Unveiling the latest evidence: an updated systematic review and meta-analysis and GRADE assessment on the effectiveness of acupressure in managing labor pain

Abstract

Background

Labor pain is a significant challenge during childbirth, highlighting the necessity for effective pain management strategies. Acupressure has been recognized as a non-pharmacological method; however, its efficacy requires comprehensive evaluation. This updated systematic review and meta-analysis seeks to consolidate the most recent evidence regarding the effectiveness of Acupressure in alleviating labor pain and to evaluate the quality of this evidence using the GRADE framework.

Methods

An updated systematic review was conducted by querying multiple databases for randomized controlled trials (RCTs) that evaluated the impact of Acupressure on labor pain. Studies were included based on predefined eligibility criteria. The risk of bias was assessed using the Cochrane risk-of-bias method for randomized trials (RoB). Meta-analyses were performed to determine the overall effect size, and the GRADE approach was applied to assess the certainty of the evidence. Meta-analyses of all the data were done using RevMan 5.4.

Results

A total of 37 studies met the inclusion criteria. The meta-analysis revealed that Acupressure significantly reduces labor pain compared to touch (MD = -1.19, 95% CI -1.66 to -0.72, p < 0.00001), Sham (MD = -1.41, 95% CI -2.55 to -0.27, p = 0.01), and no intervention group (MD = -2.32, 95% CI -2.87 to -1.76, p < 0.00001). Although both SP6 and LI4 Acupressure points reduced pain, SP6 had more of an impact compared to previous reviews. The funnel plot comparing the effect of Acupressure with a touch on labor pain intensity suggested a possible publication bias. The GRADE assessment indicated a moderate to low level of certainty regarding these results.

Conclusions

Acupressure seems to be a viable method for alleviating labor pain, supported by moderate to low-quality evidence. Additionally, it is advisable to conduct well-designed RCTs to enhance the validity of these findings and investigate the underlying mechanisms that contribute to the effectiveness of Acupressure in this setting.

Background

Labor pain management remains a critical aspect of obstetric care, significantly impacting maternal experiences and birth outcomes [1]. Among various non-pharmacological interventions, Acupressure has garnered attention for its potential to alleviate labor pain without the side effects associated with pharmacological methods [2]. Acupressure, a key component of traditional Chinese medicine, involves applying physical pressure to specific points on the body, known as acupoints, to balance the body's energy flow and promote healing. This technique is hypothesized to stimulate the release of endorphins, the body's natural painkillers, and block pain pathways, thereby reducing the perception of pain during labor [3, 4].

Despite the growing body of research on Acupressure for labor pain, findings have been inconsistent. Numerous meta-analyses and systematic reviews have validated the significant reduction in labor pain achieved through Acupressure, which also enhances maternal satisfaction [5,6,7,8]. Specifically, Acupressure at points such as SP6 and LI4, as well as auricular Acupressure, has demonstrated notable pain relief during labor [9,10,11]. Furthermore, the combination of Acupressure with birthing ball exercises is particularly effective in mitigating labor pain [12]. In contrast, Some studies suggest that the evidence supporting Acupressure's role in decreasing labor pain is limited and inconsistent [13, 14].

Tanjung et.al highlighted that many studies suffer from methodological flaws such as small sample sizes and lack of blinding, making it difficult to draw definitive conclusions [11]. However, Smith highlighted the variability in Acupressure techniques and acupoints used, which could affect the generalizability of their findings [15], further emphasize the insufficient evidence to support Acupressure's widespread use, calling for more robust and well-designed clinical trials [16]. Xu et al. (2022) also evaluated existing evidence and concluded that the effectiveness of Acupressure for labor pain is not well-supported by high-quality research [17], recommending alternative pain management strategies until more conclusive evidence is available. In contrast, Chen et al. (2019) reported significant pain relief and reduced need for pharmacological analgesia with Acupressure but pointed out substantial heterogeneity among studies and potential publication bias [6]. Similarly, Karimi et al. (2020) reported that although Acupressure positively impacted labor pain, the quality of the included studies was generally moderate. They recommended that further high-quality research is necessary to confirm the effectiveness of Acupressure [5]. A review of the existing literature indicates that although certain studies have demonstrated considerable pain alleviation through Acupressure, others have identified methodological shortcomings, including limited sample sizes, absence of blinding, and discrepancies in Acupressure techniques. These variations and inconsistencies underscore the necessity for a comprehensive systematic review to consolidate the available evidence and offer a more precise understanding of the efficacy of Acupressure in managing labor pain. This updated systematic review and meta-analysis, supplemented by a Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach, aims to comprehensively and rigorously evaluate the current literature. The GRADE framework was chosen because of its ability to systematically assess the quality of evidence, considering factors such as risk of bias, inconsistency, indirectness, imprecision, and publication bias. This approach allows for a transparent and rigorous assessment of the evidence, which is particularly important given the heterogeneity observed in the existing literature on Acupressure for labor pain. By assessing the quality of evidence and the strength of recommendations, this study seeks to inform clinical practice and guide future research in this field. The findings are expected to contribute to the broader understanding of non-pharmacological pain relief methods and their application in obstetric care.

