Background/Aim: The national hearing screening program is applied in newborns. It is reported that the type of anesthesia applied to mothers during delivery may affect hearing screening tests in newborns. In this study, we investigated whether maternal demographic characteristics, type of anesthesia applied to mother, and type of delivery are related to hearing screening test results in newborns
Materials and Methods: A cross-sectional study of hearing screening tests performed between 01.05.2017-30.04.2019 within the scope of the national newborn hearing screening program, which was born in İstanbul Meltem Hospital, was conducted. Retrospectively, hearing screening data of a total of 2452 newborns were included in the study.
Results: 1977 (80.63%) of the newborns were successful in the first otoacoustic emission test phase. With the addition of those who passed the second otoacoustic emission test phase, this number rose to 2389 (97.43%). After the auditory brain response test, the number of those who passed the hearing screening test increased to 2447 (99.80%) in infants. There was no statistically significant difference between neonatal hearing screening test results and mothers’ birth age, gestational week, anesthesia types, and sex of babies (p> 0.05). The no pass rate of TOAE1 is higher in cesarean section than vaginal delivery. This results improved significantly with the second emission test after 1 week. Detailed information should be given to avoid unnecessary distress in the families of newborns who fail at the first test. The timing of the screening protocol used in neonates should be reassessed
Keywords: Delivery Mode; National Newborn Hearing Screening; Transient Evoked Otoacoustic Emissions; Type of Maternal Anesthesia
The incidence of congenital hearing loss is between 1 and 6 per 1000 live births . Further studies have shown that cognitive and academic deficits in babies with hearing loss will cause secondary behavioral adjustment problems [2,3]. National hearing screening programs were first launched in the United States in March 1993 . In 1994, the first newborn hearing screening started at Marmara University in Turkey. National, The National Newborn Hearing Screening, was initiated in 2004. The screening aims to ensure that all newborns are subjected to the transient evoked otoacoustic emissions (TEOAE) within the first 72 hours . The World Health Organization and the Hearing Loss Committee recommend that rehabilitation should be initiated within the first six months after drawing attention to the first 3 months after birth for the detection of hearing the loss in children . These tests are non-invasive and objective tests. It has been shown that children with hearing loss are detectedwithin the first 3 months and if the necessary rehabilitation is applied before 6 months, the expressive language tests of these children at the age of 3 are found to be within normal limits . The National Hearing Screening Program uses TEOAE and Auditory Brainstem Response (ABR) tests in Newborns . Newborns do not pass these tests can be referred to the upper center. False-positive results are sometimes obtained in these tests. False-positive results require repeated hearing screening tests. In infants who do not pass the TOAE test, the test is repeated after a while. ABR test is performed in infants who do not pass these tests.
This creates anxiety and stress in the baby family. Therefore, it is very important to isolate the factors that may affect the results of newborn hearing screening programs . Cesarean section (CS) saves lives, but CS rates above the 15% ceiling recommended by the World Health Organization (WHO) in the most developed countries appear to be remarkable . The OECD (Organization
for Economic Cooperation and Development) report reports
that the CS rate increased from 14.4% in 1990 to 25.8% in 2009
. In addition to increases in obstetric risk factors, including
those associated with delayed and multiple infant pregnancies
and maternal obesity, the increase in CS is higher . Studies
have shown that CS rates are affected by biological, genetic, and
medical factors . It has been reported in the literature that
CS lead to cognitive problems of children . Mothers can be
anesthetized both during cesarean section and during delivery.
There are reports that the type of anesthesia applied to mothers
may affect hearing screening tests in newborns [9,15]. It is very
important to isolate and categorize factors that may affect the
success or failure of hearing screening programs. In this study,
we investigated whether maternal demographic characteristics,
type of anesthesia applied to the mother, and type of delivery
were related to hearing screening test results in newborns.
