Fascial plane blocks in labor: promise or illusion? A narrative review with expert opinion

Abstract

Background

Neuraxial analgesia represents the gold standard for labor pain management, providing superior efficacy and safety for both mother and fetus. However, its use is not always feasible due to medical contraindications, technical difficulties, or patient preference. Fascial Plane Blocks (FPBs) have emerged as potential alternatives, yet evidence regarding their effectiveness in labor remains limited. The purpose of this study was to synthesize the current evidence on FPBs for labor analgesia and to offer expert insight into their potential role, benefits, and limitations within modern obstetric practice.

Material and Methods

A systematic search of PubMed, EMBASE, and the Cochrane Library (1985–2025) was conducted following PRISMA guidelines. Eligible studies included laboring women aged ≥ 18 years undergoing analgesia with FPBs. Case reports, case series, and letters to the editor were included due to the scarcity of high-level evidence. Outcomes of interest were maternal pain scores, analgesic satisfaction, and maternal–fetal safety. Because of the marked heterogeneity in study designs, interventions, and outcome measures, a meta-analysis was not feasible; therefore, a narrative synthesis was performed, and qualitative methodological assessment was undertaken using validated tools.

Results

Eight studies met inclusion criteria. QLB demonstrated promising analgesia in the first stage of labor, while lumbar and thoracic ESPBs yielded variable effects and inconsistent coverage during the second stage. Sacral ESPB showed potential as an adjunct when neuraxial techniques failed or were contraindicated. No major complications were reported; however, methodological limitations, small sample sizes, and inconsistent reporting hindered definitive conclusions. Fetal outcomes were rarely reported, and no long-term follow-up data were available.

Conclusions

Current evidence does not support FPBs as replacements for neuraxial analgesia. Their use should be restricted to highly selected cases where neuraxial techniques are not feasible. Importantly, there is no predefined formula for managing labor pain—analgesic strategies must be individualized according to clinical context, patient preference, and available resources. High-quality prospective studies are necessary to clarify the role of FPBs in labor.

Study design

Neuraxial analgesia is recommended as "the gold standard" for labor pain relief, however despite its clear advantages there are situations where its use is contraindicated or unfeasible. Therefore, this review aims to summarize the available data Fascial Plane Blocks for labor pain relief. To gain a better understanding of the critical issues in current literature, expert commentary on the topic were included.

Introduction

Labor pain is widely recognized as one of the most intense and meaningful experiences in a woman’s life [1]. Effective analgesia must therefore be tailored to support both maternal comfort and fetal well-being [1, 2]. Neuraxial Analgesia (NA) remains the gold standard for labor pain management, offering excellent analgesic efficacy and consistently favorable maternal and fetal outcomes [3, 4]. However, NA is not universally feasible [5]. Thrombocytopenia, coagulopathy, ongoing anticoagulant therapy, anatomical difficulties, and significant medical comorbidities may preclude its safe use [5, 6].

With the rising number of pregnant patients presenting with complex medical conditions, the need for effective non-neuraxial alternatives has become increasingly apparent [7]. Historically, pudendal and paracervical blocks were used for labor analgesia, but their role has declined in parallel with the widespread adoption of neuraxial techniques [2, 7].

In recent years, Fascial Plane Blocks (FPBs) have gained growing attention as flexible tools within regional anesthesia [8–10]. Techniques such as the Erector Spinae Plane Block (ESPB) and other emerging fascial plane approaches have demonstrated substantial value across multiple clinical scenarios, prompting interest in their potential applicability for labor analgesia [8–11]. Their motor-sparing profile and favorable safety characteristics make them appealing in selected obstetric settings, particularly when neuraxial techniques are difficult or contraindicated [7, 12, 13]. Despite this evolving interest, significant gaps remain in the literature [10, 14]. To date, no systematic review has comprehensively evaluated FPBs as alternatives to NA for labor pain management. Given the growing number of case reports, small clinical studies, and advances in ultrasound-guided regional techniques, a critical reassessment of available evidence is warranted.

Objective

Accordingly, this review aims to address this unmet need by synthesizing current research and providing an updated, comprehensive overview of FPBs for labor analgesia. The objective is to evaluate their effectiveness, safety, and potential role within modern obstetric practice, while offering expert commentary on the emerging place of these approaches in labor pain management.