Methods

Study design

This systematic review and meta-analysis followed the recommended guidelines in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement [18]. Adhering to the PRISMA guidelines enhances the credibility and trustworthiness of the study's results by providing a standardized approach to conducting and reporting systematic reviews and meta-analyses.

Information sources

The search strategy ensured thoroughness in sourcing relevant studies. PubMed, Cochrane Library, Web of Science, Scopus, Cinahl, and Embase were scrutinized from their inception up to 13/01/2025. Furthermore, grey literature, conference abstracts, and the reference lists of selected studies were meticulously explored to augment the breadth of the review.

Search strategy

The search terms included a combination of keywords related to Acupressure, acupoint, childbirth, labor pain, and pain relief. The search strategy was tailored to each database and was conducted by two independent reviewers (see Appendix 1).

Criteria for study selection

Types of studies

Only randomized controlled trials (RCTs) were included. Studies reported in abstract form were considered if sufficient information was available to assess bias risk. Cluster trials were eligible, but none were found. Studies were excluded if they were Cross-over trials and quasi-randomized trials, involved mixed interventions, lacked adequate data, or had irrelevant control groups. This exclusion criteria ensured that only high-quality, relevant studies were included, although it may have limited the breadth of the review by excluding studies with different designs or methodologies.

Types of participants

Women who were laboring spontaneously or inducedly, regardless of parity and gestation status, were included. Both singleton and multiple pregnancies were included.

Types of interventions

Any type of Acupressure compared to sham, touch, no treatment, or routine care.

Outcome measures

Our outcome of interest was the intensity of labor pain, measured by any scale. Specifically, we aimed to assess the effectiveness of Acupressure in reducing labor pain intensity compared to standard care or placebo interventions.

Data extraction

First, a data extraction form was created. Two reviewers independently extracted data from eligible studies. Disagreements were resolved through discussion or consultation with a third reviewer. Data were then entered into Review Manager software (RevMan 5.4) and their accuracy was verified. In instances where data were either missing or ambiguous, we made efforts to reach out to the lead authors for further clarification. If we did not receive a response, the study was excluded from the meta-analysis to prevent the introduction of bias through imputation techniques.

Bias assessment

We evaluated the risk of bias in the included randomized controlled trials (RCTs) using the Cochrane Risk of Bias (RoB) tool [19]. This tool encompasses five key domains of bias that are critical for assessing the validity of the studies:

• 1. Selection Bias: This domain examines the random sequence generation and allocation concealment to ensure participants were assigned to interventions in a manner that minimizes selection bias.

• 2. Performance Bias: This involves evaluating the blinding of participants and study personnel during the trial to reduce the impact of biases related to their expectations and behaviors.

• 3. Detection Bias: Assessed by determining whether outcome assessors were blinded to the intervention status, thereby ensuring that the assessment of outcomes was not influenced by knowledge of the assigned groups.

• 4. Attrition Bias: This domain is concerned with the completeness of outcome data, analyzing the extent and reasons for participant dropouts or exclusions during the study.

• 5. Reporting Bias: This involves evaluating whether the outcomes reported were consistent with those originally proposed, to identify any selective reporting that may distort the findings.

Each domain was rated as having a low, high, or unclear risk of bias. Two reviewers independently assessed the risk of bias for each study, and any disagreements were resolved through discussion or by consulting a third reviewer. The bias assessment results were used to inform the interpretation of the meta-analysis findings and to conduct sensitivity analyses and Grade assessment.

Measures of treatment effect

In the included RCTs, various scales were employed to assess labor pain intensity, including the Visual Analog Scale (VAS), the McGill Pain Questionnaire (MPQ), and the Numeric Rating Scale (NRS). To measure the treatment effect, we calculated the mean differences (MD) between groups, because the scales, once transformed to a common 0–10 range, allowed for direct comparison without the need for standardization. Notably, the study that used the McGill Pain Questionnaire also utilized the VAS, which we considered in the analysis.

