90." Mixed in with 1000 mg, 550 mg,
500 mg, tea, ginger root, cayenne ginger with
the bottles labeled marshmallow root, herbal
formula ginger root, herbal single ginger root,
stomach comfort ginger capsules, and ginger
root extract vegicaps, Drugstore.com did have
a product labeled 250-mg ginger capsules for a
little over $10.00 for 60 capsules, presumably
what a pregnant woman would safely take.
Since ginger is a spice used in many cultures over thousands of years without reports
of anomalies, it would appear safe but many
women are understandably cautious and want
to follow professional recommendations. The
ginger capsules are easier on the stomach and
contain the dried form of ginger, w^hich is
more potent than fresh root, so less is needed.
The two are not interchangeable. Ginger ale
is a traditional treatment for nausea but many
have ginger flavorings only and will not be
effective.
Cannabinoids (marijuana) have been effective in reducing chemotherapy-induced nausea and vomiting and undoubtedly have been
self-prescribed for nausea and vomiting of
pregnancy. Not surprisingly in the United
States, no studies that examined either the efficacy or the safety of this intervention were
located. Retrospectively, marijuana exposure
has been linked to decreased growth parameters at birth.^^ Inquiries about use of marijuana as well as other drugs should always be
made and the w^oman treated in such a manner that she is most likely to be truthful with
the providers.
NONPHARMACOLOGIC TREATMENT
Acupuncture has been systemically tested
in a limited number of trials. A single-blind,
randomized, controlled trial in w^hich 593
women less than 14 weeks with nausea and
vomiting were treated weekly for 4 weeks
found no difference in vomiting but less nausea and dry retching in treatment women
Nausea and Vomiting of Pregnancy
versus controls.^*' No doubt many women
improved during the study regardless of treatment group because of advances in gestational age. Acupuncture requires trained practitioners and may be no better than cheaper
and more readily available acupressure, so its
use may be limited. For those who want to
try, a list of certified acupuncturists can be
found at www.medicalacupuncture.org, the
Web site of the American Academy of Medical
Acupuncture, or WAVw.acupuncturealliance.
org, the Web site of the National Acupuncture
and Oriental Medicine Alliance.
Of interest to more women is acupressure,
stimulation of P6 Neiguan point either manually or with elasticized bands. According to
the principle of chi (the energy present in the
organism), application of pressure to specific
points on the body blocks abnormal flow
and relieves signs and symptoms related to
that pressure point. For nausea and vomiting,
pressure is applied to the P6 point on the inside of the wrist, about 2 to 3 fingerbreadths
proximal to the wrist crease, between
the tendons, about 1 cm deep. Manually
the woman or someone else applies pressure
for 5 minutes every 4 hours. Alternately, pressure can be applied by wearing an elasticized
band with a 1-cm round plastic protruding
button that is centered over the acupuncture
point. These are described as "efficacious for
many patients" by Roscoe and Matteson,^^
who reviewed published literature examining
their efficacy for relief of nausea. The ACOG
says evidence supporting or refuting acupressure in nausea and vomiting of pregnancy is
"equivocal."'^ They are widely available at
most drug stores and over the Internet (as
Sea Bands) for less than $10.00.
The FDA has recently approved a wristbandtype, miniaturized, battery-operated transcutaneous electrical nerve stimulator designed to stimulate the P6 acupuncture site.
Called the Reliefband, it has been found to
be helpful for mild to moderate nausea and
vomiting but not for severe symptoms.^^ It is
available over the Internet for less than $100,
and clients with nausea and vomiting of pregnancy may want to pursue this option.
321
NURSING CONSIDERATIONS
Nursing interventions should begin with
prevention. Several reports suggest that vitamin supplementation very early in pregnancy
(prior to 6 weeks gestation) is associated with
a decreased incidence of nausea and vomiting of pregnancy.'^'^^ Encourage all sexually
active women of childbearing age (or ideally
aU w^omen of this age) to take a multivitamin prior to known pregnancy for prevention of nausea and vomiting of pregnancy as
well as neural tube and other birth defects.
This instruction can easily be a part of the
care of any woman whether she is seeking
scheduled, episodic, or prenatal care. In addition, collaboration with organizations such as
March of Dimes, which recently had a major
campaign to increase foUc acid intake through
multivitamins taken before pregnancy, can be
initiated.