Materials and methods

Study design and reporting standards

This review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines [15]. The overall flow of study identification, screening, and selection is illustrated in Fig. 1.

Fig. 1.

PRISMA flowchart

Eligibility criteria

The inclusion criteria were defined before initiating the review process and are summarized in Table 1.

Table 1.

Eligibility criteria for inclusion in the review

Item	Eligibility Criteria
Patients	Women in labor over 18 years of age
Interventions	FPBs (Paravertebral block, QLB, ESPB, S-ESPB)
Articles language	English
Comparison	Comparison of labor pain relief among the above techniques and/or against an active or passive control group
Primary endpoint	- Assessment of maternal satisfaction with pain relief, using verbal reports, VAS scores, or other validated pain assessment tools - Evaluation of opioid consumption
Secondary endpoint	Documentation of any perioperative complications associated with the above anesthesia techniques
Types of studies evaluated	Randomized clinical trials, review, observational study, case series, case report, letter to editor

Abbreviations: FPBs Fascial Plane Blocks, ESPB Erector Spinae Plane Block, S-ESPB Sacral-Erector Spinae Plane Block), QLB Quadratus Lumborum Block, VAS Visual Analogue Scale

We considered all available studies involving women in labor aged 18 years or older who received analgesia through FPBs, including Paravertebral Block, Quadratus Lumborum Block (QLB), ESPB, and Sacral-ESPB.

The primary outcomes of interest were maternal satisfaction—interpreted in terms of labor pain relief and opioid requirements. Because each study used its own terminology and assessment tools (verbal reporting, or other validated scales), we respected the authors’ original definitions when interpreting these outcomes.

Secondary outcomes included any maternal or fetal periprocedural complications associated with the analgesic technique.

Given the limited availability of high-level evidence in this field, we decided a priori to also include case reports, case series, and letters to the editor that provided relevant clinical information. This decision was incorporated into the predefined eligibility criteria.

Search strategy

A comprehensive search was carried out in PubMed, EMBASE, and the Cochrane Library, covering publications from 1985 to 2025 and limited to articles written in English.

The search strategy included terms related to obstetric anesthesia and FPBs:

“labor analgesia”, “labor pain”, “obstetric analgesia”, “childbirth anesthesia”, “fascial plane blocks”, “erector spinae plane block”, “ESPB”, “sacral erector spinae plane block”, “S-ESPB”, “quadratus lumborum block”, “QLB”, and “paravertebral block”.

Two authors (D.C., F.C.) independently screened search results. Disagreements were resolved by discussion until a consensus was reached.

Study selection

Study selection occurred in several stages. First, duplicates and abstracts without an available full-text version were removed. The remaining abstracts were screened for relevance according to the predefined inclusion and exclusion criteria.

Full-text articles deemed potentially eligible were then assessed in detail. Their reference lists were also reviewed to identify additional studies not captured during the initial search.

Because literature on FPBs in labor is still sparse, particularly regarding controlled trials, we intentionally broadened the scope to include lower-level evidence such as case reports and case series. This was planned in advance and reflected in the eligibility criteria.

Data extraction

Data were extracted by one author (A.C.) using a standardized proforma in Microsoft Excel and independently verified by a second author (G.R.).

Extracted variables included general bibliographic information, study design, characteristics of the intervention (type of block, medications, dosages), and reported outcomes. Given the clinical and methodological heterogeneity among the included studies, we did not perform a meta-analysis. Instead, we conducted a narrative synthesis of the available evidence.

Qualitative methodological assessment

All included studies, with the exception of letters to the editor, underwent qualitative methodological evaluation conducted independently by three authors (D.C., F.C., P.S.) using Joanna Briggs Institute (JBI) tools appropriate for case reports and case series [16, 17].

Each domain of the JBI checklist was rated as low risk, unclear, or high risk. Final judgments were reached through consensus during a joint evaluation meeting.

Results

A total of 138 articles were initially identified. After screening and applying inclusion and exclusion criteria, 8 studies were selected for review. No data regarding paravertebral block has been found. A summary of the included studies is provided in Table 2.

Table 2.

