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\begin{document}

\title{Auricular Acupressure for Pain Relief in Labour : A Systematic Review
and Meta-Analysis}



\author[1]{ZHE WANG}%
\author[1]{Hao Zheng}%
\author[2]{Yanan Li}%
\author[3]{Hao Lv}%
\author[1]{Xiaoyan Wang}%
\author[3]{Jing Han}%
\affil[1]{Shandong University of Traditional Chinese Medicine}%
\affil[2]{Shandong University Qilu Hospital}%
\affil[3]{Shandong University of Traditional Chinese Medicine Affiliated Hospital}%


\vspace{-1em}



  
  \date{June 14, 2024}


\begingroup
\let\center\flushleft
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\endgroup





\selectlanguage{english}
\begin{abstract}
ABSTRACT Background Labour pain ranks consistently among the most severe
types of pain that a woman will experience during her lifetime and leads
harmful effects on both mother and baby. As a complementary method,
auricular acupressure has been used in the pain management for many
diseases and many RCTs showed it has a pain-reliving effect in labour.
However, no meta-analysis has been conducted to provide systematic
evidence for pain relief in labour. Objectives To perform a systematic
review to assess the efficacy of auricular acupressure for labor pain.
Search Strategy PubMed, Cochrane Library, Embase, Web of Science
databases, SinoMed, CNKI, WanFang Data and VIP were searched for studies
using keywords ``auricular acupressure'' combined with ``labor'' and
``RCTs.'' Selection Criteria: Eligible criteria included RCTs, full-text
studies, English, and Chinese literature, whereas exclusion criteria
included incomplete information, duplicated publications, and studies
combined with other analgesic methods. Data Extraction and Analysis: The
selection of eligible items and assessment of methodological quality
were performed independently by two researchers. A meta-analysis was
performed to analyze the treatment effects on pain intensity reduction,
maternal satisfaction and safety. Main Results: 17 RCTs were included in
this review involving a total of 2574 parturients. Auricular acupressure
showed significant efficacy in the reduction of pain intensity and
improvement of maternal satisfaction. Conclusions: Auricular acupressure
showed a pain-relieving effect compared with the routine care. Although
the evidence is limited and high quality studies are needed.%
\end{abstract}%



\sloppy


Auricular Acupressure for Pain Relief in Labour : A Systematic Review
and Meta-Analysis

Zhe Wang\textsuperscript{1\#}, Hao Zheng\textsuperscript{1\#}, Yanan
Li\textsuperscript{2}, Hao Lv\textsuperscript{3}, Xiaoyan
Wang\textsuperscript{1}, Jing Han\textsuperscript{3*}

\textsuperscript{1} College of Acupuncture and Massage, Shandong
University of Traditional Chinese Medicine, Jinan, China.

\textsuperscript{2} Department of Obstetrics and Gynecology, QiLu
Hospital of Shandong University, Jinan, China.

\textsuperscript{3} Department of Acupuncture and moxibustion,
Affiliated Hospital of Shandong University of Chinese Medicine

\# Zhe Wang and Hao Zheng contributed equally to this paper.

*Correspondence:

Jing Han

Address: Department of Acupuncture and Moxibustion, Affiliated Hospital
of Shandong University of Chinese Medicine. No. 16369, Jingshi Road,
Jinan, China

E-mail: \emph{hanjing0127@163.com}

\textbf{ABSTRACT}

\textbf{Background} Labour pain ranks consistently among the most severe
types of pain that a woman will experience during her lifetime and leads
harmful effects on both mother and baby. As a complementary method,
auricular acupressure has been used in the pain management for many
diseases and many RCTs showed it has a pain-reliving effect in labour.
However, no meta-analysis has been conducted to provide systematic
evidence for pain relief in labour.

\textbf{Objectives} To perform a systematic review to assess the
efficacy of auricular acupressure for labor pain.

