Is Asian ethnicity an independent risk factor for
severe perineal trauma in childbirth? A systematic
review of the literature
Janet Wheelerb,*, Deborah Davisa, Margaret Frya, Pat Brodiea,
Caroline S.E. Homera
aFaculty of Nursing, Midwifery & Health, University of Technology, Sydney, Broadway, NSW, 2007, Australia
bLiverpool Hospital, Sydney South West Area Health Service, Elizabeth Street, Liverpool, NSW, 2170, Australia
Received 14 January 2011; received in revised form 11 July 2011; accepted 3 August 2011
In most settings, perineal trauma is a common form of
morbidity associated with childbirth.1The incidence of
severe perineal trauma, which disrupts the anal sphincter
(see Table 1 for definitions) was thought to be 0.6—9%2,
Women and Birth (2012) 25, 107—113
Severe perineal trauma;
Anal sphincter laceration;
Objective: To undertake a systematic review of the literature to determine whether Asian
ethnicity is an independent risk factor for severe perineal trauma in childbirth.
Method: Ovid Medline, CINAHL, and Cochrane databases published in English were used to
identify appropriate research articles from 2000 to 2010, using relevant terms in a variety of
combinations. All articles included in this systematic review were assessed using the Critical
Appraisal Skills Programme (CASP) ‘making sense of evidence’ tools.
Findings: Asian ethnicity does not appear to be a risk factor for severe perineal trauma for
women living in Asia. In contrast, studies conducted in some Western countries have identified
Asian ethnicity as a risk factor for severe perineal trauma. It is unknown why (in some situations)
Asian women are more vulnerable to this birth complication. The lack of an international standard
definition for the term Asian further undermines clarification of this issue. Nevertheless, there is
an urgent need to explore why Asian women are reported to be significantly at risk for severe
perineal trauma in some Western countries.
Conclusion: Current research on this topic is confusing and conflicting. Further research is
urgently required to explore why Asian women are at risk for severe perineal trauma in some
# 2011 Australian College of Midwives. Published by Elsevier Australia (a division of Reed
International Books Australia Pty Ltd). All rights reserved.
* Corresponding author. Tel.: +61 2 46830152.
E-mail address: email@example.com (J. Wheeler).
a va ila ble at ww w. scie nce dir ect. com
jo u rn al h om ep age: w ww.els evier.c o m/lo c ate/wo mb i
1871-5192/$ — see front matter # 2011 Australian College of Midwives. Published by Elsevier Australia (a division of Reed International Books Australia Pty Ltd). All rights reserved.
however, with the use of three-dimensional imaging, studies
in the United Kingdom (UK) and the United States of America
(USA) suggest the incidence may range from 11% to 25%.3,4
Severe perineal trauma can have short and long term impli-
cations for quality of life and wellbeing, therefore, it is
essential to attempt to minimise this adverse outcome.1,5—9
In a maternity unit south west of Sydney, New South Wales
(NSW), Australia, four women experienced severe perineal
trauma following a vaginal birth and required colorectal
surgery. In response, a 12 month retrospective audit of health
care records was conducted (unpublished). This audit iden-
tified that of 2,403 vaginal births, 61 (2.5%) women experi-
experiencing a normal vaginal birth, 31% (n = 19) a vacuum
and 5% (n = 3) forceps. Twenty-five percent of these women
(n = 39)
were born in Australia, almost half were born in an Asian
country and the rest were from other countries. Women born
in Asian countries were over-represented in the findings. The
term ‘Asian’ was used to define any woman born in South East
Asia, China, India or Fiji. This definition was not based on any
literature or classification.
Asian ethnicity has been shown to be a risk factor for severe
perineal trauma in some countries, however, there is still
uncertainty as to whether Asian ethnicity is an independent
risk factor, or if other factors combine with Asian ethnicity to
increase the likelihood of severe perineal trauma. Clearly,
women’s ethnicity cannot be altered, but the identification of
factors related to midwifery practice that might make a
difference to the incidence of this event in Asian women would
be useful. This systematic review examined whether Asian
ethnicity was a risk factor for severe perineal trauma, addres-
sing the question ‘‘Is Asian ethnicity an independent risk factor
for severe perineal trauma in childbirth?’’ A systematic review
of this nature has not been conducted before.