Assessment of heterogeneity

To assess heterogeneity among included RCTs, we used the following methods:

• 1. Visual inspection of forest plots: We visually inspected forest plots to identify any obvious differences in the direction and magnitude of effects across studies.

• 2. Statistical tests:

  • ◦ Chi-square test (Q test): We used the Chi2 test to assess whether observed differences in results were consistent with chance alone. A p-value of less than 0.10 was considered to indicate significant heterogeneity.

  • ◦ I-squared statistic (I²): We calculated the I² statistic to quantify the percentage of total variation across studies that was due to heterogeneity and not chance. Values ​​of 25%, 50%, and 75% were considered low, moderate, and high heterogeneity, respectively.

• 3. Subgroup analysis: We also performed subgroup analyses to examine how different subgroups within studies contributed to the overall heterogeneity. Subgroup analyses were conducted based on the specific points used (e.g., SP6 and LI4), the number of points targeted (single-point vs. multiple-point Acupressure), and the type of control groups (e.g., touch, smell, no intervention). These variables were selected to explore potential sources of heterogeneity and assess whether different Acupressure techniques or protocols influenced the results.

• 4. Sensitivity Analyses: (see sensitivity analysis).

These methods allowed us to thoroughly assess and address heterogeneity, ensuring the robustness and reliability of our meta-analysis findings.

Assessment of reporting bias

For meta-analyses that included 10 or more studies, we employed funnel plots to visually inspect for asymmetry. The presence of asymmetry in funnel plots may indicate publication bias—i.e., the possibility that studies with negative or unexpected results are less likely to be published.

Data synthesis

Statistical analyses were performed using RevMan 5.4. A fixed-effects model was initially contemplated for the analysis, based on the assumption that all studies exhibit a uniform effect size. Nevertheless, due to the considerable heterogeneity identified among the studies included, a random-effects model was ultimately selected as the more suitable option. This model effectively addresses the variability in treatment effects that may result from differences in study populations, settings, and methodologies, thereby offering a more precise and adaptable analysis of the data. For random-effects analyses, results were presented as the average treatment effect with 95% confidence intervals and estimates of Chi2 and I2.

Sensitivity analysis

To ensure the robustness of our meta-analysis results, we conducted sensitivity analyses by:

• 1. Assessing the impact of including or excluding RCTs based on different quality thresholds.

• 2. Comparing results from fixed-effect and random-effects models to evaluate the consistency of the findings.

• 3. Conducting leave-one-out analyses to identify any single study that disproportionately affects the overall results.

• 4. Excluding studies with extreme effect sizes to assess their impact on the overall results

Assessment of Certainty of Evidence Using the GRADE Approach

The certainty of the evidence was assessed using the GRADE approach, as outlined in the GRADE Handbook [20]. This method was applied to evaluate the body of evidence for the primary comparisons: Acupressure vs. sham control, Acupressure vs. usual care, and Acupressure vs. touch control.

The GRADE framework was selected due to its ability to offer a structured and transparent method for evaluating the quality of evidence. This framework enables us to determine our level of confidence in the findings by taking into account several essential factors. It is especially beneficial when integrating evidence from studies that employ varying methodologies or possess differing levels of quality, as it promotes a fair and trustworthy analysis of the data. The GRADE approach assesses the certainty of evidence for each outcome by considering five critical factors:

• 1. Study limitations: This factor refers to the risk of bias in studies, assessing potential flaws that could affect the validity of the results.

• 2. Consistency of effect: Considers the extent to which results are similar across studies, which indicates reliability.

• 3. Imprecision: This relates to the precision of the effect estimate, which includes confidence intervals and sample size of studies.

• 4. Indirectness: This assesses the applicability of the evidence to a specific research question and assesses whether the populations and interventions studied are relevant to the context in which the findings are applied.

• 5. Publication bias: This addresses the potential for selective publication of studies, which can skew the overall evidence if certain results are more likely to be published than others.

By analyzing these domains, the GRADE approach provides a comprehensive framework for determining the overall certainty of evidence related to specific outcomes. The evidence was downgraded to one level for serious risk of bias, inconsistency, indirectness, or imprecision and to two levels for very serious concerns in these areas. Publication bias was also considered, and evidence was reduced if the asymmetry of the funnel plot suggested potential bias.