This study is a cross-sectional study of hearing screening
tests performed within the scope of National Hearing Screening
Program of newborns born in Istanbul Meltem Hospitalbetween 01.05.2017-30.04.2019. As it was a retrospective study,
informed consent was not obtained from the patient, and local
ethics committee permission was obtained (Date: 31.05.2019
No: 2019/37). Infants having any of the risk factors identified
by the Joint Committee on Infant Hearing of the American
Academy of Pediatrics in 1994 (Table 1); infants who remain in
the intensive care unit with or without mechanical ventilation
after delivery; Infants born before <35 weeks of gestation;
babies with diagnosed congenital health problems; infants with
preeclampsia or eclampsia during pregnancy in the mother were
excluded from the study. In 1994, the risk factors defined by
the American Academy of Pediatrics Infant Hearing Committee
(Items were taken from the Joint Committee on Infant Hearing
1994 Position statement) and were tabulated  (Table 1).
Neonatal hearing screening tests were performed by experienced
audiometrist in a quiet environment in the neonatal hearing
screening unit of the hospital. All tests were performed by the
same audiometrist. Care was taken to keep the babies quiet and
put them on a stretcher during screening. When screening tests
were performed in our hospital, the risk factors listed in Table 1
were questioned and recorded in the file of all infants.
If amniotic fluid or vernix caseosa accumulates in the external
auditory canals, a catheter with a diameter of the canal was
inserted into the external auditory canal, and the screening tests
were performed. For TOAE and ABR tests, Madsen AccuScreen
(GN Otometrics A / S, Taastrup, Denmark) was used. The tests
were performed based on the screening protocol valid at the
time the study data were collected. The first transient evoked
otoacoustic test (TOAE1) was performed on the first day after
delivery before the newborn was discharged. Those who did not
pass this test were invited to the second emission test (TOAE2)
one week later; Those who did not pass TOAE2 were invited
to ABR test 10 days later. Babies who failed the ABR test were
referred to a tertiary care center for further hearing tests. If
babies born in our hospital are born with vaginal delivery (VD),
24 hours after delivery; if they were born by CS, 48 hours after
delivery, they were directed to the Neonatal hearing screening
unit to perform TOAE1. Therefore, all TOAE1 tests wereperformed within the first 48 hours after birth. A total of 3105
newborns were screened. Infants with any exclusion criteria
in the hearing screening files were excluded from the study.
Hearing screening data of a total of 2452 babies were included
in the study. Birth types and newborn gender; Age of mothers
and gestational weeks are listed. The babies were divided into
two groups as VD and CS. The ages of the mothers, gestational
weeks, types of anesthesia (those born with VD, those who had
epidural anesthesia and delivered by CS, those who delivered by
CS, spinal anesthesia, general anesthesia) and newborns were
Of the 2.452 babies, 919 (37.48%) were born by VD, and
1533 (62.52%) were born by CS. 1977 (80.63%) of the newborns
passed the screening test at the TOAE1 stage. With the addition
of those passing the TOAE2, this number rose to 2389 (97.43%).
The number of babies who passed the hearing tests increased to
2447 (99.80%) after the ABR test in babies who did not pass the
transient evoked otoacoustic tests. Hearing loss was suspected
in 5 (0.20%) babies, and these babies were referred to a tertiary
health care facility. When the analysis of the tests was done
according to the type of birth, the results were as shown in Table
2. 87.27% (802/919) of babies born with VD passed the TOAE1test. The ratio increased to 97.93% (900/919) with the addition
of TOAE2 testers. The ratio increased to 97.93% (900/919) with
the addition of TOAE2 testers. The rate of passing the test was
99.78% (917/919) after ABR testing of newborns from TOAE2.
As a result, only 0.22% (2/919) of the babies born with VD were
transferred to the tertiary health care facility from all tests.
76.65% (1175/1533) of babies born with CS passed TOAE1 test.