Ovid Medline, CINAHL and Cochrane databases were used, to
identify research articles published in English from 2000 to
2010, using relevant terms in a variety of combinations (Table
2). The Cochrane Library did not provide any further refer-
ences with the terms ‘‘Asian, race or ethnicity’’ or with any
combination of all the above terms entered into Medline. A
hand search of current relevant journals did not find any new
A total of 2,890 articles were identified. A review of
article titles established that 221 articles were relevant to
this systematic review. These articles were further reviewed
in detail for relevancy to Asian ethnicity and risk factors for
Definition for perineal tears.
Injury to perineal skin only.
Injury to perineum involving perineal
muscles but not involving the anal
Injury to the anal sphincter involving
the anal sphincter complex:
3a: Less than 50% of external anal
sphincter (EAS) thickness torn.
3b: More than 50% of EAS thickness torn.
3c: Both EAS and internal anal sphincter
Injury to perineum involving the anal
sphincter complex (EAS and IAS) and
Databases, search terms and number of articles identified and retrieved.
‘‘perine* or sphincter’’ and ‘‘ethnicity or race or Asian’’.
‘‘Asian’’ and ‘‘perine* or sphincter’’. ‘‘Childbirth or birth
or labour’’ with ‘‘Asian’’. ‘‘Childbirth or birth or labour and
‘‘Asian’’. ‘‘Trauma or injury or 3rd degree or 4th degree’’ and
‘‘Asian’’. ‘‘Perine* or sphincter’’ and ‘‘severe and Asian’’.
‘‘Childbirth or birth or labour’’ and ‘‘Severe and Asian’’.
‘‘Severe and Asian’’ and ‘‘trauma or injury or 3rd degree or
4th degree. Severe perineal trauma and risk factors’’.
‘‘Severe perineal trauma’’. ‘‘Perineal trauma’’ and ‘‘Asian or
race or ethnicity’’. ‘‘Third degree or fourth degree or 3rd degree
or 4th degree’’ and ‘‘Asian or race or ethnicity’’. ‘‘Anal sphincter
disruption’’. ‘‘Anal sphincter laceration’’. ‘‘Anal sphincter injury’’.
‘‘Perineal laceration’’. ‘‘Anal sphincter’’ and ‘‘Asian or race or ethnicity.’’
‘‘Perine* or sphincter and Asian or ethnicity or race’’.
‘‘Perine* or sphincter’’ and ‘‘Asian or ethnicity or race.’’ ‘‘Severe and
Asian’’. ‘‘Childbirth or birth or labour’’ and ‘‘Asian’’. ‘‘Childbirth or
birth or labour’’ and ‘‘Severe and Asian’’. ‘‘Childbirth or birth or
labour’’ and ‘‘Asian’’.
‘‘Childbirth or birth or labour’’ and ‘‘Severe and Asian’’. ‘‘Trauma or
injury or 3rd degree or 4th degree’’ and ‘‘Asian’’. ‘‘Trauma or injury
or 3rd degree or 4th degree’’ and ‘‘Severe and Asian’’.
J. Wheeler et al.
severe perineal trauma, and their reference lists were also
searched for related articles, leaving a total of 15 articles for
this systematic review. Articles were excluded if Asian eth-
nicity was not considered independently, or data on Asian
ethnicity was not provided. The methodological quality of
articles located using this screening process was assessed
using the Critical Appraisal Skills Programme (CASP) tool.10
The 15 articles originated from Asia, Australia, Canada, UK
and the USA. One study used data from a randomised con-
trolled trial (RCT) for a secondary analysis.11All others were
either retrospective or prospective observational/cohort
studies. Categories emerged as studies were reviewed and
findings are presented under these category headings.