Assessment for the presence and severity
of nausea and vomiting of pregnancy is part
of the nurse's role. That may seem simple—
that all one would do is ask—but use of
a standardized assessment tool w^ill allow
more accurate surveillance and communication between team members. Koren et aP recently published a modification of the standard Rhodes scoring system, which yields
similar results but is easier to use. Called
the PUQE (pregnancy-unique quantification
of emesis and nausea), it consists of 3 questions. These are as follows: in the last 12 hours
for how long have you felt nauseated or sick to
your stomach (1 = not at all to 5 = more than
6 hours); in the last 12 hours how many times
have you vomited or throw^n up (1 = none to
5 = 7 or more times); in the last 12 hours
how many time have you had retching or
dry heaves without bringing anything up
(1 — none to 5 = 7 or more times)? A total
score of fewer than or equal to 6 is considered
mild nausea and vomiting, 7 to 12 moderate,
and more than or equal to 13 severe. This scoring system is more comprehensive than an assessment of vomiting alone and more accurately reflects the associated morbidity from
nausea and/or retching without vomiting. It
322
JOURNAL OF PERINATAL AND NEONATAL NURSING/OCTOBER-DECEMBER
may also allow for different and more targeted
interventions than those focused on vomiting
alone.
Assessment of weight is part of regular prenatal care, and not surprisingly there is a
significant relationship between the maximal
number of daily vomiting episodes and weight
loss. There is wide variation, however, and
some women may be very ill with little w^eight
loss.*' The best assessment of the degree of illness is the woman's own.
Dietary advice is generally the first step in
helping a woman with nausea and vomiting
of pregnancy. There are no clinical trials supporting the efficacy of dietary recommendations and generally these recommendations
are the result of trial and error of countless
numbers of women. Most, however,findthem
at least somewhat useful.^° The typical instruction is to eat saltine crackers before arising. Potato chips are tolerated well by many
women and others find melba toast, plain
popcorn, or dry cereal more appealing substitutes. This may be helpful to some, but the efficacy of carbohydrate intake in general is not
supported by the limited research available.
Protein predominant meals have been show^n
to alleviate nausea and vomiting in pregnant
women, w^hereas calorically equivalent carbohydrate or fat predominant meals show^ed
no statistically significant effects.^' The reduction in nausea corresponds w^ith changes
in gastric rhythms and proceeds in a timedependent fashion with maximal decreases
at 45 minutes after eating. This research supports the common advice to eat small, highprotein meals but does not support the prevalent recommendation for carbohydrates in the
morning. The best advice for an individual
woman is to do •what makes her feel better,
but trying a protein snack 45 minutes before
getting out of bed is one option she should
test.
There are other standard dietary instructions and suggested lifestyle changes for
women •with mild to moderate nausea and
vomiting of pregnancy (Tables 1 and 2). Behavioral interventions such as slow deep breathing, the same breathing techniques taught for
2004
Table 1. Dietary instructions
• Try dry, bland food such as the BRAT diet
(bananas, rice, apples, and toast)
• Avoid fat or spicy foods (fat stays in the
stomach longer)
• Eat high-protein snacks
• Snack before going to bed
• Don't force self to eat and don't let others
force you—it
• Eat lots of little meals; don't let the
stomach get empty
• Drink liquids in a cup with a Ud on if the
smell is a trigger
• Ginger ale may help but the ginger
content varies widely between brands
• Try foods that may not appeal but don't
disgust you
• Lemon in tea or water or just licking
lemon slices may help
• Try peppermint gum
• Take advantage of good days or good
hours of the day. Eat what you can when
you feel like it
• Cold foods have less odor and may be
easier to swallow
early labor, will be effective in many women.
Use of positive imagery is also advocated.
While its effectiveness in nausea and vomiting of pregnancy has not been systematically
shown, it does work in motion sickness.^'' The
nurse can also help with identification of triggers and ways these might be avoided. Triggers include sight, smell, and thought of food
(TV, others eating); noise (TV, other children);
motion; standing or sitting upright; empty
stomach; odors (scented cosmetics, chemicals); sleeping with partner (intolerance to
smells and motion); pressure on abdomen
(too tight clothes, children or pets on lap),
stimulation of gag reflex (taking pills), riding
in the car; reading; and talking.