Ethical considerations

We attempted to observe all scientific ethics requirements in this investigation. Since we conducted the research using public databases, we did not require approval from the ethics committee. The authors avoid plagiarism and data manipulation for personal advantage. As part of our commitment to transparency and reproducibility, we provided our raw data, processing details, and review technique overview.

Results

Search results

Figure 1 displays the PRISMA 2020 flow chart for systematic reviews. Initially, 696 primary articles were retrieved from databases. After removing duplicates, 408 articles proceeded to the first screening phase. Articles that seemed relevant based on the abstract and title were kept at this stage, while others were excluded. Subsequently, 139 articles underwent the second screening phase. Ultimately, following a thorough review of the full text of articles, 37 were included in the systematic review, and 33 were included in the meta-analysis.

Fig. 1

PRISMA 2020 flow diagram for systematic reviews

Included RCTs

Table 1 shows the characteristics of included RCTs. All RCTs featured a parallel design, with 14 RCTs being two-armed [2, 21,22,23,24,25,26,27,28,29,30,31,32,33], 21 RCTs being three-armed [29, 34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53], and 2 having four arms [54, 55]. Acupressure intervention was implemented in nearly all studies during the active phase of labor. The total sample sizes ranged from 30 [45] to 241 [54] across the included studies. The included trials were published between 2003 [39] and 2024 [47]. Among these, 21 studies were conducted in Iran [25,26,27, 30, 31, 34,35,36,37, 40,41,42, 44, 46, 48,49,50,51,52,53, 56], five in Turkey [22,23,24, 29, 55], two in Brazil [43, 45], Egypt [21, 28], and India [33, 38] and one in Taiwan [39], Korea [2], Cyprus [47], Indonesia [32], and China [54]. The majority of participants were low-risk pregnant women with an average age ranging from 20 to 30 years. No analyses were conducted to compare pain levels among different age groups in the studies reviewed. Most studies included women in their first or second pregnancy, with gestational ages between 37 and 42 weeks. However, few studies provided detailed information on parity, which may have influenced the results.

Table 1 Characteristics of included RCTs

Interventions and comparisons

In 9 RCTs, Acupressure was compared with touch [2, 24,25,26,27,28,29, 41, 49], 11 studies compared Acupressure with standard care [21,22,23, 32,33,34, 39, 42, 47, 54, 55], and 3 studies compared it with a Sham treatment [30, 31, 36]. 7 trials compared Acupressure with touch and standard care [37, 38, 43,44,45,46, 53], while one study compared Acupressure with Sham and routine measures [56]. Within 6 trials, two types of Acupressure were compared with touch [50], Sham [40], or standard care practices [35, 48, 51, 52] (Table 1).

Risk of bias

Table 2 and Fig. 2 show the risk of bias in studies individually and across domains within all included studies. Overall, none of the included studies were classified as having a low risk of bias across all domains. The domain of random sequence generation was assessed as low risk in 75% of studies (28 studies). 11 trials utilized block randomization [22, 25, 27, 29, 31, 34,35,36, 43, 46, 52], 5 studies employed computer-generated randomization [38, 40, 44, 51, 56], 6 studies used lot drawing [37, 41, 47, 49, 50, 55], two studies used the lottery method [23, 33], one used systematic randomization [42], two used a table of random numbers [2, 32], and one study utilized a coin toss [39]. In 32% of RCTs (n=12), the concealment of randomization was rated as low risk when sealed envelopes were used. Among all domains, the domain related to blinding of participants and personnel regarding risk was most prone to bias, with 62% of studies [23 trials] at risk of performance bias. 30% of RCTs (n=11) were at high risk of detection bias due to the lack of blinding of outcome assessment. 57% of studies (n=21) were judged to be at low risk of attrition bias. 73 % of studies were assessed as having an unclear risk of bias regarding selective reporting due to the absence of their protocols.

Table 2. Risk of bias judgment for included studies

Fig. 2

A visual representation of the risk of bias regarding each methodological quality domain, displayed across all included studies

Meta-analysis findings

Thirty-three trials had enough information to perform a meta-analysis. The findings of the meta-analysis in three parts of the effect of Acupressure versus touch, Sham, and no intervention are presented as follows.

