Clinical management and progress in sudden sensorineural hearing loss during pregnancy

Abstract

Sudden sensorineural hearing loss (SSNHL) is a relatively rare, but distressing, disease in pregnant women. Little is known about the causes, clinical manifestations, treatments, and prognosis of SSNHL. Some hypotheses have been proposed to explain the pathophysiological mechanism of SSNHL, but most of them have not been identified. This article reviews the existing literature to present a summary of this clinical problem. Most patients suffer from SSNHL in the second or third trimester, and show moderate to profound hearing loss. The interval between the initial treatment and onset of hearing loss is less than 10 days in most patients. Some patients with SSNHL show tinnitus, vertigo, or dizziness, and fullness of the ear. Although some patients have a tendency for self-cure, treatment with intravenous dextran 40 combined with intratympanic corticosteroids is probably a safe and effective therapeutic strategy for pregnant patients with SSNHL. Further clinical research is necessary to identify the best therapeutic strategy for these patients.

Full text

Special Issue: Rare Diseases: Advances in Diagnosis,
Prevention, Treatment and Management
Clinical management
and progress in sudden
sensorineural hearing
loss during pregnancy
Shaobing Xie
1,2
and Xuewen Wu
1,2,3
Abstract
Sudden sensorineural hearing loss (SSNHL) is a relatively rare, but distressing, disease in pregnant
women. Little is known about the causes, clinical manifestations, treatments, and prognosis of
SSNHL. Some hypotheses have been proposed to explain the pathophysiological mechanism of
SSNHL, but most of them have not been identified. This article reviews the existing literature
to present a summary of this clinical problem. Most patients suffer from SSNHL in the second or
third trimester, and show moderate to profound hearing loss. The interval between the initial
treatment and onset of hearing loss is less than 10days in most patients. Some patients with SSNHL
show tinnitus, vertigo, or dizziness, and fullness of the ear. Although some patients have a tendency
for self-cure, treatment with intravenous dextran 40 combined with intratympanic corticosteroids
is probably a safe and effective therapeutic strategy for pregnant patients with SSNHL. Further
clinical research is necessary to identify the best therapeutic strategy for these patients.
Keywords
Sudden sensorineural hearing loss, pregnancy, dextran, intratympanic steroid, tinnitus, vertigo,
acoustic neuroma
Date received: 20 June 2019; accepted: 29 July 2019
Introduction
Sudden sensorineural hearing loss
(SSNHL) is an emergency medical condi-
tion, which is defined as hearing loss of at
least 30 dB in three contiguous frequencies
within 3 days. As a symptom of acute
impairment of the inner ear, the etiology
1
Department of Otolaryngology Head and Neck Surgery,
Xiangya Hospital of Central South University, Changsha,
Hunan, PR China
2
Key Laboratory of Otolaryngology Major Diseases
Research of Hunan Province, Changsha, Hunan, PR China
3
National Clinical Research Center for Geriatric
Disorders, Xiangya Hospital of Central South University,
Changsha, Hunan, PR China
Corresponding author:
Xuewen Wu, Department of Otolaryngology Head and
Neck Surgery, Xiangya Hospital of Central South
University, 87 Xiangya Road, Changsha, Hunan 410008,
China.
Email: xwwu840903@hotmail.com
Journal of International Medical Research
48(2) 1–12
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of SSNHL has been proposed by some
hypotheses, but most of these etiologies
have not been identified. With an increase
in the incidence of SSNHL, it is no longer
considered as a rare disease. An American
survey estimated the annual incidence of
SSNHL at 27 per 100,000 people,
1
and a
study in Germany showed a prevalence as
high as 160 cases per 100,000 per year.
2
However, this clinical disorder may occur
at a low incidence rate in pregnant
women. A population-based study from
Taiwan showed an incidence of SSNHL at
2.71 per 100,000 pregnant women.
3
A series of obvious physiological
changes occur during pregnancy, which
lead to considerable challenges on the hor-
monal system, cardiovascular system,
hematological system, and others.
4,5
Although these changes are proposed to
cause occurrence and development of
SSNHL in pregnant women, all of them
have not been confirmed.