The ratio increased to 97.13% (1489/1533) with the addition of
the TOAE2. After the ABR test, the pass rate increased to 99.80%
(1530/1533). As a result, only 0.20% (3/1533) of babies born
by CS were passed from all tests and referred to a tertiary health
The difference between the number of newborns remaining
in the TOAE1 stage between the two groups was statistically
significant (p <0.05). After adding the number of testers in TOAE2
stage, no statistically significant difference was found between
the two groups (p> 0.05). No statistically significant difference
was found between the two groups which were referred to the
third step (i.e., all the tests) (p> 0.05). Of the 2 babies who were
born with VD, 1 failed to screen in 1 ear and 1 failed in 2 ears. Of
the 3 babies who were born with CS, 1 failed to screen in 1 earand 2 failed in 2 ears. False-positive rates were high (12.73% -
23.35%) in the first hearing screening in both delivery types and
significantly decreased in the second screening (2.07% - 2.87%)
(Figure 1). Accordingly, it was observed that most of the babies
passed the screening test at TOAE2 stage, and there was no
statistically significant difference in terms of delivery type (p =
0.417). There was no statistically significant difference between
the mothers’ age at birth, gestational week, anesthesia types and
sex of babies and hearing test results (p> 0.05).
Hearing screening program is the method that can detect
early hearing loss in newborns. Tests to be used in screening
programs should be interpreted as easily and quickly as
possible. TOAE and ABR tests performed within the framework
of the national hearing screening program are non-invasive and
easily reproducible tests . Determining factors that may
affect screening test results will lead to the development of these
programs. In this study, we compared the results of neonatal
hearing screening with the factors related to mother and baby.
Failure of TOAE1 was higher in newborns born by CS. In both
delivery modes, it was seen that the majority of newborns
completed the test at the TOAE2 stage. Almost all of those who
failed in TOAE2 completed the screening in the ABR phase. After
all stages, no correlation was found between hearing screening
test results and mode of delivery. Smolkin et al.  reported
that the risk of failure of TOAE1 in infants born by CS increased
approximately 3.2 times compared with VD. In this paper, the
result was associated with amniotic fluid accumulation in the
middle ear . In a similar study, Xiao at all. found significantly
higher failure rates in CS in TOEA1. They suggested that this
difference could be seen in babies born by CS due to delayed
absorption of middle ear fluid . They grouped the results
of TOAE1 according to screening timing, indicating that those
patients screened in the first 42 hours showed even higher
failures than those screened at later hours. However, the rates
they found were not statistically significant .
Olusanya  in their study on Nigerian newborns born
with VD compared to those born with CS, they are two times
the risk of hearing loss, he said. As a result, they attributed
Nigerian pregnant women to increase the risk of birth trauma
by spending more than necessary labor for VD. In the same
study, babies with hearing loss were associated with low Apgar
scores . Farahani et al.  It has been reported that hearing
loss results after hearing screening tests are 1.5 times higher
in VD than those performed by CS. The authors attributed this
difference to incorrect tympanic membrane mobility in infants
born by VD, thereby delaying the absorption of middle ear fluid.
He stated that false-positive rates decreased in time with CS
but did not see such a decrease in those born with VD . In
the same publication, they reported that false-positive rates
decreased significantly in TOAE2 tests performed two weeks
after birth and that there was no significant difference in terms
of delivery mode . In the study of Güven, it was stated that
those who delivered by CS were more unsuccessful in TOAE1, but
the rate of failure decreased as the hour passed in both delivery
modes . In the same publication, tests performed after the
60th hour of labor were compared, and it was stated that there
was no significant difference between failure rates in terms of
delivery modes over time . In another study, Smokin et al.
 emphasized that performing TOAE1 screening 48 hours
after birth will reduce the failure rates .
In our study, it was found that failure rates in TOAE1
decreased in both forms from birth to screening time. In infants
who failed the TOAE1 test, otoacoustic emission tests were
repeated before discharge. The results of the second screening
showed low failure rates over time. However, failure rates after
TOAE1 were higher in CS. Failure rate after CS after TOEA1 was
23.35% and 12.73% for VD. The difference was statistically
significant. TOAE2 results, ABR test results, and rates of infants
with hearing loss referred to a tertiary care facility were similar
in both delivery groups. After the ABR tests, the number of
infants who did not pass the hearing screening test decreased
significantly. Because failure rates in TOAE1 have declined over
time and TOAE2 results are similar in the two groups, we think
this is probably due to low tympanic membrane mobility in the
middle ear or amniotic fluid accumulation in the early postnatal
period. We believe that the failure rate of TOAE1 is higher in
CS, and tympanic membrane motility is better in VD. As time
passes, the amniotic fluid is absorbed. Accordingly, the TOAE2
test performed after 1 week shows that the failure rates of
both births are close to each other. Sequi-Canet  results are
similar to our results.