1-Effect of Acupressure versus touch

1-1. Common effect size

Figure 3 shows the forest plot of the pooled MD of the effect of Acupressure versus touch on the labor pain intensity. A random-effects meta-analysis of 15 studies including 1401 participants showed a statistically significant effect of Acupressure compared to touch on labor pain intensity (MD = −1.19, 95% CI −1.66 to −0.72, p < 0.00001). There was significant heterogeneity across studies (Chi² = 114.81, I² = 88%, p < 0.00001). This result indicates that Acupressure was associated with a reduction in labor pain intensity compared to touch.

Fig. 3

Forest plot of the pooled MD of the effect of Acupressure versus touch on the labor pain intensity

1–2. Sub-groups analysis

All included studies utilized a single acupoint for Acupressure. Subgroup analyses were conducted based on the specific acupoints used: SP6 and LI4. Both the SP6 Acupressure (MD = −0.69, 95% CI: −1.00 to −0.37, p < 0.0001) and LI4 Acupressure (MD = −1.87, 95% CI: −2.73 to −1.00, p < 0.0001) demonstrated statistically significant effects in reducing labor pain. Despite heterogeneity, a random-effects model was employed due to the variability observed across studies.

1–3. Sensitivity analysis

In our sensitivity analysis, we explored various factors, including the exclusion of studies, different statistical models, and weighting strategies. However, the findings remained consistent.

1–4. Publication Bias

Figure 4 shows the funnel plot of the effect of Acupressure versus touch on the labor pain intensity. The funnel plot revealed potential publication bias in the included studies, as evidenced by its asymmetry. Smaller studies with significant results favoring Acupressure, particularly SP6, were more prevalent, while studies with neutral or negative findings were underrepresented. Larger studies tended to cluster near the MD line, suggesting more reliable and less variable outcomes. The heterogeneity observed may be attributed to differences in study protocols, Acupressure techniques, and population characteristics. This highlights the need for more robust, large-scale studies with standardized methodologies to reduce bias and provide more conclusive evidence on the efficacy of Acupressure for labor pain relief.

Fig. 4

Funnel plot of the effect of Acupressure versus touch on the labor pain intensity

2-Effect of Acupressure versus Sham

2-1. Common effect size

Figure 5 shows the forest plot of the pooled MD of the effect of Acupressure versus Sham on the labor pain intensity. The plot indicated a significant effect favoring Acupressure over Sham treatment (MD = −1.41, 95% CI −2.55 to −0.27, p = 0.01). These findings suggest that Acupressure may have a more pronounced effect than sham treatment, according to the data compiled from the included studies. The high heterogeneity (Chi² = 129.70, I² = 97%, p<0.00001) indicates variability in the study results, which is an important consideration when interpreting the data.

Fig. 5

Forest plot of the pooled MD of the effect of Acupressure versus Sham on the labor pain intensity

2-2. Sub-groups analysis

In our analysis, some studies utilized a single acupoint for Acupressure, while others simultaneously applied pressure to dual acupoints. We conducted a subgroup analysis based on these approaches. In summary, both single-point and dual-point Acupressure sub-groups demonstrated meaningful pain reduction during labor, but the reduction was statistically significant in the single-point approach (MD = −1.33, 95% CI −2.06 to −0.61, p = 0.0003).

2–3. Sensitivity analysis

Our sensitivity analysis revealed intriguing insights into the robustness of these findings. When we conducted the sensitivity analysis by systematically removing individual studies from the analysis, we found that the results became non-significant with the exclusion of all studies except for Sayyedzadeh Aghdam’s study [30]. This suggests that the overall effect observed in the Acupressure group may be heavily influenced by the results of specific studies. Conversely, when only Study of Sayyedzadeh Aghdam et al. was excluded from the analysis, the results became more statistically significant. This indicates that the mentioned study may have had a considerable impact on the overall findings, and its presence in the analysis could be masking the true effect of Acupressure on pain relief during labor. These findings emphasize the need for a cautious interpretation of the Acupressure's effect on labor pain, as the removal of certain studies alters the statistical significance of the results. This highlights the importance of the quality and reliability of individual studies in meta-analytic assessments. Further investigation and more robust studies are necessary to confirm the efficacy of Acupressure in this context.