6
A retrospective
study in Taiwan showed that SSNHL was
attributed to 21% of inner ear disorders in
pregnant women.
7
There have been few
reports involving SSNHL in pregnant
women because of its rare occurrence.
Therefore, little is known of the causes, clin-
ical manifestations, treatments, and prog-
nosis of SSNHL. This review focuses on
the possible etiologies, clinical manifesta-
tions, treatments and prognosis of SSNHL
in pregnant women to present a summary
of this clinical problem.
Literature search
We searched the China National Knowledge
Infrastructure (CNKI), Wanfang Database,
VIP Database, Chinese Biomedical
Literature (CMB), PubMed, Embase
PubMed, and EMBASE databases using
the keywords “pregnancy” OR “gestation”
AND “sudden sensorineural hearing loss”
OR “sudden hearing loss” OR “sudden
deafness”, and limited the results to
l March 2019. All search results were
merged, and duplicate articles and reviews
were removed. We also searched key article
reference lists to find additional related
publications. We identified 10 articles relat-
ed to our research topic.
Possible etiologies
Hormonal changes
The exact etiology of SSNHL in
pregnant women has not been identified.
Nonetheless, the relationship between hor-
monal changes and hearing loss was fre-
quently discussed in previously published
articles. Production and excretion rates of
sex steroid hormones (estrogen and proges-
terone) are significantly increased when a
woman is pregnant. These female hormonal
changes can cause an electrolyte imbalance
(excessive salt and water retention), which
leads to an apparent increase in the volume
of extracellular fluid.
8–10
Previous studies
have shown widespread expression of estro-
gen receptors in humans and rodent cochle-
ae.
11,12
When hormonal fluctuations occur
in the cochleae, the chemical compositions
(e.g., concentrations of sodium) of endo-
lymph and perilymph may also be dis-
turbed. If water–sodium retention occurs
in the endolymph, endolymphatic hydrops
may occur in the cochlea and then SSHNL
may occur when the vestibular membrane
ruptures, which is similar to the pathologi-
cal process of Me
´nie
`re’s disease.
6,9
On the
basis of this hypothesis, Hou and Wang
5
defined this clinical problem as a new dis-
ease related to pregnancy called pregnancy-
induced SSNHL, which is different from
non-pregnant SSNHL. Although many
studies have suggested that sex steroid
hormones may interrupt cochlear microcir-
culation and cause sudden hearing loss,
correlation analysis between the level of
sex hormones and hearing loss still remains
uncertain.
3
2Journal of International Medical Research

Cardiovascular and
hematological changes
Anatomically, the cochlea is supplied by the
labyrinth artery. As a terminal artery, the
labyrinth artery is vulnerable to vascular
occlusion. Accordingly, most changes in
the cardiovascular system and hematologi-
cal system occur in the second month of
pregnancy, and plateau in the second or
third trimester.
13
There is usually a rise
in some coagulation factors (VII, VIII, IX,
X, XII) and fibrinogen, and a fall occurs
in factor XI in pregnancy.
5
Therefore,
a hypercoagulable state with increased acti-
vation of blood coagulation and the fibri-
nolysis system appears during normal
pregnancy. However, these changes in the
hypercoagulable state could increase
plasma viscosity and erythrocyte aggrega-
tion, and decrease erythrocyte deformabil-
ity in pregnant women. This may lead to an
increase in the risk of thromboembolism
in the labyrinth artery and vascular occlu-
sion in the cochlear microcirculation,
5,13,14
and may further evoke SSNHL.
Immune-mediated disorders
According to previous reports, SSNHL is
sometimes associated with acquired auto-
immune system disorder.
15–17
Wiles et al.
17
reported two cases of SSNHL with antiphos-
pholipid (AP) antibodies and discussed the
probable causative association. As an auto-
immune disease, AP syndrome is defined by
the presence of AP antibodies or anticardio-
lipin antibody in association with vascular
thrombosis and/or pregnancy-related com-
plications. AP syndrome can cause thrombo-
sis in the cochlea, placenta, and vessels, and
this subsequently leads to SSHNL and
abortion.
16,17
Other etiologies
Acoustic neuroma is reported in up to 15%
of patients with SSNHL and thus might be
an etiology of SSNHL during pregnancy.