Being of Asian origin as a risk factor for severe
In the USA, Green and Soohoo12were among the first
researchers to suggest ethnicity may increase the risk of
anal sphincter laceration during vaginal birth. This retro-
spective study of 2,706 spontaneous vaginal births identified
that women of Chinese and Filipino origin were significantly
more likely to have anal sphincter lacerations than White
women. Language barriers and anatomical variation (short
perineal bodies) were thought to be possible reasons for
More than a decade later, the influence of race or ethni-
city on severity of perineal trauma was described in a number
of studies. For example, a USA study estimated the incidence
of anal sphincter laceration and identified risk factors in more
than two million vaginal births from 1992 to 1997.13Multiple,
breech and preterm births and stillbirths were excluded.
Racial or ethnic background was found to influence the
severity of perineal lacerations, with women from Filipina
(OR 1.63; 95% CI 1.50—1.77), Indian (OR 2.5; 95% CI 2.23—
2.79) and Other Asian (OR 1.37; 95% CI 1.29—1.45) groups
being more likely to sustain severe perineal trauma. Ethnicity
was not differentiated within the Other Asian group even
though this group made up 6.5% (129,220) of the total
sample, which is significantly higher than the Indian (0.7%)
and Filipina (2.3%) groups.
In a retrospective cohort study conducted in the USA, first
vaginal birth (OR 6.40, 95% CI, 5.11—8.01), midline episiot-
omy (OR 6.91, 95% CI, 6.06—7.88), forceps birth (OR 4.48,
95% CI, 3.85—5.20), pudendal block (OR 5.63, 95% CI, 4.72—
6.41) and birth weight of more than 4000 g (OR 2.35, 95% CI,
1.91—2.89) were identified as risk factors for severe perineal
trauma.14The severe perineal tear rate was 8.2% (n = 1,905)
from a sample of 23,244 women experiencing a vaginal birth
in one hospital from 1993 to 1998. Asian women (3.4% n = 65)
were found to be at increased risk for a severe perineal tear
(OR 1.75, 95% CI, 1.27—2.41) and experienced more episio-
tomies (36.9% vs. 24.6%). The majority of birth attendants
were junior medical officers and the effect of clinicians
during labour and birth is suggested as possibly influencing
the severity of perineal trauma.
Goldberg et al.15in the USA, examined the association
between maternal race, the incidence of 3rd and 4th degree
perineal tears and the overall rate of perineal trauma in one
hospital. A retrospective study of 34,048 vaginal births from
1983 to 2000 identified that 10% of women had incurred a 3rd
or 4th degree perineal tear. There were 833 Asian women in
this group, confirming that Asian race was an independent
risk factor for 3rd or 4th degree perineal tears (OR 2.04; 95%
CI 1.43—2.92) compared with White race, whereas Black race
(OR 0.42; 95% CI 0.35—0.52) was protective. Asian women
were found to be particularly at risk for anal sphincter injury
if they experienced an instrumental birth and an episiotomy.
The Asian group was described as being mainly Chinese,
included for example, women with Laotian and Vietnamese
Hopkins et al.16attempted to determine whether ethni-
city could enable clinicians to adapt their clinical practice
techniques to minimise perineal trauma. They undertook a
retrospective study to identify variations in ethnicity in
perineal, vaginal and cervical tears following vaginal birth
in nulliparous women. Data were extracted from a database
at the University of California, USA, from 1976 to 2001, and
from a sample of 17,216 births, it was identified that 2,645
(15.4%) women experienced a 3rd or 4th degree tear. Other
Asian (19.3%), Chinese (23.3%) and Filipino (21.9%) groups
had the highest number of 3rd and 4th degree tears. The
Other Asian group included South East Asian, Indian and
Pacific Islander women.