These authors found that babies born with VD were more
successful in TOAE1 with early onset of breastfeeding. Torrico et
al.  recommended that it should be done as late as possible 48
hours after birth in order to increase the success rate in TOAE1
test and recommended that repeat should be done at least six
days after the first test in case of failure. The data analyzed in
this study show that the delivery type does not affect the success
of newborn hearing screening tests. However, TOAE1 results are
related to the way newborns are delivered. Possible amniotic
fluid in the outer ear and middle ear may affect the success of
TOAE1 screening in the early postnatal period. In one study, it
was reported that the removal of external ear rash increased the
rate of TOAE transition from 76% to 91% . Cavanaugh et al.
 Reported that tympanic membrane mobility was limited in
most newborns and that 93% had normal tympanic membrane
appearance (pink or gray color) in most neonates. Diaz et al.
 showed that maternal lidocaine hydrochloride anesthesia
produced a significant delay in brainstem auditory evoked
responses in newborns born by CS. Khoza et al.  stated that
epidural anesthesia applied four hours before birth increased
the frequency of false-positive results in hearing screening tests.
In our study, no relationship was found between anesthesia
types applied to mothers in VD and CS and hearing screening
test results of newborns. Epidural anesthesia for mothers in
VD in our hospital is rare; the fact that the majority of CS was
performed with spinal anesthesia may have been effective in this.
In this study, false-positive results in TOAE1 are common, with a
higher rate in babies born by CS. It should be remembered that
false-positive results may cause anxiety and stress in the family.
Families should be well informed about this, and it should be
stated that the important result will be said after the completion
of all tests. Care should be taken to ensure that screening testsare performed properly and on time. Infants who fail hearing
screening tests should be referred to as tertiary health care
facilities without delay. The timing of TOAE1, where falsepositive
results are frequently encountered, should be planned
as late as possible just before the baby is discharged.
The type of delivery in newborns and the type of anesthesia
applied to their mothers do not affect hearing screening test
results. The failure rate of the first otoacoustic emission tests is
higher in cesarean-born infants. This result, which was evaluated
as false-positivity, was significantly improved by the second
transient evoked otoacoustic test after 1 week. In particular,
the families of newborns who failed the first transient evoked
otoacoustic test should be given detailed information to avoid
unnecessary sadness. Furthermore, the timing of the screening
protocol used in neonates should be reassessed
Cunningham M (2003) Cox e, Committee on Practice and Ambulatory Medicine and the Section on Otolaryngology and bronchoesophagology. Hearing assessment in infants and children: recommendations beyond neonatal screening. Pediatrics 111: 436-440.
Kepekçi AH (2018) Section 2: Sub-Fields in Audiometry. Audiometry: Hearing and Measurement Vestibular System, Neurotology: Nobel Medical Bookstores pp. 105-124.
Gibbons L, Belizán JM, Lauer JA, Betrán AP, Merialdi M, et al. (2010) The global numbers and costs of additionally needed and unnecessary caesarean sections performed per year: overuse as a barrier to universal coverage. World health report 30: 1-31.
Indicators O (2015) Health at a Glance 2011. OECD Indicators, OECD Publishing, Paris.
Farahani F, Nahrani MH, Seifrabiei MA, Emadi M (2017) The effect of mode of delivery and hospital type on newborn hearing screening results using otoacoustic emissions: based on screening age. Indian Journal of Otolaryngology and Head & Neck Surgery 69: 1-5.
Güven SG (2019) The Effect of Mode of Delivery on Newborn Hearing Screening Results. Turkish archives of otorhinolaryngology 57: 19.
Smolkin T, Awawdeh S, Blazer S, Mick O, Makhoul IR (2013) Delayed first otoacoustic emissions test decreases failure on neonatal hearing screening after caesarean delivery. Acta Paediatrica 102: e194-e199.