6,18,19
During the last 3 or 4 months of gestation,
hormonal changes may rapidly enlarge
acoustic neuroma. A gradual increase in
volume of the acoustic neuroma and vascu-
larity of the vestibular nerve myelin sheath
can then commence or worsen the symp-
toms of acoustic neuroma, and even evoke
SSNHL.
20
Moreover, undesirable lifestyle
habits and stress during pregnancy might
increase the risk of SSNHL.
3,5
Hou and
Wang
5
also found that a pregnant patient
suffered from SSNHL after emotional exci-
tation. In 2008, Pawlak-Osinska et al.
21
pre-
sented a case of repeatable SSNHL in a
woman during her first and second preg-
nancies. These authors speculated that suf-
fering sudden deafness in the first
pregnancy is a risk factor of another occur-
rence during following pregnancies.
Clinical manifestations and examinations
A few case series studies involving pregnant
SSNHL have been published, and the total
number of patients was less than 150
(Table 1). A study in Taiwan showed that
most cases of SSNHL during pregnancy
occurred in the last trimester, and younger
pregnant women had a relatively lower
occurrence of SSNHL than did older preg-
nant women.
3
In a retrospective analysis
of pregnant SSNHL from the south of
China,
18
clinical manifestations of pregnant
patients with SSNHL showed that 57% had
moderate hearing loss and 38% reached
severe or profound deafness. Additionally,
all of the pregnant patients in this study
were in the last two trimesters. According
to previous studies with detailed informa-
tion of clinical manifestations (Table 1),
more than 80% of pregnant patients with
SSNHL suffered from this problem in the
second or third trimester. Moreover, most
pregnant patients were primiparas without
systemic disease or precipitating fac-
tors.
3,6,18
Hearing loss in most pregnant
Xie and Wu 3

Table 1. General information of pregnant patients with SSNHL from previous studies.
References
Patients
(n)
Age
(years)
Trimester
during
pregnancy
Affected
ear side,
left,
n (%)
Onset of
hearing loss
Initial
hearing
threshold
(dB)
Characteristics
of hearing
loss
Co-existing
symptoms
Oral
steroids
Intratympanic
steroids (times)
Dextran
40 iv
Other
treatment
Final hearing
threshold (dB)
Outcome
(Siegel’s
criteria) Notes
1
23
6 30.34.5
(26–37)
2 in the
second
and 4 in
the third
5 (83.3) 5.35.0
(1–14)
days
90.518.8 Severe to
profound
(n ¼5)
Moderately
severe
(n ¼1)
Tinnitus
(n ¼6)
Fullness
(n ¼3)
Dizziness
(n ¼3)
– All patients
received
intratympanic
dexamethasone
(3–14)
– – 42.514.5
(23–59)
Overall
recovery rate
was 33.3%,
including
16.7%
complete
recovery
and 16.7%
partial
recovery
2
22
30 27.73.3
(21–35)
6 in the first,
14 in the
second,
and 10 in
the third
17 (56.7) 4.83.7
(1–14)
days
63.425.1 Ascending
(n ¼3)
Descending
(n ¼3)
Flat (n ¼12)
Profound
(n ¼12)
Tinnitus
(n ¼21)
Vertigo
(n ¼7)
– 16 patients
received
intratympanic
dexamethasone
(3)
All patients
received
500 mL
dextran-40
per day for
10 days
– 43.725.5
(10–90)
Overall
recovery
rate was
60.0%, includ-
ing 33.3%
complete
recovery
and 26.7%
partial
recovery
3
24
24 28.13.3
(21–35)
4 in the first,
9 in the
second,
and 11 in
the third
14 (58.3) 4.83.8
(1–14)
days
71.821.1 Ascending
(n ¼2)
Descending
(n ¼2)
Flat (n ¼6)
Profound
(n ¼14)
Tinnitus
(n ¼17)
Vertigo
(n ¼6)
Fullness
(n ¼5)
– 13 patients
received
intratympanic
dexamethasone
(3)
All patients
received
500 mL
dextran
40 per day
for 10 days
– No data Overall
recovery
rate was
50.0%, includ-
ing 33.3%
complete
recovery
and 16.7%
partial
recovery
(continued)

Table 1. Continued.