Drug therapy is recommended only if dietary and Ufestyle measures fail to bring adequate relief. Some women doubt the safety
of drugs during pregnancy and regard alternative therapies as less toxic. They may prefer
Nausea and Vomiting of Pregnancy
323
Table 2. Lifestyle change
• Avoid loud, crowded places and too much activity
• Avoid warm places and those with limited air flow
• Avoid places and activities where smells are prominent, such as buses, subways, around
smokers, around people changing diapers; use the exhaust fan in the kitchen or use the oven or
microwave more than the range
• Take vitamins at night and see if they can be tolerated better than in the morning. Children's
vitamins, such as Flinstones,^^ are chewable and may be better tolerated. You may be able to
take a folic acid supplement that is smaller
• Brush teeth after meals instead of upon arising. Try fruit-flavored toothpaste
• Get out of bed slowly (effectiveness may be due to similarity to motion sickness)
• lie down when nauseated. In one study, 63% of respondents identified lying down and
remaining still as the best method for dealing with their nausea and vomiting*^
• Be a'ware of the effects of exercise since increased minutes of exercise have been correlated
^vith increased nausea and vomiting*'
• Avoid stress. Living with the constant or frequent threat of nausea and/or vomiting and/or
retching is a stressor in itself
natural remedies to synthetic remedies, and
pregnant women appear to mirror the trend
in the general population of increasing use of
complementary and alternative medicine.^' It
is therefore critical for the ntirse to be able to
opetily discuss alternative remedies. The most
cotnmonly cited herbs for nausea and vomiting of pregnancy are ginger, chamomile, peppermint, and raspberry leaf. Of these, only
ginger has been well studied. There is particular concern about raspberry leaf as it is
thought to increase the risk of uterine contractions and preterm labor, and it is not recommended generally during pregnancy.
Early intervention is thought to decrease
the severity and duration as well as prevent
complications of nausea and vomiting. The
above suggestions, along with acknowledgment of her discomfort, will bring relief to
many women, but not to all. Be prepared
to help the women with severe nausea and
vomiting.
First of all, to increase safety, the woman
with hyperemesis gravidarum should be given
clear instructions about when to call her
provider. The specifics of these vary somew^hat but generally include calling if her urine
is very dark or she does not urinate for more
than 8 hours; if she has abdominal pain, fever,
severe weakness, or faintness; if she votnits
blood or her throat is extremely sore (indications of a Mallory-Weiss tear); if she cannot keep anything down for 24 hours; or if
she votnits repeatedly and catinot stop. She
should be told to watch for signs of dehydration, which include concentrated and/or infrequent urination, dry lips and mucus membranes, and lightheadedness. She can buy
Ketostix from the drugstore to motiitor her
urine for the presence of significant ketones,
the by-products of fat breakdown indicating
an inadequate caloric intake, which should be
reported to her provider.
Many women with nausea and votniting of
pregnancy become sick and vomit when trying to take glucola for their routine glucose
screen for gestational diabetes. Jelly beans
have been tested as a possible alternative to
the glucola in 2 studies.^^'^ The investigators
found no significant differences between
1-hour glucose values, frequency of discrepant results, sensitivity, specificity, or predictive value among those taking the standard 50-g glucose drink and those taking jelly
beans. There were no side effects of the jelly
beans and they were preferred by 76% of
the women. The only jelly beans tested were
18 Brach, 150/lb, and 28 Brach, 110/lb, so
restilts using other brands are not known.
The pregnant woman can ask her provider
324
JOURNAL OF PERINATAL AND NEONATAL NURSING/OCTOBER-DECEMBER
about this option especially if she meets the
criteria for low risk as defined by Barbour
and Friedman.^' These criteria include weight
normal before pregnancy, no known diabetes
infirstdegree relatives, no history of poor obstetric outcome or macrosomic infant, member of an ethnic group with a low prevalence
of gestational diabetes mellitus, no history
of abnormal glucose tolerance, and age less
than 25.
Counseling regarding pharmacotherapy is
indicated in most cases. Evidence-based education about the risks to the fetus of various treatment modalities can decrease the unfounded fears of many women.^^ Drugs will
in all likelihood never be tested in standard
ways in pregnant women. Because of this, use
of the FDA classification system (A, B, C, D,
X) by patients or providers may lead to unnecessary maternal anxiety. Very few drugs
are known teratogens, but many drugs are
classified as category X because they have
not been tested in pregnant women. This
and other issues lead the Teratology Society
to suggest replacing the FDA classifications
with narrative statements that summarize and
interpret available information.^ The nurse
mightfindspecific descriptions and data from
teratogen databases to be more helpful in
putting risks of drugs into context. Women
can be especially reassured by the extensive
use and safely record of doxylamine and vitamin B6, components of Bendectin, and of
ginger.