\textbf{Search Strategy} PubMed, Cochrane Library, Embase, Web of
Science databases, SinoMed, CNKI, WanFang Data and VIP were searched for
studies using keywords ``auricular acupressure'' combined with ``labor''
and ``RCTs.''

\textbf{Selection Criteria:} Eligible criteria included RCTs, full-text
studies, English, and Chinese literature, whereas exclusion criteria
included incomplete information, duplicated publications, and studies
combined with other analgesic methods.

\textbf{Data Collection and Analysis:} The selection of eligible items
and assessment of methodological quality were performed independently by
two researchers. A meta-analysis was performed to analyze the treatment
effects on pain intensity reduction, maternal satisfaction and safety.

\textbf{Main Results:} 17 RCTs were included in this review involving a
total of 2574 parturients. Auricular acupressure showed significant
efficacy in the reduction of pain intensity and improvement of maternal
satisfaction.

\textbf{Conclusions:} Auricular acupressure showed a pain-relieving
effect compared with the routine care. Although the evidence is limited
and high quality studies are needed.

\textbf{Funding:} Health Talents Project of Shandong Province

Keywords: Labor analgesia ;Auricular Acupressure;

Labour pain ranks consistently among the most severe types of pain that
a woman will experience during her lifetime, and 60\% of them complained
their pain as severe or extremely
severe.\textsuperscript{{[}1-2{]}}Besides being unpleasant, the sharp
pain may lead to harmful effects on both mother and baby such as fetal
hypoxia and metabolic acidosis.{[}3{]}

Since the introduction of chloroform for labour analgesia in
1847\textsuperscript{{[}4{]}}, different methods and medications have
been used to relieve the pain of labour, including neuraxial analgesia,
nitrous oxide and systemic opioids. However, the side effects can also
arise from the analgesic process. For example, hypotension occurs during
25\% to 85\% of spinal or epidural anesthetics, and total spinal
anesthesia or local anesthetic toxicity may also
occur\textsuperscript{{[}5{]}}. Accordingly, the non-pharmacologic
techniques like progressive muscle relaxation, breathing, music,
mindfulness have been recommended by WHO as complementary methods for
pain relief during labour.\textsuperscript{{[}6{]}}

Auricular therapy has been used for diagnosis and treatment of diseases
for thousands of years in China. It has developed into a distinct
treatment system since Dr. P. Nogier discovered the correspondence
between the auricle and the internal organs in 1957 He suggested that
the distribution of auricular points was shaped like an inverted
fetus.\textsuperscript{{[}7{]}} Under this theoretical framework, the
auricle is divided into dozens of areas corresponding to different
organs of the body. We can attach magnetic beads or the seed of cowherb
to these special areas to treat different diseases in corresponding
organs. For example, in labour analgesia, we can attach the seeds to the
corresponding points of uterus and pelvis.

For its remarkable efficacy and simplicity, auricular acupressure has
been applied for the treatment of epilepsy, anxiety, obesity, and
insomnia.\textsuperscript{{[}8{]}} A meta-analysis showed it has
positive effects on pain management of several
diseases.\textsuperscript{{[}9{]}}

Many published clinical studies, including randomized controlled trials
(RCTs), have explored auricular acupressure as a treatment option for
labour pain, and most reports have shown positive clinical effects.
However, to the best of our knowledge, no meta-analysis has been
conducted on this topic. In the current review, we assessed the
effectiveness of auricular acupressure for labour pain by using a
meta-analysis.

\textbf{Methods}

This systematic review and meta-analysis (PROSPERO registration No.
CRD42021268033) focused on RCTs involving auricular acupressure
interventions for pain relief during labour.

\emph{1.1 Search strategy.}

We selected relevant studies by searching PubMed, Embase, Web of
Science, Cochrane Library, SinoMed, CNKI, WanFang Data and VIP. We also
searched Chinese Clinical Trial Registry
(\emph{https://www.chictr.org.cn/}) and Clinical Trials.gov
(\emph{https://clinicaltrials.gov/}). All the databases were searched
from inceptions to July, 2021. The search strategy consisted of 3
components: participant (parturition, parturitions, birth, childbirth,
deliveries), intervention (auricular acupuncture, auricular acupressure)
and study type (randomized clinical trial).