References
Patients
(n)
Age
(years)
Trimester
during
pregnancy
Affected
ear side,
left,
n (%)
Onset of
hearing loss
Initial
hearing
threshold
(dB)
Characteristics
of hearing
loss
Co-existing
symptoms
Oral
steroids
Intratympanic
steroids (times)
Dextran
40 iv
Other
treatment
Final hearing
threshold (dB)
Outcome
(Siegel’s
criteria) Notes
4
19
7 27.43.5
(22–32)
6 in the
second
and 1 in
the third
No data 5 (6 hours
to 12
days)
70.322.2 No data No data þ– All patients
received
500 mL
dextran
40 per
day for
14 days
Low flow
oxygen
42.330.0 Overall
recovery
rate was
71.4%, includ-
ing 14.3%
complete
recovery
and 57.1%
partial
recovery
1 patient
had
acoustic
neuroma
5
18
21 26.23.3
(22–35)
19 in the
second
and 1 in
the third
No data 5 (8 hours
to 15
days)
No data Ascending
(n ¼6)
Flat (n ¼7)
Profound
(n ¼5)
Irregular
(n ¼3)
No data þ– 17 patients
received
500 mL
dextran
40 per day
for 10 days
2 patients
received
puerarin
injection
250 mL
No data Overall
recovery
rate was
76.2%, includ-
ing 61.9%
complete
recovery
and 14.3%
partial
recovery
1 patient
had
acoustic
neuroma,
and 2
were
self-cured
6
5
2 30, 31 2 in the first 1 (50) 7, 10 days 26.3, 96.3 Ascending
(n ¼1)
Profound
(n ¼1)
Tinnitus
(n ¼2)
Fullness
(n ¼2)
– – – One patient
received
HBO and
acupuncture
therapies
12.5, 73.8 Overall
recovery
rate
was 50%,
including
50% com-
plete recovery
1 was
self-cured
7
9
1 42 Third 0 (0) No data 27.5 Ascending – – – – – 21 Complete
recovery
(continued)

Table 1. Continued.
References
Patients
(n)
Age
(years)
Trimester
during
pregnancy
Affected
ear side,
left,
n (%)
Onset of
hearing loss
Initial
hearing
threshold
(dB)
Characteristics
of hearing
loss
Co-existing
symptoms
Oral
steroids
Intratympanic
steroids (times)
Dextran
40 iv
Other
treatment
Final hearing
threshold (dB)
Outcome
(Siegel’s
criteria) Notes
8
21
1 25 (first
time)
Second
(first
time)
0 (0) 2 days 38.8 Irregular
(fluted)
Tinnitus þ– – B vitamins
and
vasodilators
11.3 Complete
recovery
The patient
was
self-cured
at the
second
time
27 (second
time)
First
(second
time)
1 (100) No data 42.5 Irregular
(fluted)
– – – – – 8.8 Complete
recovery
9
25
6 30.5
(25–35)
2 in the
second
and 4
in the
third
2 (33.3) No data 55.519.8 Ascending
(n ¼1)
Descending
(n ¼1)
Flat 3
Basin
(n ¼1)
Tinnitus
(n ¼6)
Dizziness
(n ¼4)
– All patients
received
intratympanic
dexamethasone
2 patients 4 patients
received
carbogen
23.718.7 Overall
recovery
rate was
66.7%, includ-
ing
50%
complete
recovery
and 16.7%
partial
recovery
10
6
12 28.93.6
(24–37)
4 in the first,
3 in the
second,
and 5 in
the third
8 (66.7) 3 (1–9)
days
83.122.1 No data Vertigo
(n ¼4)
– – 6 patients – 58.829.2 In the
treated group,
the overall
recovery
rate was
33.3%, includ-
ing 16.7%
complete
recovery
and 16.7%
partial
recovery
1 patient
had
acoustic
neuroma;
1 was
self-cured
Siegel’s criteria:
50
complete recovery is a final hearing level better than 25dB; partial recovery is more than a 15-dB hearing gain and a final hearing level between 25 and 45 dB; slight recovery is a final
hearing level >45 dB with a hearing gain of 15 dB; and no recovery is a final hearing level >75 dB with a hearing gain of 15 dB. HBO: hyperbaric oxygen; iv: intravenously; Sudden sensorineural hearing
loss, SSNHL

patients is unilateral and some of them may
also have tinnitus, vertigo, or dizziness, and
fullness of the ear.