3-Effect of Acupressure versus no intervention

3-1. Common effect size

Figure 6 shows the forest plot of the pooled MD of the effect of Acupressure versus no intervention on labor pain intensity. 25 RCTs of 1969 women were included in the meta-analysis. The majority of studies favor Acupressure, indicating its potential effectiveness in pain reduction. Based on a random effects model, the overall test statistics show a significant effect of Acupressure on pain relief during labor, with a Z-value of 8.18 and p < 0.00001. The pooled MD was −2.32, with a 95% CI of −2.87 to −1.76, suggesting a moderate to large effect size. There was considerable heterogeneity among the studies (Chi² = 686.64, I² = 97%, p<0.00001). The considerable heterogeneity identified in the meta-analysis is probably attributable to variations in study protocols, Acupressure methods, and the characteristics of participants. Discrepancies in the implementation of Acupressure, including factors such as pressure intensity, duration, and the specific Acupoints selected, may have played a role in this heterogeneity. Furthermore, variations in the quality of the studies, including issues like the absence of blinding or inadequate allocation concealment, could influence the outcomes. These findings suggest that Acupressure may be a beneficial non-pharmacological intervention for pain management during labor. However, the high heterogeneity indicates that further research is needed to understand the varying effects across different contexts.

Fig. 6

Forest plot of the pooled MD of the effect of Acupressure versus no intervention on the labor pain intensity

3-2. Sub-groups analysis

The subgroup analysis was conducted based on the number of Acupressure points. Studies that used a single point were compared with those that simultaneously utilized several points for Acupressure. Overall, both single-point (MD = −2.29, 95% CI −3.01 to −1.57, p < 0.00001) and multi-point Acupressure (MD = −2.40, 95% CI −3.34 to −1.47, p < 0.00001) appear to have positive effects compared to no intervention. However, individual study weights and confidence intervals should be considered when interpreting these results.

3-3. Sensitivity analysis

Sensitivity analysis across all scenarios consistently demonstrated that the effect size remains unchanged. Regardless of variations in study characteristics or inclusion criteria, the overall impact remains stable.

3–4. Publication Bias

Figure 7 shows the funnel plot of the effect of Acupressure versus no intervention on labor pain intensity. The funnel plot comparing single and multi-acupoint interventions reveals moderate symmetry, suggesting a lower likelihood of significant publication bias. However, slight asymmetry is visible, with smaller studies showing more variable results. Multi-acupoint studies, represented by red diamonds, exhibit wider dispersion, indicating heterogeneity in outcomes, possibly due to variations in the number, combination, or application of acupoints. Conversely, single acupoint studies, shown as black squares, cluster more closely around the MD line, reflecting more consistent findings. The asymmetry at the lower precision end suggests potential underreporting of studies with non-significant or less favorable results, particularly for multi-acupoint interventions. This emphasizes the importance of additional high-quality studies to ensure comprehensive evidence for comparing these approaches.

Fig. 7

Funnel plot of the effect of Acupressure versus no intervention on the labor pain intensity

Certainty of evidence

Table 3 presents the GRADE profile of evidence. The certainty of evidence regarding the effect of Acupressure in comparison to touch was assessed as low. This assessment reflects a two-level downgrade due to significant concerns regarding bias and the possibility of publication bias. Furthermore, the certainty of evidence for the effect of Acupressure versus sham was also rated as low, with a similar two-level downgrade accepted due to serious risks of bias and heterogeneity. Lastly, the evidence grading for the effect of Acupressure compared to no intervention was classified as moderate, with a one-level downgrade attributed to a serious risk of bias.

Table 3 GRADE evidence profile

While Acupressure has demonstrated potential benefits for pain relief during labor, the low certainty of evidence indicated in the GRADE profile emphasizes the need for more rigorous randomized controlled trials (RCTs) to substantiate these claims. The downgrades related to serious bias risks and heterogeneity suggest that, although there may be some positive outcomes associated with Acupressure, the dependability of these findings remains uncertain. To validate Acupressure as a reliable intervention in obstetric care, it is crucial to conduct high-quality research that addresses these issues. Future investigations should focus on minimizing biases and employing standardized protocols to improve the consistency and validity of results. By developing well-structured randomized controlled trials, researchers can offer clearer insights into the actual effectiveness of Acupressure during labor. Only through thorough investigation and enhanced evidence quality can we confidently incorporate Acupressure into pain management strategies for childbirth, potentially leading to improved GRADE ratings in subsequent evaluations.

Discussion

The current systematic review and meta-analysis seeks to consolidate and critically evaluate the efficacy of Acupressure in alleviating labor pain, drawing from 37 RCTs. In this analysis, heterogeneity was assessed using the I² statistic, with thresholds of 25%, 50%, and 75% representing low, moderate, and high levels of heterogeneity, respectively. Sensitivity analyses were conducted by omitting studies that exhibited large effect sizes or a significant risk of bias, while subgroup analyses were utilized to investigate potential sources of heterogeneity. Outliers were detected through a visual examination of forest plots and were excluded in the sensitivity analysis to enhance the reliability of the findings.