\emph{Study Selection}

Two independent investigators (Z.W. and H. Z.) reviewed study titles and
abstracts. Studies that satisfied the inclusion criteria were retrieved
for full-text assessment.

\emph{1.2.1 Inclusion criteria.} Relevant studies were included if the
following criteria were met. (1) Types of studies: randomized controlled
trials (RCTs) with or without blinding. (2) Participants: women intended
vaginal delivery with a fetus at full term. (3) Types of intervention:
with obstetric care routine, treatment groups that received auricular
therapy (including auricular acupressure and auricular acupuncture)
during the whole labour process or only the first stage of labour were
included; we compared ear point therapy with obstetric care routine
during the whole labour process or the first stage of labour. (4) Types
of outcome measures: we included studies that measured pain level,
visual analogue scale (VAS) score, duration of any stage of labour,
maternal satisfaction, neonatal Apgar score, number of spontaneous
delivery cases, number of caesarean section cases and postpartum blood
loss.

\emph{1.2.2 Exclusion criteria.} (1) Duplicate publications. (2) Studies
with incomplete information which was still not available after attempts
to contact the authors. (3) Studies combined other acupuncture therapies
(manual/laser acupuncture, electroacupuncture, body acupressure,
moxibustion and transcutaneous electrical nerve stimulation).

\emph{1.3 Data Extraction.}

Two investigators (H. Z. and YN.L.) independently extracted data from
each paper using predesigned form and reached consensus on all items;
disagreements were resolved by a third investigator (J.H.). We extracted
the following data from each selected study: authors, year of
publication, sample size, age, interventions and main outcomes.

\emph{1.4 Quality Assessment}

Two independent reviewers (Z.H. and YN.L.) assessed the risk of bias in
each study according to the risk of bias tool in the Cochrane Handbook
for Systematic Reviews of Interventions (version 5.1.0); discrepancies
were resolved by discussion with a third investigator (J.H.). Six
domains assessed for each included study were as follows: (1) random
sequence generation and allocation concealment; (2) blinding of
participants and personnel; (3) blinding of outcome assessors; (4)
incomplete outcome data; (5) selective reporting; (6) other bias.

\emph{1.5 Synthesis of Evidence}

We used the Reviewer Manager Software (version 5.3) for meta-analysis.
We analyzed dichotomous variables with risk ratio (RR); for continuous
variables, the mean difference (MD) was calculated with a 95\%
confidence interval (CI) and \emph{p} value. We did
\selectlanguage{greek}χ\selectlanguage{english}\textsuperscript{2}testing to assess the heterogeneities between
studies (\selectlanguage{greek}α\selectlanguage{english}=0.05), with a\emph{p} value\textless{}0.05 or\emph{I}
\textsuperscript{2}\textgreater{}50\% as being indicative of statistical
heterogeneity. When a heterogeneity was detected, a random effect model
was applied, and subgroup analysis was conducted to identify potential
sources of heterogeneity. If a \emph{p}value\textgreater{}0.05 or
\emph{I} \textsuperscript{2}\textless{}50\%, a fixed effect model was
conducted. Sensitivity analysis was conducted to test whether the
results were was robust by excluding the study one by one and comparing
the rest of the studies' effects with all the studies' total effects.
Funnel plots were generated if there were sufficient studies included in
the meta-analysis.

\textbf{2.Results}

\emph{2.1 Characteristics of Included Studies.}

We identified 332 potentially eligible articles. A total of 127
duplicates were excluded, and 150 unrelated records were also excluded
by reading their abstracts. After reading 55 full-text articles, 38
records were excluded for reasons such as not a RCT, insufficiency of
data and inconsistence of interventions or outcomes. Eventually, 17
RCTs\textsuperscript{{[}10-26{]}} were included in the systematic review
and 15 were included in the meta-
analysis\textsuperscript{{[}10-11},\textsuperscript{13-25{]}}, all of
which were published in Chinese. The study flow diagram is shown in
Figure 1.