5,6,22–25
However, the
irregularity and diversity of these accompa-
nied symptoms appear to be related to a
lack of detailed descriptions in other
studies.
18,19
Studies have reported that audiological
changes are found during pregnancy
because of high levels of sex hormones,
and these changes return to normal once
pregnancy is finished.
8,26
Patients routinely
receive audiometry tests, acoustic immit-
tance, distortion product otoacoustic emis-
sions, auditory brainstem response, and
other audiological examinations for diagno-
sis of SSNHL. Tympanograms are normal
in cases of SSNHL. Zeng et al.
18
analyzed
the audiometric curves of 21 pregnant
patients and found that 57% (12/21) of
patients showed moderate hearing loss.
Furthermore, 38% (8/21) of patients
reached severe or profound deafness, and
most of them were in a low-mid frequency
falling curve (n ¼6) and flat curve (n ¼7).
However, in some recent studies, such as
those by Xu et al
22
, Fu et al.
23
, and Shi
et al.
24
, most pregnant patients suffered
from severe or profound deafness.
Treatments
The equivocal etiologies of SSNHL lead
to many empirical treatment protocols
for these patients. However, the most fre-
quently recommended therapy for SSNHL
is systemic or topical administration of
steroids and hyperbaric oxygen (HBO)
therapy.
27
Prescriptions of other medicines
(e.g., antivirals, thrombolytics, vasodila-
tors, vasoactive substances, and antioxi-
dants) to patients are not recommended.
However, the therapeutic strategy for preg-
nant patients with SSNHL is particularly
challenging because of the limited clinical
experience. Otolaryngologists should con-
sider whether there are sufficient benefits
to pregnant patients with SSNHL when
they attempt to save their hearing by
taking the risk of exposing the fetuses to
side effects.
3
Previous studies have reported
that hearing of a few pregnant patients
returned to normal levels several days
later or after delivery without any treat-
ment.
5,6,18,21
Because of the fear of mater-
nal complexity and side effects on the
fetuses, as well as the self-cure tendency in
some cases of SSNHL, some pregnant
patients and otolaryngologists prefer
no medication and choose conservative
treatment, including bed rest and carbogen
therapy.
28
However, even though some
cases may spontaneously recover after
delivery occurs, emergency treatment is
mandatory for ethical reasons. Therefore,
many other otolaryngologists advocate pos-
itive treatment.
22,23
The interval between
the initial treatment and onset of hearing
loss is less than 10 days in many pregnant
patients (Table 1). Although SSNHL has
the tendency of spontaneous self-cure in
adult men and non-pregnant women, the
natural course of SSNHL during pregnancy
has not been established.
10
Optimum
management of this clinical problem is con-
troversial. The following empirical thera-
pies can be considered on the basis of
previous studies.
Dextran 40
In the clinic, dextran 40 is widely and
successfully used as a plasma expander for
thrombotic diseases and flap transplanta-
tion. Dextran 40 decreases blood viscosity
and enhances the microcirculation in guinea
pigs, and then reduces cochlear hypoxia,
29
Accordingly, patients with SSNHL who
were treated with intravenous dextran 40
showed marked hearing improvement.
6,30
In Wang and Young’s study,
6
intravenous
dextran 40 treatment led to remarkable
improvement in the hearing of six pregnant
patients with SSNHL These authors also
Xie and Wu 7

found a significant difference in hearing
improvement between the dextran 40
group and control group. Unfortunately,
some adverse effects (e.g., coagulopathy,
acute renal failure, or non-cardiogenic pul-
monary edema) have been reported when
dextran 40 was used as a therapy of
SSNHL.
31
However, there is no apparent
adverse effect of dextran 40 when used as
a therapy for pregnant SSNHL.