Similarly, in the USA, a retrospective cohort study identi-
fied significant differences in pregnancy and birth outcomes
between Latina (51%), Black (7%), Asian (6.9%) and White
non-Latina (35%) ethnic groups.17Data from 1997 to 1998
were extracted from a state database and 93% of 1,426,854
births were categorised by selected ethnic groups. Reduced
incidence of severe perineal laceration, postpartum haemor-
rhage and major puerperal infection were seen as markers of
good intrapartum care by the authors. Asian women were
significantly more likely to experience an increase in all three
markers including severe perineal lacerations (OR = 1.32;
95% CO = 1.29—1.35). Therefore, the most likely association
with these adverse outcomes is that Asian women receive
inadequate intrapartum care.
Modifiable risk factors, clinical practice and Asian
A number of studies have considered modifiable risk factors
and clinical practice. For example, a retrospective observa-
tional cohort study of all singleton vaginal births at one
hospital in the USA, examined the effects of modifiable risk
factors on severe perineal trauma from 1996 to 2006.18In
total, 46,239 women met the inclusion criteria, with 2.9%
experiencing severe perineal trauma. Risk factors associated
with severe perineal trauma were nulliparity, instrumental
birth, maternal age, birth weight and ethnicity. The inci-
dence of severe perineal trauma between ethnic groups
varied dramatically–—yet again, women of Asian ethnicity
experienced the highest rate of severe perineal trauma at
11.4%, compared with Black (2.5%) and White ethnicities
(4.1%). The overall incidence of severe perineal trauma
reduced from 5.4% in 1996, to 1.3% in 2006. Clinical practice
changed significantly during this time, with modifiable risk
Is Asian ethnicity an independent risk factor for severe perineal trauma in childbirth? A systematic review of the literature 109
factors for severe perineal trauma being an increasing cae-
sarean section rate and reduction in forceps and episiotomy.
The above results support the findings of an earlier retro-
spective study by Kudish et al.19that included 33,842 women.
The study described individual variation in clinical practice
between clinicians and the use of modifiable risk factors
(midline episiotomy and instrumental birth) for severe peri-
neal trauma at one hospital in Canada, from 1996 to 2003.
The effect of these practices on the incidence of severe
perineal trauma was examined for all women experiencing a
singleton, vertex vaginal birth. All births were conducted by
a medical officer. Instrumental birth and midline episiotomy
(individually and combined) significantly increased the risk of
severe perineal trauma for all women. Asian women experi-
enced the highest rate of severe perineal trauma at 21.7%,
followed by White women (12.2%) and Black women (6.6%),
although the sample size for the Asian group was small
(n = 122 no severe trauma, n = 34 severe trauma).
In Australia, a secondary analysis of data from an RCT
focused on perineal outcomes following vaginal birth for
primiparous women from Asian
grounds.11,20Data were collected from 1997 to 2004 in
two maternity units in NSW. All women were cared for by
midwives during childbirth. One-third of this sample were
classified as Asian and Asian women were found to experience
significantly more 3rd or 4th degree perineal tears (11% vs.
4.5%, OR 2.6, 95% CI 1.4—4.7) and episiotomies (18% vs. 8%,
OR 2.4, 95% CI 1.5—0.38) compared with non-Asian women.
Fear and a lack of ability to communicate were areas high-
lighted as requiring further exploration.
Defining ethnicity in determining associations
Definition of ethnicity is challenging in many of the studies,
which means accurate correlation with trauma is difficult to
determine. Individual ethnicity was self-reported by parti-
cipants in some studies12,15,16whereas, in others it is not
clear how race or ethnicity data were obtained.13,14,18,19No
definition of the terms race, ethnicity or specific groups such
as, Asian were provided.