In this meta-analysis, a total of 2574 parturient women were selected,
including 1288 cases in treatment groups and 1286 cases in control
groups. The controls of all selected trials received obstetric care
routine, such as psychological comfort and Doula delivery; the
intervention measures in treatment groups included auricular acupressure
(16 trials) and auricular acupuncture (1 trial). The main outcome
measures were WHO pain level (5 trials)
\textsuperscript{{[}15-16},\textsuperscript{19},
\textsuperscript{22-23{]}}, VAS score (4 trials)\textsuperscript{{[}10},
\textsuperscript{14},\textsuperscript{21}, \textsuperscript{24{]}} and
maternal satisfaction (3 trials)\textsuperscript{{[}10},
\textsuperscript{14},\textsuperscript{24{]}}; the secondary outcome
measures included duration of three stages of labour
(1\textsuperscript{st} 9 trials\textsuperscript{{[}10-11},
\textsuperscript{13-14},\textsuperscript{18-19},
\textsuperscript{21-24{]}}, 2\textsuperscript{nd} 6
trials\textsuperscript{{[}13},\textsuperscript{16},
\textsuperscript{19}, \textsuperscript{22-23},\textsuperscript{25{]}},
3\textsuperscript{rd} 4 trials\textsuperscript{{[}13},
\textsuperscript{19},\textsuperscript{22-23{]}}), postpartum blood loss
(2 trials)\textsuperscript{{[}15}, \textsuperscript{25{]}}, neonatal
Apgar score (4 trials)\textsuperscript{{[}10},
\textsuperscript{14},\textsuperscript{18}, \textsuperscript{24{]}},
number of spontaneous delivery cases (4
trials)\textsuperscript{{[}15-17},\textsuperscript{25{]}} and number of
caesarean section cases (3 trials)\textsuperscript{{[}15},
\textsuperscript{17},\textsuperscript{25{]}}. Table 1 shows the main
characteristics of the studies.

2.2 \emph{Methodological Quality of Included Studies.}

Out of all the 17 randomized controlled trials, only 6 of them reported
details about random sequence generation, 3 studies with a random number
table tool and 3 studies with date. No studies mentioned any details
related to allocation concealment. As for blinding, although 2 studies
claimed they were single-blind trials, since the materials and
manipulations used in the treatment were totally different in the test
and control groups, it's difficult to avoid performance bias. However,
at least the outcome assessors should have been blinded, the detection
bias of all studies was therefore classified as unclear. Most of the
articles showed a low risk of incomplete outcome bias and selective
reporting bias.

\emph{2.2 Meta-analysis.}

According to different phases of intervention and outcome measures, we
divided the 17 selected studies into 2 subgroups.

\emph{2.2.1 The first stage of labour}

\emph{2.2.1.1 VAS score in latent phase and active phase} Four studies
assessed the VAS score in the latent and active phase of labour. We
adopted a random effect model, because heterogeneity between the studies
was observed (\emph{p} \textless{}0.01; I\textsuperscript{2}=99\%,
96\%). Pooled analysis of the 4 studies showed that VAS score in
auricular acupressure groups was significantly lower than the controls
during latent phase (MD=-2.56, 95\%CI: {[}-4.26,0.86{]}, \emph{p}
=0.003). However, there were no significant differences in active phase
(Figure 4). Sensitivity analysis indicated that the results were robust.

\emph{2.2.1.2 Maternal satisfaction in latent phase} Three studies
reported maternal satisfaction in latent phase. There was no
between-study heterogeneity (I\selectlanguage{ngerman}²=0\%), so a fixed effect model was
conducted. The pooled analysis indicated that satisfaction rate in the
auricular acupressure groups was significantly higher than in the
control groups (RR=1.29, 95\%CI {[}1.18, 1.41{]},\emph{p}
\textless{}0.05) (Figure 5). Sensitivity analysis indicated that the
results were robust.