Women who are still unable to keep liquids down or become ketotic and dehydrated
will probably require bospitalization and intravenous fluids. In the not so distant past,
women hospitalized with nausea and vomiting of pregnancy were given w^hat can euphemistically be called sensory deprivation
therapy. They were put in a private room
with no TV, radio, outside telephone calls, visits from family, etc. This approach seemed
to punish the victim and lead to secondary
depression, but many women did get better
in this environment. Because lights, noise,
smells, activity, etc, are triggers for nausea
and vomiting in many women, they should
be asked what limits they would like imposed
2004
during their hospital stay and supported in
that decision.
Online support groups such as wv^^w.
hyperemesis.org
and
http://www.
hyperemesisgravidarum.org/ and chat rooms
may be helpful sources of support and information, but the mother should be warned
not to believe or try everything she reads.
Some information not only can be useless but
Table 3. Stressors in women with nausea and
vomiting of pregnancy
• Lack of understanding and support from
others
• Inability to take vitamins or eat healthy
• Taking medications perceived as risky
• Missing out on the "fun" of being
pregnant
• Loss of a "normal" pregnancy
• Lost work days or quitting work
• Putting life "on hold"
• Longing to eat and drink normally
• Money expended on care and support
Lack of energy, fatigue
Irritability and lack of enjoyment of life
Memory loss or inability to think clearly
Burden of care and time on others
• Lack of socialization, isolation
• Inability to prepare for birth and arrival of
baby
• Inability to care for family and home
• Fear of painful treatments
• Wanting pregnancy over or to end the
misery
• Others' perception that hyperemesis is
only in her mind
• Reluctance of doctors to treat because of
cost or liability
• Weight loss or inadequate weight gain for
gestational age of baby
• Fluctuating emotions due to hormones
and illness
• Sense of inadequacy and failure at being
unable to cope or function
• Fear of pain or difficult birth
• Fear of morbidity or death
• Difficulty bonding ^ t h infant
• Lack of energy and socialization with
other children
• Lack of excitement about infant's arrival
(from www.hyperemesis.org)
Nausea and Vomiting of Pregnancy
may be harmful and should be discussed with
her nurse practitioner, midwife, or physician.
Providers, receptionists, phlebotomists, etc,
should convey a truly convincing and heartfelt message that the women with nausea and
vomiting of pregnancy are welcome to call if
she has any questions.
Partners and/or other family members need
advising too. They are perceived by many
women as offering little support.'^ O'Brien
and Naber^^ suggest that caregivers validate the need for pregnant women to make
changes in lifestyle that will enable them to
achieve comfort. Mazzotta et al^° found that
adverse effects of nausea and vomiting of
pregnancy on both her partner's daily life and
her relationship w^ith her partner were significantly associated with a woman's consideration of termination of pregnancy. Other
narrative reports support the isolation felt by
many women and the difficulties they have
in fulfilling roles of partner and mother when
they are suffering from nausea and vomiting
of pregnancy^''^^ (also M. Meighan, A. Wood,
unpublished data).
Conventional psychotherapy is not usually
warranted but may be useful in dealing with
325
associated depression and negative feelings. A
review of the stressors identified by women
with this disease reinforces the challenges imposed by the presence of severe nausea and
vomiting at a time that should be filled with
anticipation and assumption of the mothering role. Many of these stressors have been
alluded to earlier but seen in their entirety, illustrate why these women are so in need of
nursing care (see Table 3).
Nausea and vomiting of pregnancy have
plagued pregnant women, their families, and,
to some extent, their fetuses for untold years.
Its cause is still speculative and its treatment poorly refined. Suspicion that symptoms
are psychogenic in origin has diminished the
quality of care women have received. Nurses
play a critical role in the prevention, management, and successful adaptation to symptoms of this common, but distressing, disorder. More nursing research is needed, but
in the meantime more consistent application
of existing knowledge can help women with
nausea and vomiting of pregnancy maximize
the physiologic, psychologic, and emotional
aspects of one of the most important times of
their lives.
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