6,18,19,22,24
Therefore, the therapeutic benefits probably
outweigh the potential risk of dextran 40 in
pregnant patients and their fetuses.
Corticosteroid therapy
Another alternative treatment for SSNHL is
corticosteroid therapy, including systemic cor-
ticosteroids and topical corticosteroids.
15,27,32
Corticosteroids work via reduction of
inflammation and the immune response, a
change in the mircrovascular circulation,
and a direct effect on sensory epithelium
of the cochleae.
15,32
Despite promising ther-
apeutic effects, this therapy has rarely been
tested on pregnant woman because of det-
rimental fetal effects. Corticosteroids affect
the metabolic and endocrine balance of var-
ious fetal organs after excessive prenatal
exposure of corticosteroids.
33
Therefore,
systemic corticosteroids are not recom-
mended in pregnant women at the first
trimester when the human embryo is most
vulnerable to teratogenic insults.
34
However, corticosteroid therapy is thought
to be safe when corticosteroids are used in
the third trimester according to Ambro
et al.’s prescribing guidelines.
35
Zeng
et al.
18
and Zhang
19
also showed that oral
prednisone use in pregnant women with
SSNHL achieved a satisfactory recovery.
There were also no apparent harmful side
effects found in the mothers and infants
who were followed up for several years.
Intratympanic corticosteroids are increas-
ingly used in patients with SSNHL as a top-
ical corticosteroid therapeutic option,
especially in patients in whom systemic
corticosteroids are contraindicated or
declined
32,36
This therapy is also recom-
mended as initial therapy for severe and pro-
found SSNHL by some otologists.
37,38
Treatment of topical intratympanic cortico-
steroid injection provides a high dose of cor-
ticosteroids in the perilymph through the
intact round membrance.
37,38
The cochlear
pharmacokinetics of intratympanic cortico-
steroids have been confirmed in animal
models.
39
This therapeutic method is rela-
tively easy to carry out under local anesthe-
sia in an outpatient clinic or ward, and it is
well tolerated by the patients. Most patients
can understand the concept of intratympanic
corticosteroid treatment and readily accept
this therapeutic method.
36
Intratympanic
corticosteroid injection is superior to system-
ic administration of corticosteroids because
it not only provides topical high-dose thera-
peutic effects in the affected ear, but it also
avoids the harmful side effects of systemic
concentrations of corticosteroids.
32,36,37,39
Traditionally, dexamethasone and methyl-
prednisolone have been used in intratym-
panic injection, but methylprednisolone
(US FDA category B) may be more suitable
than dexamethasone (US FDA category C)
for pregnant patients. Previous studies have
shown that pregnant patients with SSNHL
can achieve complete or partial recovery
without any side effects after intratympanic
corticosteroid injection.
22–24,40
Fu et al.
23
showed that all of their six patients showed
relatively satisfactory improvement in hear-
ing after intratympanic corticosteroid injec-
tion, and the mean improvement in hearing
was 48 7.33 dB. Therefore, intratympanic
corticosteroid therapy should be recom-
mended to pregnant patients with SSNHL.
Chinese herbal medicine
Chinese herbal medicine is popular with
patients with sudden deafness in China
and other East Asian countries.
41
Chinese
8Journal of International Medical Research

herb extracts, especially puerarin and ginkgo
biloba extract, are most frequently used in
clinical practice.
18,41
Unfortunately, most of
these herb extracts cannot be used in preg-
nant patients, and only puerarin has been
proven to be safe.
18,42
Zeng et al.
18
showed
a satisfactory improvement in hearing in two
pregnant patients with SSNHL after a
course of intravenous puerarin (14 days).
HBO therapy
HBO therapy is recommended to use as an
adjuvant treatment for SSNHL in non-
pregnant patients.
43,44
However, HBO ther-
apy during pregnancy is controversial in the
clinic because of the potential adverse
effects of hyperoxic exposure, such as reti-
nopathy of prematurity, teratogenicity, and
cardiovascular adverse effects, which may
occur in the fetus.
45
However, careful
review of clinical studies has suggested
that a short duration of hyperoxic exposure
during HBO therapy can be well tolerated
by the fetus in all stages of pregnancy.
