Labor pain, a pivotal aspect of pregnancy, brings about significant physiological, psychological, and emotional repercussions for women, impacting both maternal and fetal health [1]. Diverse complications, such as stillbirth, preeclampsia, gestational diabetes, and anxiety, contribute to the varying intensity of labor pain experienced by pregnant women globally [2]. Recent research indicates that acupuncture serves as an effective strategy for managing pain during labor [3]. Given the role of the sympathetic nervous system in amplifying labor pain, interventions aimed at alleviating discomfort are crucial, as they may impact labor progression and delivery outcomes [4].

Previous studies have demonstrated acupuncture’s potential to shorten labor duration and provide substantial pain relief, highlighting its value as a supportive tool for healthcare professionals [5-8]. The critical nature of pain management in labor is underscored by the potential side effects associated with traditional pain medications [9]. Consequently, there is a growing preference for alternative and complementary therapies among both healthcare providers and expectant mothers.

Complementary and integrative medicine offers a spectrum of strategies for labor analgesia, with practices such as massage, aromatherapy, breathing, relaxation, acupuncture, acupressure, cupping therapy, auriculotherapy, reflexology, mind–body medicine, and yoga gaining prominence [10-13]. Despite the proven efficacy of auriculotherapy—a form of ear acupuncture and acupressure—in pain management, its specific application in alleviating labor pain has not been comprehensively and systematically evaluated.

This systematic review and meta-analysis aimed to address this gap by rigorously assessing the efficacy of auriculotherapy in reducing labor pain. By synthesizing existing evidence, we sought to provide valuable insights into the potential role of auriculotherapy as a viable and effective method of pain management during labor.

This systematic review and meta-analysis was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

1. Search strategy

The electronic databases PubMed, Scopus, and Cochrane Library were systematically searched from inception to May 2023 for randomized controlled trials (RCTs) investigating auriculotherapy as a pain management intervention during labor. The search syntax included the following keywords coupled with Boolean operators: (“auriculotherapy” OR “ear acupuncture” OR “ear acupressure”) AND (“childbirth” OR “delivery” OR “labor pain”). The search was further limited to articles published only in the English language. Following predefined inclusion and exclusion criteria, three authors (VA, AB, and MK) independently conducted title and abstract screening to identify potentially eligible studies. Additionally, the reference lists of all eligible studies and relevant systematic reviews were scrutinized for any additional articles that may have been missed in the electronic database search.

1. Inclusion criteria

This systematic review included RCTs involving healthy pregnant women of any age, including nulliparous, primiparous, and multiparous individuals, with gestational ages ranging from 36 to 42 weeks. The interventions consisted of either ear acupuncture or ear acupressure, with or without standard care. There were no restrictions on the type of comparator groups, which could have received either placebo at a specific point or any usual care and conventional treatment for managing labor pain. The primary outcome was pain intensity reported by women during labor, measured using a linear visual analog scale (VAS).

2. Exclusion criteria

Studies involving patients with severe preeclampsia, placenta previa, or other pregnancy-related complications (e.g., gestational diabetes, polyhydramnios, or oligohydramnios), as well as those with mental illnesses, were excluded from the review. We also excluded nonrandomized trials, case reports, studies with alternative designs, and articles not written in English. Additionally, studies were excluded if they involved non-ear points, moxibustion, cupping, acupoint transcutaneous electrical nerve stimulation, or auricular seed therapy.

3. Data extraction and reliability

Two independent authors (VV and GA) used a predesigned form to extract the following data from the eligible studies: first author’s name, publication year, country of origin, participant age range, sample size, study design, intervention details, measured outcome parameters, and reported results. The extracted data were then reviewed by two additional authors (STV and MK). Any discrepancies encountered during the extraction process were resolved through discussion with the corresponding author.

4. Quality assessment of included studies

Two independent reviewers (PS and PN) used the Cochrane risk-of-bias tool to assess the quality of the included RCTs across various domains of bias, including random sequence generation, allocation concealment, participant and personnel blinding, outcome assessment blinding, incomplete outcome data, selective reporting, and so forth. Each domain was judged as low, high, or unclear risk of bias according to predefined criteria.