\emph{2.2.1.3 Duration of the first stage of labour} Pooled analysis of
the 6 studies that reported duration of the first stage of labour showed
a significant reduction in duration of the first stage when participants
were treated with auricular acupressure compared with the controls
(MD=-1.24, 95\%CI {[}-1.86, -0.61, \emph{p} \textless{}0.05{]}), with
significant between-study heterogeneity (I\textsuperscript{2}=97\%)
(Figure 6). Sensitivity analysis indicated that the results were robust.

\emph{2.2.1.4 Neonatal Apgar score} Four studies reported neonatal Apgar
score in both 1 minute and 5 minutes with significant heterogeneity
(I\textsuperscript{2}=87\%) and no heterogeneity
(I\textsuperscript{2}=0\%) respectively. We pooled studies and found no
significant difference between groups (Figure 7). Sensitivity analysis
indicated that Li et al.\textsuperscript{{[}18{]}} appeared to add
significant heterogeneity to 1 min Apgar score. Removing this study
eliminated this heterogeneity (I\textsuperscript{2}=0\%), and changed
the effect size of the pooled result (Z = 0.27, P = 0.79) , but there
was still no significant difference between groups.

\emph{2.2.2 All stages of labour}

\emph{2.2.2.1 Analysis of pain level} Five studies assessed incidence of
pain at 3 levels including \selectlanguage{english}I, \selectlanguage{english}II and \selectlanguage{english}III, in which pain at level \selectlanguage{english}III had the
greatest impact on participants. For meta-analysis, the incidence of
pain at level \selectlanguage{english}III was converted into a dichotomous variable. We pooled the
studies and found that auricular acupressure significantly reduced the
incidence of pain at level \selectlanguage{english}III compared to the controls (RR=0.17, 95\%CI
{[}0.13, 0.24{]}, \emph{p} \textless{}0.05), with no heterogeneity
(I\textsuperscript{2}=0\%) (Figure 8). Sensitivity analysis indicated
that the results were robust.

\emph{2.2.2.2 Duration of each stage of labour} Six studies investigated
duration of each stage of labour. Summary results showed a significant
reduction in duration of the first stage in the study groups compared to
the control groups (MD=-2.57, 95\%CI {[}-3.69, -1.45{]},\emph{p}
\textless{}0.05), with statistically significant heterogeneity
(I\textsuperscript{2}=81\%, 97\%, 99\%). Nevertheless, there were no
significant differences in the second and third stage of labour (Figure
9). Sensitivity analysis indicated that the results were robust.

\emph{2.2.2.3 Postpartum blood loss} Two trials reported postpartum
blood loss. Pooling the data of the studies showed no significant
difference between auricular acupressure intervention and obstetric care
routine, with significant heterogeneity (I\textsuperscript{2}=97\%)
(Figure 10). Sensitivity analysis indicated that the results were
robust.

\emph{2.2.2.4 Incidence of spontaneous delivery} Pooled analysis of four
studies that assessed incidence of spontaneous delivery showed no
significant difference between the study groups and the control groups
with significant heterogeneity (I\textsuperscript{2}=84\%) (Figure 11).
Sensitivity analysis indicated that Ye et
al.\textsuperscript{{[}25{]}}appeared to add to significant
heterogeneity. Removing this study eliminated this heterogeneity
(I\textsuperscript{2}=0\%), and changed the effect size of the pooled
result (Z = 2.89, P = 0.004), but the difference is still not
significant.

\emph{2.2.2.4 Incidence of caesarean section} Three studies reported
incidence of caesarean section. A fixed effect model was applied, for
there was no evidence of heterogeneity (I\textsuperscript{2}=0\%).
Summary results indicated a lower incidence of caesarean section in
auricular acupressure groups compared to the control groups (RR=0.36,
95\%CI {[}0.20, 0.65{]}, \emph{p} =0.0006) (Figure 12). Sensitivity
analysis indicated the results were robust.