Other research conducted in Australia considered the
issue of ethnic origin. A 2 year prospective cohort study of
all vaginal births (1998—2000) occurred at a NSW hospital,
with the objective of identifying risk factors for 3rd and 4th
degree tears.21In total, 6,595 women were included and a 2%
(n = 134) severe perineal trauma rate over 2 years was shown,
with 91% (n = 122) of these women having 3rd degree tears
and 9% (n = 12) 4th degree tears. Severe perineal trauma was
found to occur more often if women were Asian, had no
health insurance and when interpreters were needed. The
majority (81%) of women were having their first baby (OR 4.6;
95% CI 2.9—7.2). Severe perineal trauma was experienced by
nearly twice as many Asian than non-Asian women (OR 1.9:
95% CI 1.3—2.8). It was felt that Asian women had a tendency
towards shorter perineums, which can become oedematous
and rigid thereby, increasing the risk of perineal trauma. The
term ‘Asian’ was categorised as the woman’s country of
birth. However, categorising Asian women by country of birth
is a limitation of the study, with individual ethnic background
being potentially misrepresented, for example, ethnicity
could be Chinese, and country of birth could be Australia.
In a USA retrospective cohort study foreign-born women
were found to be at increased risk of experiencing perineal
trauma (RR 1.72, 95% CI 1.66—1.75) and an episiotomy (RR
1.32, 95% CI 1.26—1.39).22Asian women experienced more
4th degree tears (RR 26.9, 95% CI 1.78—4.08). Out of a total of
49,904 (USA-born women 73% n = 36,439), foreign-born
women (27% n = 13,465) came from 164 different countries,
with only 2% (n = 829) identifying themselves as Asian. The
majority of women born in what was considered an Asian
country chose the ‘Other’ ethnic classification rather than
Asian, which highlights the importance of sub-group classi-
fications. Possible effects of poor communication or unrec-
ognised culturally specific needs were mentioned.
Research in Asian countries
Research in Asian countries is important to explore as it has
been suggested that outcomes are only poorer for these
women when they live and give birth in non-Asian countries.
Potential risk factors and incidence of severe perineal trauma
were investigated in 7,946 Japanese women experiencing a
vaginal birth in two hospitals in Japan, from 1997 to 2004.23A
severe perineal tear occurred in 1.7% (n = 135) of women. Risk
factors for severe perineal trauma were found to be midline
episiotomy (OR, 4.65; 95% CI, 2.09—11.55), first vaginal birth
(OR 4.36; 95% CI, 2.17—9.57), forceps (OR, 7.11; 95% CI, 1.95—
20.59), vacuum (OR, 5.93; 95% CI, 3.38—10.36), use of oxyto-
cin (OR, 2.19; 95% CI, 1.27—3.73) and experience of birth
attendant (OR, 2.88; 95% CI, 1.12—9.81). It was reported that
individual clinical practice techniques might have influenced
the incidence of severe perineal trauma. All births were
conducted by medical officers, however, the more experi-
enced the clinician the greater the incidence of severe peri-
neal laceration, which could mean that the more experienced
the clinician, the more complex the birth.
Asian ethnicity as a risk factor for severe perineal trauma
has been described as a ‘‘myth’’ in response to research
findings from a prospective observational study conducted in
Hong Kong.24A policy of restrictive episiotomy was imple-
mented and perineal length was assessed (during the first and
second stage of labour and at crowning) in 429 Chinese
women experiencing a normal vaginal birth at term. Mid-
wives performed an episiotomy only when fetal distress,
maternal exhaustion or a tight perineum (to prevent a peri-
neal tear) was identified. During this study the episiotomy
rate reduced from 73% to 27%, with no subsequent increase in
perineal trauma. Perineal length was found to be comparable
with other ethnicities, which supports the findings of Dua
et al.25Limitations of this study were the small sample size
and the low incidence of severe perineal trauma (0.3%),
which prevented exploration of risk factors.