45
There is no evidence of harmful human
neonatal outcomes with HBO therapy at 2
atmospheres for 2 hours’ duration.
46
Xiao
et al.
47
subjected pregnant rabbits to lipid
peroxidation during late pregnancy and
treated them with HBO therapy. No delete-
rious effects of this treatment on the fetuses
were observed. In the clinic, a pregnant
patient with SSNHL received HBO therapy
in the first trimester.
5
There was no
improvement in hearing at the time of hos-
pitalization, and no adverse effects to the
newborn were observed after cesare-
an delivery.
Other therapies
Traditional Chinese approaches, including
acupuncture and ocular needling, are
thought to be beneficial in patients with
SSNHL.
48,49
In Hou and Wang’s
5
study,
the symptoms of tinnitus and aural fullness
disappeared in a pregnant patient with
SSNHL after treatment with HBO and acu-
puncture for 7 days. However, there was no
improvement in the hearing threshold.
When a pregnant patient with SSNHL
was diagnosed with acoustic neuroma via
magnetic resonance imaging, multidiscipli-
nary therapy was required involving otolo-
gists, neurosurgeons, obstetricians, and
anesthetists.
6
Additionally, management
depended on the trimester of pregnancy
and neurological status.
Prognosis
Various prognostic factors have been
assessed to predict recovery from SSNHL,
including age, onset of hearing loss, initial
hearing loss, types of audiogram, accompa-
nying symptoms, therapeutic method, and
systemic diseases, such as diabetes mellitus
and hypertension.
22,24,43
However, there is
no relevant case series research on the prog-
nosis of SSNHL during pregnancy.
According to previous studies (Table 1),
most pregnant patients with SSNHL
achieved complete or partial recovery after
treatment according to Siegel’s criteria.
50
The short interval between initial treatment
and onset of hearing loss may be associated
with favorable recovery of hearing in preg-
nant patients. However, further studies need
to be performed to determine this issue.
Summary
SSNHL is a relatively rare disease during
pregnancy with different inconclusive etiol-
ogies, irregular clinical features, and equiv-
ocal audiological findings. A thorough
medical history, detailed ear, nose, and
throat examination, and appropriate audi-
ological evaluation are mandatory for
SSNHL. In addition to an ear, nose, and
throat examination, an examination by an
obstetrician is also important. Blood tests
should be performed, including a routine
Xie and Wu 9

blood test, biochemical blood test, clotting
factors, erythrocyte sedimentation rate, sex
hormone analysis, and antiphospholipid anti-
bodies. Imaging examinations of the brain
and inner ears should be carried out to rule
out an acoustic neuroma when acute hearing
loss occurs or within 3 months after delivery.
Most patients suffer from SSNHL in the
second or third trimester, and show moderate
to profound hearing loss. The interval
between the initial treatment and onset of
hearing loss is less than 10 days in most
patients. Some patients exhibit tinnitus, ver-
tigo, or dizziness, and fullness of the ear.
For medical treatment of SSNHL, intra-
venous dextran 40 can be used after carefully
weighing the therapeutic benefits versus side
effects. Intratympanic corticosteroid injec-
tion, as a safe and topical therapeutic
option, also should be recommended to
pregnant patients with SSNHL. Systematic
corticosteroid therapy can be used at the
third trimester. Intravenous puerarin is
another alternative treatment for SSNHL
during pregnancy. The safety and effective-
ness of HBO therapy for pregnant SSNHL
needs to be further confirmed. Overall, treat-
ment of intravenous dextran 40 combined
with intratympanic corticosteroid is proba-
bly a safe and effective therapeutic strategy
for pregnant patients with SSNHL at the
present stage. Much more knowledge is
required about the etiology and clinical man-
ifestations of SSNHL. Additionally, further
clinical research is necessary to identify the
best therapeutic strategy for this clini-
cal problem.
Declaration of conflicting interest
The authors declare that there is no conflict
of interest.
Funding
This study was supported by the Natural
Science Foundation of Hunan Province
(Grant no. 2018JJ3842) and the Natural
Science Foundation of China (Grant
no. 81300819).
ORCID iD
Xuewen Wu https://orcid.org/0000-0001-
7271-7965
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