\textbf{3. Discussion}

\emph{3.1 Main findings}

Meta-analysis showed that auricular acupressure was more effective for
latent analgesia in the first stage of labour, but not in the active
stage, which may be related to different severity of pain in the active
and latent stages of labour. However, the incidence of grade III pain
throughout labour was reduced in the auricular acupressure group,
suggesting that auricular acupressure is effective in relieving
breakthrough pain in labour. Since breakthrough pain after receiving
pain relief can increase patient's
dissatisfaction\textsuperscript{{[}27{]}}\selectlanguage{english},the maternal satisfaction
shown in the meta-analysis was improved.

For the duration of labour, the first stage of labour was shorter in the
auricular acupressure group, whereas the second and third stages of
labour were not significantly different, which may be associated with
the longer duration of the first stage of labour.

The safety of auricular acupressure is investigated through Apgar score,
delivery mode and postpartum hemorrhage. These outcomes did not show any
significant difference between auricular acupressure groups and the
controls.

3.2 \emph{Limitations}

First, only published Chinese and English articles were retrieved, which
may lead to publication bias due to incomplete literature collection.
Second, most included studies did not provide methodological details on
randomization, allocation concealment and blinding, which reduced the
reliability of the findings. Besides, although only one study used
auricular acupuncture, the stimulation of auricular acupressure and
auricular acupuncture is different, and the intensity of stimulation may
vary between studies due to the degree or frequency of pressure. The
significant heterogeneity of some outcomes may be attributable to this.
In addition, although labour pain is different between nulliparous and
multiparous women, the size of the fetus can also affect labour pain,
some studies failed to specify these factors.

3.3 \emph{Implication for clinical trial design}

As a subjective feeling, labour pain is highly complex, further
well-designed trials with high methodological quality should be
conducted, and careful trained clinicians and standardized intervention
protocols are needed to minimize the subjective effect. Besides, to
explore the differential analgesic effects among nulliparous and
multiparous women and the effect of fetus size on labour analgesia,
further studies as well as the manipulate methods (e.g. acupressure and
acupuncture) are needed.

4. Conclusion

According to our findings, auricular acupressure showed a pain-relieving
effect compared with the routine care. Although the evidence is limited
and high quality studies are needed, this review has lent a support for
the efficacy of auricular acupressure in the clinical management of
labour pain .

Disclosure of interest

The authors have no conflicts of interests to disclose.

Contribution to authorship

Jing Han, Hao Lv and Zhe Wang wrote the protocol. Zhe Wang performed the
search. Hao Zheng, Zhe Wang and Yanan Li independently selected eligible
studies and extracted data. Differences of opinion were registered and
resolved by consensus with Jing Han. Zhe Wang and Hao Zheng performed
the meta-analyses. Yanan Li, Hao Zheng and Zhe Wang participated in the
interpretation of the data and writing of the review

Details of ethics approval

Ethical approval was not needed for this meta-analysis

Funding

This study was supported by the Health Talents Project of Shandong
Province.

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21. Lu M. Effectiveness of auricular acupressure for latent labor
analgesia and accelerating labor. Chinese Baby 2016\textbf{:} 36.

22. Song C. Application of Auricular Point Taping and Pressing Therapy
in Doula Type Labor. CHINESE ACUPUNCTURE \& MOXIBUSTION
2002(08)\textbf{:} 18-19.

23. Tian Q, Ma Y, Ma Q, Ma J. 50 cases of labor analgesia with auricular
acupressure. CHINESE ACUPUNCTURE \& MOXIBUSTION 2006(03)\textbf{:} 212.

24. Wei Z, Jia J, Zhao G, Huang Z, Zhang J. Clinical research on
auricular acupoint plaster therapy applied in labor analgesia in latent
phase. Nursing and Rehabilitation Journal 2016, \textbf{15}
(08)\textbf{:} 732-734.