Sham Acupressure and blank controls are typically designed to help mitigate bias when assessing Acupressure’s specific effects. The analysis of 15 RCTs found that Acupressure had a statistically significant effect on reduced labor pain intensity compared to touch. In recent years, there have been some meta-analyses on the effect of Acupressure on labor pain intensity that consistence with our results [5, 6, 57, 58]. A meta-analysis conducted in 2020, which included 18 RCTs, found that Acupressure significantly reduced labor pain in the intervention group compared to the control group [5]. In this study, Acupressure was not compared with Sham intervention. Most studies used points SP6 and LI4 for their interventions. Acupressure on the SP6 and L14 points can help to reduce labor pain. By activating and increasing the production of endorphins, Acupressure at these points can reduce pain. Activity in the large and small nerve fibers influences the sensation of pain. Pain impulses travel through small-diameter fibers. These nerve fibers are responsible for blocking the impulses that pass through these small-diameter fibers. Stimulating acupuncture points on the skin's surface, which contain large-diameter sensory nerve fibers and blood vessels, helps close the gates on the transmission of pain-causing impulses, thereby reducing or eliminating pain [59]. The results of another meta-analysis of nine articles related to the effect of Acupressure on significantly reducing dysmenorrhea pain showed that Acupressure could reduce primary dysmenorrhea pain in women. Authors stated that non-pharmacological management or complementary therapy to Acupressure therapy can be considered a way to treat primary dysmenorrhea because of its high level of safety and more affordable costs. Further studies are needed to explore the impacts of variables such as Acupressure strength, intensity, and duration on fatigue reduction [60].

Another finding was that the results of 5 RCTs demonstrated a significant effect favoring Acupressure over Sham treatment. To perform a Sham Acupressure, lightly touch the acupoint location or areas other than the actual acupoints without applying any pressure. A meta-analysis, conducted up to 2018, compared Acupressure to sham Acupressure in eight trials. The combined results of these studies yield a significant pain reduction in favor of Acupressure immediately after treatment at the active phase of labor and the transitional phase of labor. There was also a significant difference between the groups in favor of Acupressure for 30 min and 1 h after treatment. However, after 2 hours of treatment, they found no significant difference between the groups [61]. Based on a systematic review and critique (2015) with sixty-six RCTs showed that Acupressure therapy was a beneficial approach in managing a variety of health problems, and the therapeutic effect was found to be more effective in the true Acupressure groups than that in the sham comparative groups. The authors stated that they cannot conclude about the association between sham alternatives and treatment outcomes due to clinical heterogeneity in the trials. Additionally, they recommend the use of non-acupoints, but caution should be exercised when locating them. Instead of stimulating the active intervention acupoint, investigations using single sham acupoints on hands or legs should use identical Acupressure devices. In pain studies, avoid activating sham acupoints [62]. Bal et al. (2024) conducted a sham-controlled trial aimed to analyze the effects of Acupressure on pain, anxiety, and vital signs in patients who underwent coronary angiography. Results showed that, compared to the sham and control groups, the pain scores in the Acupressure group decreased significantly after Acupressure [63].

We used a random-effects model because we identified substantial heterogeneity between studies. The review of the articles revealed that the frequency of Acupressure for pain reduction lasts approximately 30 minutes, potentially influencing the reduction of pain in pregnant women during labor. In this research, the sham procedures utilized in the studies varied significantly; some employed thumb pressure on non-acupoints, while others implemented placebo devices. To enhance the validity of future trials, it would be beneficial to adopt a more rigorous and standardized sham protocol, such as applying pressure to non-acupoints with identical devices, thereby ensuring consistent control of the placebo effect across different studies.

Another results analysis of 25 RCTs showed a significant effect of Acupressure versus no intervention on pain relief during labor. We obtained the same results when we compared Acupressure to usual care without any intervention. The usual care was specific to each trial and involved measures other than the intervention treatments, such as the presence of a nurse and/or midwife, massage in the lower back region, breathing exercises, and liberty of movement. Although the effectiveness of Acupressure in relieving pain has been confirmed, the heterogeneity is relatively large. This could be attributed to the wide range of research subjects included in this study, aside from chance variation and methodological differences, clinical differences as they relate to the study participants (age, parity, mood, and tolerance) are presumably the source of these observed differences of individual study results. This could also be due to factors such as the choice of acupoints and massage duration. We recommend designing and implementing a standard methodology for labor pain in future research, taking into account the variations in pressure points and intervention duration across the reviewed studies.