5. Statistical analysis

This meta-analysis was conducted using the meta and metafor packages of R software (version 4.0.2). The weighted mean difference (MD) and 95% confidence interval (CI) of posttreatment VAS pain intensity scores were calculated to compare the experimental and control groups. The I2 statistic and Cochran Q test were used to assess heterogeneity among the included studies. Additionally, to account for potential variability among the RCTs and therefore enhance the accuracy of our results, we employed a random-effects model.

1. Literature selection

The literature selection process was performed by three independent authors (AB, MK, and VA). Initially, database searches with keywords related to auriculotherapy for labor pain management yielded a total of 209 potentially relevant articles, which were reduced to 138 articles for screening after duplicates were removed. Of these, 76 were excluded as they were abstract-only articles, incomplete or unpublished articles, or articles published in languages other than English. Finally, a thorough full-text review of the remaining articles led to the selection of five eligible studies for inclusion in the meta-analysis (Fig. 1).

Figure 1. PRISMA search and flow chart for this meta-analysis.

2. Literature characteristics

Table 1 summarizes the five studies included in our meta-analysis, all conducted between 2008 and 2023. The geographical distribution of these English-language RCTs was as follows: three in Iran [14-16], one in Denmark [17], and one in Brazil [18].

Table 1

General characteristics of the included studies in this meta-analysis.

Author	Country	Age	Gravidity	Gestational age	Study design	Sample size	Intervention details for experimental group	Intervention details for control group	Duration	Frequency	Result
Abedi et al., 2017	Iran	18-35	Nulliparous	37-40 weeks	RCT	T = 80 E = 40 C = 40	Auriculotherapy	Standard care		3 times (4,6,8 cm of cervical dilation)	Auriculotherapy has significantly reduce labour pain
Alimoradi et al., 2020	Iran	19-35		37-42 weeks	RCT	T = 90 E = 30 BA = 30 C = 30	Ear acupressure	Standard care	30 seconds	For every 30 minutes	Ear acupressure was significantly effective in reducing labor pain
Kindberg et al., 2009	Denmark	26.4	Primiparous	36 weeks	RCT	T = 207 E = 105 C = 102	Ear acupuncture	Local anaesthetics	Few min		Auriculotherapy was less effective for pain relief compared to local anaesthetic
Mafetoni and Shimo, 2016	Brazil	Any age	Nulliparous & Multiparous	36 weeks	RCT	T = 30 E = 10 P = 10 C = 10	Ear acupressure	B = Placebo, C = Control group	Pressure for a min	1 times	The auriculotherapy group reported reduced labor pain and a shorter duration of labor
Valiani et al., 2018	Iran	18-35	Primiparous	37-41 weeks	RCT	T = 84 E = 42 C = 42	Acupressure	Usual Care	6 min	2 times	Auriculotherapy reduces the severity of labor pain in primiparous women

Four studies included participants aged 18 years and above [14-17], while one study had no age restrictions [18]. Sample sizes varied considerably, from 30 participants in the smallest study [18] to 207 in the largest one [17].

With respect to parity, three studies focused exclusively primiparous/nulliparous women [14,16,17], one included both nulliparous and multiparous women [18], and one did not specify participant parity [15]. Across all studies, participants’ gestational ages ranged from 36 to 42 weeks.

The study designs included three two-arm trials [14,16,17] and two three-arm trials [15,18]. Four studies reported the intervention duration [15-18], while one did not provide this information [14]. Similarly, four studies specified the intervention frequency [14-16,18], whereas one did not [17].

3. Risk of bias in included studies

Two review authors (GA and PS) independently used Covidence’s Cochrane risk-of-bias tool to assess the methodological quality of the included studies, as depicted in Fig. 2 and 3. All the studies demonstrated adequate random sequence generation, earning a low-risk rating in this domain [14-18]. Allocation concealment varied across the studies: three were deemed low-risk [14,15,18], one unclear [17], and one high-risk [16]. Regarding participant blinding, four studies received a low-risk rating [14,15,17,18], while one study was at high risk for bias [16]. Furthermore, outcome assessment blinding was considered at low risk of bias in three studies [14,15,18] but at high risk in two [16,17]. Four studies were categorized as low-risk for incomplete outcome data [14,15,17,18], whereas one study was rated as high-risk [16]. Selective outcome reporting was less clear across the studies, with four receiving unclear ratings [14-16,18] and one judged as high-risk [17]. Finally, in terms of other sources of bias, three studies were assessed as low-risk [14,15,18] and two as high-risk [16,17].