25. Ye L, Guo L, Tang W. Effects of vaginal birth analgesia using
auricular pressure beans on birth outcomes. Journal of Mathematical
Medicine 2016, \textbf{29} (01)\textbf{:} 106-107.

26. Zhao Y, Li Y, Wang J, Wang J, Zhang X. Application of auricular
acupressure on latent labor analgesia. KANGYI 2020\textbf{:} 255.

27. Akerman N, Dresner M. The management of breakthrough pain during
labour. CNS DRUGS 2009, \textbf{23} (8)\textbf{:} 669-679.\selectlanguage{english}
\begin{longtable}[]{@{}llllllllll@{}}
\toprule
Authors & Sample size & Sample size & Age & Age & Intervention &
Intervention & Intervention & Controls & Outcomes\tabularnewline
\midrule
\endhead
& T & C & T & C & Stage & Intervention measures & Auricular points &
&\tabularnewline
He 2020 & 50 & 50 & 33.5\selectlanguage{ngerman}±2.4 & 36.2\selectlanguage{ngerman}±8.5 & Latent phase & A &
TF\textsubscript{2}, AH\textsubscript{6a}, TF\textsubscript{5},
AH\textsubscript{9}, TF\textsubscript{4} & C & a, b, c, d,
g\tabularnewline
Li 2017 & 40 & 40 & 30.57\selectlanguage{ngerman}±2.14 & 31.04\selectlanguage{ngerman}±4.62 & Latent phase & A &
TF\textsubscript{4}, TF\textsubscript{2}, TF\textsubscript{5},
AH\textsubscript{6a}, AH\textsubscript{9} & C & c, g\tabularnewline
Wei 2016 & 100 & 100 & 27.0\selectlanguage{ngerman}±2.6 & 26.1\selectlanguage{ngerman}±2.9 & Latent phase & A &
AH\textsubscript{6a}, TF\textsubscript{2}, TF\textsubscript{5},
TF\textsubscript{4}, AH\textsubscript{9} & C & a, b, c, d,
g\tabularnewline
Lu 2016 & 50 & 50 & 26.32\selectlanguage{ngerman}±3.35 & 27.22\selectlanguage{ngerman}±3.09 & Latent phase & A &
AH\textsubscript{9}, TF\textsubscript{4}, TF\textsubscript{5},
TF\textsubscript{2}, AH\textsubscript{6a} & C & a, b, d\tabularnewline
Ding 2019 & 100 & 100 & 27.5\selectlanguage{ngerman}±3.1 & 27.5\selectlanguage{ngerman}±3.1 & Latent phase & A &
AH\textsubscript{9}, TF\textsubscript{4}, TF\textsubscript{5},
TF\textsubscript{2}, AH\textsubscript{6a} & C & d\tabularnewline
Liu2016 & 100 & 100 & 20-35 & 20-35 & First stage of labor & A &
CO\textsubscript{18}, TF\textsubscript{2}, AH\textsubscript{6a},
TF\textsubscript{4}, AT\textsubscript{4} & C & d\tabularnewline
Chen 2021 & 100 & 100 & 28.20\selectlanguage{ngerman}±3.38 & 28.41\selectlanguage{ngerman}±3.40 & Latent phase & A &
TF\textsubscript{2}, TF\textsubscript{4}, AT\textsubscript{4},
CO\textsubscript{18}, AH\textsubscript{6a}, AH\textsubscript{9} & C & a,
b, c, d, g\tabularnewline
Fu 2018 & 102 & 100 & 31.30\selectlanguage{ngerman}±8.70 & 31.30\selectlanguage{ngerman}±8.70 & Latent phase & A &
TF\textsubscript{2}, CO\textsubscript{10}, TF\textsubscript{4},
TG\textsubscript{2p}, CO\textsubscript{18}, AH\textsubscript{6a},
AT\textsubscript{4}, AT\textsubscript{3} & C & a\tabularnewline
Zhao 2020 & 34 & 34 & 31.20\selectlanguage{ngerman}±8.6 & 31.20\selectlanguage{ngerman}±8.6 & Latent phase & A &
TF\textsubscript{2}, CO\textsubscript{18}, AT\textsubscript{4},
AH\textsubscript{6a} & C & a\tabularnewline
\bottomrule
\end{longtable}