Overall, we deemed none of the included studies low-risk across all domains. Seventy-five percent assessed the domain of random sequence generation as low-risk. They rated the evidence's certainty for the effect of Acupressure compared to touch, Sham, or no intervention as low. Variations in the methods of randomization and allocation concealment—such as the use of sealed envelopes versus computer-generated techniques—may have led to selection bias. Additionally, the lack of blinding in numerous studies could have contributed to performance and detection bias, as both participants and outcome assessors might have been aware of the intervention being provided. Such biases can potentially influence the reported treatment effects, particularly in studies where outcomes, such as pain intensity, depend on subjective assessments. To establish Acupressure as a credible intervention in obstetric settings, it is essential to conduct high-quality research that addresses these concerns. Future studies should aim to minimize biases and utilize standardized protocols to enhance the consistency and validity of their findings. By producing well-designed RCTs, researchers can provide clearer insights into the true efficacy of Acupressure during labor. Only with rigorous investigation and improved evidence quality can we confidently integrate Acupressure into childbirth pain management strategies, potentially increasing our GRADE ratings in future assessments. We conducted funnel plot analyses when 10 or more studies were included in the analysis. For the comparison of Acupressure versus touch, funnel plot asymmetry was observed, which led to the decision to downgrade the evidence. This finding underscored the importance of exercising caution when interpreting the overall effect size and highlighted the need to consider study characteristics and their potential influence on the observed asymmetry.

Our study benefits from several strengths. Firstly, we focused our review on the effect of Acupressure as a standalone treatment, excluding studies involving mixed therapies, and conducted a subgroup study of sham Acupressure or blank control in the control group to verify whether Acupressure’s effectiveness in treating labor pain. Secondly, our review included 37 RCTs with larger sample sizes and a variety of Acupressure points. Thirdly, the included studies were conducted at multiple locations and in different countries, covering a diverse range of ethnicities and cultures, potentially reducing selection bias and improving external validity. Fourthly, we conducted sensitivity analysis and funnel plot, indicating that the meta-analysis was stable, robust, and free from publication bias. Lastly, in this review, no time or linguistic restrictions were applied when searching the databases. There are limitations to consider when interpreting these results. The studies included in this meta-analysis exhibited a high level of statistical heterogeneity due to the use of different methodologies from different countries. There is the potential for publication bias that may have arisen from the failure to identify unpublished negative studies. There is a potential for exaggerating the impact of the therapy in interventions, particularly in trials where blinding and/or allocation concealment are not properly implemented. Finally, the overall quality of the studies was low, particularly concerning allocation concealment and participant and personnel blindness.

Future studies

Future research should aim to tackle the limitations identified in our analysis, including the selection of specific acupoints (for instance, SP6 or LI4), the duration of sessions (such as 30 minutes per session), and the intensity of pressure applied (for example, by employing standardized scales for pressure measurement). Maintaining consistency in these factors will reduce variability and improve results'comparability across various studies. Larger, well-designed RCTs are essential to validate the effectiveness of Acupressure in labor pain management. Additionally, studies exploring the long-term effects of Acupressure on maternal and neonatal outcomes are warranted. Systematic reviews examining the integration of Acupressure into standard obstetric care could provide further insights into its role within diversified pain management strategies.

Public health implications

The results of our meta-analysis underscore the potential of Acupressure as a non-drug approach for managing labor pain. This could have significant implications for public health, especially in areas where access to pain medications is restricted or where women prefer non-pharmacological methods. Greater awareness and training in Acupressure for healthcare providers could support its wider adoption, promoting a more comprehensive approach to maternity care and improving the overall birthing experience for women.

Clinical implications

From a clinical perspective, Acupressure may serve as a valuable tool for alleviating labor pain, improving patient satisfaction, and potentially decreasing reliance on pain-relieving medications. Healthcare professionals should explore integrating Acupressure into standard labor care practices, particularly for women interested in alternative or complementary pain management strategies. Additionally, educating pregnant women about Acupressure techniques could empower them to take a more active role in managing their pain during childbirth.

Conclusion

The findings from this study affirm that Acupressure represents a noninvasive technique capable of significantly alleviating pain. However, to create evidence-based guidelines, further clinical trials with standardized intervention procedures are required.

Appendix

Table 4 Appendix 1 Search strategy