Figure 2. Risk of bias graph.

Figure 3. Risk of bias summary.

4. Meta-analysis

In total, five RCTs [14-18] involving 451 patients were included in this meta-analysis. The pooled estimate of effect size revealed a significant improvement in VAS scores following auriculotherapy for labor pain (MD, –1.78; 95% CI, –2.62 to –0.93). A random-effects model was utilized owing to significant heterogeneity among the included studies (I2, 87%; p < 0.01) (Fig. 4).

Figure 4. Effect of auriculotherapy on VAS compared with compared group.

The findings of this meta-analysis provide robust evidence supporting the use of auriculotherapy for labor pain reduction. The pooled estimate of effect size demonstrated a statistically significant improvement in VAS scores among women undergoing auriculotherapy. To address the substantial heterogeneity observed among the included studies, we employed a random-effects model, which helped account for interstudy variability. This research is noteworthy as it is the first to systematically evaluate and analyze the efficacy of auriculotherapy in reducing labor pain. While previous studies have shown potential benefits of auriculotherapy for pain management, this meta-analysis offers a comprehensive and reliable assessment of the available evidence on labor pain relief following auriculotherapy [19].

Recent systematic reviews and meta-analyses have demonstrated complementary practices, such as antenatal yoga, perineal massage, acupressure, and acupuncture, to be effective in reducing labor pain and improving the birthing experience of women [20,21]. Acupressure has been associated with shorter labor duration and decreased use of pain medication [22]. Similarly, acupuncture has been found to reduce both the intensity of labor pain and the need for pharmacological pain management during childbirth [23,24]. Both therapies have been deemed safe and effective, offering women additional options for pain relief and enhancing their overall birthing experience. They have also been shown to alleviate other pregnancy-related symptoms, such as nausea, vomiting, back pain, and anxiety, which suggests a more comprehensive impact on the overall well-being of pregnant women [15,25-27]. Specifically, acupuncture is known to promote relaxation and alleviate stress, which can be especially beneficial during labor and delivery [24]. The collective body of evidence supports the use of acupuncture as a valuable tool for enhancing women’s childbirth experience and promoting their physical and emotional well-being.

The present meta-analysis demonstrated the efficacy of auriculotherapy in reducing labor pain, with participants receiving auriculotherapy exhibiting significantly lower pain scores compared with the controls. This indicates that auriculotherapy can be incorporated into standard protocols for intrapartum pain management as a noninvasive and drug-free alternative for women seeking pain relief. Furthermore, the efficacy of auriculotherapy was found to be consistent across various types of labor pain, such as uterine contractions and back pain [20,28]. The benefits persisted even after treatment cessation, highlighting long-lasting effects of auriculotherapy [29]. Overall, these findings support the integration of auriculotherapy into obstetric care as a safe and effective option for women who prefer non-pharmacological interventions during labor.

1. Limitation

The current study had a number of limitations. Firstly, there was a lack of consistent reporting of auriculotherapy duration and frequency across the included studies. Secondly, insufficient information on the methods of random sequence generation, allocation concealment, and blinding reduced the methodological quality of these studies. Finally, this study was further limited by gestational age variability, small sample sizes, subjective measures of pain, and differences in participants’ parity.

In conclusion, this systematic review and meta-analysis suggests that auriculotherapy could be a beneficial intervention for pain management during labor. However, more rigorously designed RCTs with larger sample sizes are warranted to substantiate these findings. Furthermore, future research should investigate the long-term effects of auriculotherapy on both maternal and neonatal outcomes, as well as its efficacy across diverse cultural and socioeconomic settings. Despite these considerations, the potential of auriculotherapy to alleviate childbirth pain underscore its promise for further exploration and possible integration into clinical care protocols.

Conceptualization: MK, VA; Data curation: VA, AB; Investigation: MK, AB; Methodology: VA, VV; Software: MK, PS; Supervision: STV, GA, PN; Validation: MK, PS; Visualization: VV, MK; Writing: MK, VV, VA, AB.

The authors declare no conflict of interest.