Table 1: Characteristics of included studies\selectlanguage{english}
\begin{longtable}[]{@{}lllllllllll@{}}
\toprule
Authors & Sample size & Sample size & Age & Age & Age & Intervention &
Intervention & Intervention & Controls & Outcomes\tabularnewline
\midrule
\endhead
& T & C & T & T & C & Stage & Intervention measures & Auricular points &
&\tabularnewline
Hu 2012 & 200 & 200 & 19\textasciitilde{}32 & 19\textasciitilde{}32 &
19\textasciitilde{}32 & Active phase-end of labor & A &
TF\textsubscript{2}, TF\textsubscript{4}, CO\textsubscript{18},
AH\textsubscript{6a} & C & e, h, j\tabularnewline
Song 2002 & 30 & 30 & 20\textasciitilde{}36 & 20\textasciitilde{}36 &
20\textasciitilde{}30 & All stages of labor & A & TF\textsubscript{2},
TF\textsubscript{4}, AH\textsubscript{8} & C & d, e, f, h,
i\tabularnewline
Tian 2006 & 50 & 50 & 22\textasciitilde{}31 & 22\textasciitilde{}31 &
22\textasciitilde{}31 & All stages of labor & A & TF\textsubscript{2},
CO\textsubscript{18}, AT\textsubscript{4} & C & d, e, f,
h,\tabularnewline
Liu 2017 & 92 & 92 & 26.51\selectlanguage{ngerman}±3.90 & 26.51\selectlanguage{ngerman}±3.90 & 26.51\selectlanguage{ngerman}±3.90 & All stages
of labor & A & AT\textsubscript{4}, CO\textsubscript{18},
TF\textsubscript{2} & C & d, e, f, h,\tabularnewline
Hu 2011 & 110 & 110 & 21\textasciitilde{}40 & 21\textasciitilde{}40 &
21\textasciitilde{}42 & All stages of labor & A & TF\textsubscript{2},
CO\textsubscript{18}, AT\textsubscript{4} & C & h, i, j,
k\tabularnewline
Ye 2016 & 50 & 50 & 18.8\selectlanguage{ngerman}±4.5 & 18.5\selectlanguage{ngerman}±4.6 & 18.5\selectlanguage{ngerman}±4.6 & All stages of labor
& A & CO\textsubscript{12}, TF\textsubscript{4}, CO\textsubscript{4},
CO\textsubscript{13} & C & e ,i, k, j, k\tabularnewline
Gao 2009 & 50 & 50 & 20\textasciitilde{}35 & 20\textasciitilde{}35 &
20\textasciitilde{}35 & All stages of labor & A & TF\textsubscript{2},
TF\textsubscript{4}, AH\textsubscript{6a}, AH\textsubscript{8} & C & d,
e, f\tabularnewline
Jiang 1997 & 30 & 30 & 26\selectlanguage{ngerman}±3.58 & 27\selectlanguage{ngerman}±3.65 & 27\selectlanguage{ngerman}±3.65 & All stages of labor
& B & TF\textsubscript{2}, TF\textsubscript{4}, CO\textsubscript{14},
AT\textsubscript{4} & C & j, k\tabularnewline
\bottomrule
\end{longtable}

Table 1: Characteristics of included studies

A, auricular acupressure B, auricular acupuncture C, blank control or
care routine

a, VAS score during latent phase of the first stage of labor

b, VAS score during active phase of the first stage of labor

c, maternal satisfaction

d, duration of the first stage of labor

e, duration of the second stage of labor

f, duration of the third stage of labor

g, neonatal Apgar score

h, WHO pain levels

i, postpartum blood loss

j, number of spontaneous delivery cases

k, number of caesarean section cases\selectlanguage{english}
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