A Korean retrospective study investigating anal inconti-
nence identified a 2.8% (n = 16) incidence of severe perineal
trauma in a cohort of 562 Korean women experiencing a
vaginal birth at one hospital.26Vacuum birth totalled 160
(28.5%) and eight of these women experienced severe peri-
neal trauma. Generalisability of the study was limited due to
design and a small sample size. These results suggest that
outcomes from studies examining the incidence of severe
perineal trauma for Asian women, living in their Asian coun-
try of origin, appear comparable to studies examining study
J. Wheeler et al.
outcomes of the dominant population in Western countries,
although studies in Asian countries are few and sample size is
small.23,24,26Of concern, is that the risk of experiencing
severe perineal trauma during childbirth appears to drama-
tically increase for Asian women when residing in some
Other possible explanations
Explanations other than ethnicity have been proposed. A USA
retrospective longitudinal study of all singleton births (exclud-
ing episiotomy, multiple and caesarean births) from 2001 to
2006, identified that an increased risk of severe perineal
trauma for Chinese women may be partly due to an imbalance
between maternal body mass index (BMI) and birth weight of
the baby (OR: 1.011; 95% CI: 1.002—1.020)–—this finding is only
just statistically significant.27These combined factors were
found to be more predictive of severe perineal trauma. The
BMI of Chinese women was lower than Hispanic women and yet
in this study the birth weight of babies born to either ethnic
group were comparable (Adj OR 1.0012: 95% CI 1.0007—
1.0016). In total, 3,085 women (1,309 Hispanic and 1,528
Chinese) gave birth in one hospital, with 2,281 (74%) pre-
pregnancy BMI’s available. Only 41 Caucasian, 90 Asian
(non-Chinese) and 117 African American women were in this
cohort. Chinese ethnicity was a significant risk factor for
severe perineal trauma compared with Hispanic ethnicity
(9% vs. 2.8%) (OR: 2.88; 95% CI: 1.92—4.30). BMI:birth weight
ratio does not fully explain why Chinese women are signifi-
cantly more at risk for severe perineal trauma. Anatomical,
social or cultural factors are suggested as being potential
causes although, it is noted that the discipline or influence
of the birth attendants are not mentioned and ability to
effectively communicate is also not considered.
Possible anatomical explanations
Dua et al.25recognised a lack of standardised data for
perineal length during labour and as a result, a prospective
observational study was conducted at a hospital in the UK,
from 2005 to 2007. The aim was to establish a standardised
range for perineal length during the first stage of labour and
show the relationship between perineal length and perineal
tears in Caucasian and Asian women. In total, 1,000 women
were recruited, with the main ethnic origins being classified
as White 73.4% (n = 734) or Asian/Asian-British 25% (n = 250).
The length of the woman’s perineum was measured by a
midwife during the first stage of labour. Participant ethnic
classification was based on UK national standards.28There
was a significant risk of a 3rd degree tear in women with a
short perineum having their first vaginal birth ( p = 0.03). No
significant difference was found in the mean perineal length
between Asian (3.6 ? 0.9 cm) and Caucasian (3.7 ? 0.9 cm)
( p = 0.06; 95% CI 0.01—0.26) women and no association was
identified between maternal BMI, height, weight or perineal
length related to the extent of perineal trauma. Third degree
tears occurred in 2.5% (n = 25) of women (5 Asian, 20 Cau-
casian), with no increased risk attributed to either group.
The authors concluded that Asian and Caucasian ethnicity did
not affect the severity of perineal trauma, which conflicts
with USA and Australian studies, but supports findings in some
Asian studies. However, classification of the term ‘Asian’
applied in this UK study differs from that used in other
countries. In the UK the term ‘Asian’ is applied to people
from the Indian sub-continent.28
The majority of the studies in this systematic review were
conducted in Western countries and describe Asian ethnicity
as a significant risk factor for severe perineal trauma during
childbirth.11,13—16,18,19,21There was an overall severe peri-
neal trauma rate of 2—15.4% for women of all ethnicities,
with women from an Asian background being significantly
more likely to sustain this injury. However, one UK study
found no difference in trauma rates for women with an Asian
or Caucasian background.25Asian ethnicity as a risk factor for
severe perineal trauma has also been described as a
‘‘myth’’,24with studies conducted in Asian countries (Japan,
China and Korea) having a severe perineal trauma rate of
between 0.3% and 2.8%, which is at least comparable or lower
than in Western countries.23,24,26
It has been suggested that Asian women may have a
shorter perineum compared with other ethnic groups and
research has confirmed the shorter the perineum, the more
chance of severe perineal trauma.12,21,25However, no sig-
nificant differences have been found between Asian or Cau-
casian women in perineal length or incidence of perineal
trauma in reviewed Asian and UK studies, in contrast to
research in other Western countries.23—26
Defining the term Asian
Dua et al. classifies ethnic groups based on the UK Ethnic
Group, National Statistics Classification.25,28The terms Asian
or Asian British refer to the following ethnic groups: Indian,
Pakistani, Bangladeshi and Any other Asian background,
whereas in the USA, the term Asian refers to women with
an ethnicity related to South East Asia, the Far East or the
Indian Subcontinent.29Australian standards for defining eth-
nic groups are more in line with the USA classifications,
although they tend to be more specific for example, women
with a South East Asian background can be further delineated
into Mainland South-East Asian and Maritime South-East
Asian, which is further broken down into specific ethnic
groups such as, Vietnamese and Lao or Filipino and Java-
nese.30Combining ethnic groups compromises compatibility
and increases the risk of bias in research.30,31Moreover,
differences in ethnic group classification between the UK,
USA and Australia reduces the generalisability of studies
between these countries and does not support clarification
of Asian ethnicity as a risk factor for severe perineal trauma
in childbirth. Nonetheless, the myriad of definitions used to
describe the term ‘Asian’ globally, should be taken into
consideration when reviewing the literature.
Research has identified known modifiable and unmodifiable
risk factors for severe perineal trauma during childbirth.18,32
Ethnicity has been found to influence the incidence and
severity of perineal trauma during childbirth, with some
ethnicities being protective, whereas others have an
Is Asian ethnicity an independent risk factor for severe perineal trauma in childbirth? A systematic review of the literature 111
increased risk for this complication.11,13,15,16,18,19,27How-
ever, it is recognised that unknown factors continue to
impact on the incidence of severe perineal trauma specifi-
cally for Asian women in Western countries.11,12,14,18,19,21,27
Some studies continue to ponder on what these unknown or
‘‘hidden’’ risk factors might be that create such physical
vulnerabilities in Asian women. Suggestions have been made
that these unknown factors may be related to labour and
birthing management techniques, ethnic anatomical differ-
ences, communication, cultural differences, aculturisation,
fear or influence of the birth attendant.11,12,14,18,19,21,23,27
These factors are occurring within the birthing room setting
and it is suggested that the influence and approach taken by
the birth attendant caring for the labouring and birthing
woman is relatively unknown, particularly when attempting
to minimise perineal trauma for Asian women during labour
and birth. The reviewed studies have no direct observational
data of what is actually occurring within the birthing room.
Studies usually rely on the birth attendant filling in a data
collection form and/or the data is entered into a computer
database following the birth.
Current research on this topic is confusing and conflicting,
and does not provide a definitive answer as to why Asian
women have a significant risk factor for severe perineal trauma
in some Western countries. It is suggested that further
research is required to explore why Asian women are signifi-
cantly at risk for severe perineal trauma in the birth setting.
In summary, Asian ethnicity in some Western countries has
been identified as a significant risk factor for severe perineal
trauma during vaginal birth. However, in contrast to these
findings, Asian women living in an Asian country do not
appear to be significantly at risk for severe perineal trauma.
Potential factors within the birthing room setting may be
influencing the severity of perineal trauma. Additionally, the
lack of an international definition for Asian ethnicity under-
mines generalisability of research results. Nevertheless,
there is an urgent need for research to step into the domain
of the Asian women and birth attendant to explore why some
Asian women are significantly at risk for severe perineal
trauma in the birthing room setting.
There has been no financial assistance with this systematic
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