Summary of Included Studies

Authors and Year of Publication	Study Type	Number of Participants	Anesthetic Techniques (Drugs and Dosages)	Outcome Measure	Analgesic Effect	Reported Complications
Vilchis-Renteria et al., 2020 [18]	Case Series	4	ESPB; 1) 20 mL of 0.2% Ropivacaine (for each side) 2) Unilateral ESPB 20 mL of 0.5% Ropivacaine 3) Unilateral ESPB 20 mL of 1.5% Lidocaine +  1:200 000 Adrenaline 4) Unilateral ESPB 20 mL of 0.5% Lidocaine +  1:200 000 Adrenaline	Labor pain relief evaluated with NRS	Decrease in pain intensity after administration of ESPB in all clinical cases (Mean ΔNRS = 4)	Cesarean delivery performed under spinal anesthesia for obstructed labor — Patient Two
de Haan et al., 2020 [19]	Case Report	1	pQLB 20 mL of 0.5% Bupivacaine (for each side)	Pain evaluation (patient’s verbal report)	Pain reduced in the first stage of labor	Absence of perceived uterine contractions during the second stage of labor
				Apgar Score	9 at 1 min 10 at 5 min
Paventi et al., 2024 [20]	Case Report	1	S-ESPB 30 mL of 0.3% Ropivacaine	Labor pain relief evaluated with NRS	Decrease in pain intensity 20 min after block with NRS reduction from 8 to 2	Cesarean delivery performed under spinal anesthesia for labor arrest
Martín Serrano et al., 2024[21]	Case Report	1	S-ESPB 20 mL of 0.25% Levobupivacaine (for each side)	Labor pain relief evaluated with VAS	Decrease in pain intensity 45 min after block with VAS reduction from 10 to 6	None reported
Shakery et al., 2024 [22]	Letter to Editor	None	None	None	None	None
Niraj et al., 2024 [23]	Case Series	10	ESPB 30 mL of 62.5 mg Bupivacaine + 100 mg Lidocaine (with 1:200.000 Epinephrine)  + 4 mg Dexamethaso ne (for each side)	Labor pain relief evaluated with NRS	Abdomina l pain: mean ΔNRS = 8 Perineal pain: mean ΔNRS = 5	Cesarean delivery performed for fetal distress in two patients
Yasar et al., 202 [24]	Case Series	3	10 mL of 0.25% Bupivacaine (for each side)	Labor pain relief evaluated with NRS	Mean ΔNRS = 3	Tachycardia, Hypertension and NRS pain score increase (7–8/10) during the second stage of labor – all three patients
Marrone et al., 2024 [25]	Letter to Editor	None	None	None	None	None

Abbreviations: ESPB Erector Spinae Plane Block, S-ESPB Sacral-Erector Spinae Plane Block, pQLB posterior Quadratus Lumborum Block, LA Local Anesthetic, VAS Visual Analogue Scale, NRS Numerical Rating Scale

Notes: -Δ pain score: the numerical change in pain intensity before and after the intervention (e.g., VAS 8 to 4 corresponds to ΔVAS 4). Mean Δ pain score: the average reduction in pain across the study population (e.g., individual ΔVAS values of 4, 5, and 3 result in a mean of 4). -For bilateral procedures, the stated volume indicates the amount injected on each side, unless otherwise noted. -Measures of maternal satisfaction and pain relief differed across studies; reported outcomes are presented according to each source’s original definitions. -None (Not applicable for this study)

Ultrasound-Guided QLB

QLB has attracted interest as an option for labor analgesia because it can provide sensory coverage from approximately T4 to L2—an anatomical distribution particularly relevant for pain control during the first stage of labor [26, 27]. This technique involves the deposition of local anesthetic (LA) adjacent to the quadratus lumborum muscle, offering an analgesic duration that may be sufficient for early labor, especially in multiparous women [28]. The posterior approach (pQLB), performed at the interface between the quadratus lumborum muscle and the L4 transverse process, produces a broad and reliable sensory spread [26, 28, 29].

In a case report by De Haan et al., a woman with hemophilia A underwent bilateral pQLB using 20 mL of 0.5% Bupivacaine per side for labor analgesia. The block provided sustained pain relief throughout the first stage of labor (approximately 3–4 h). Although the patient reported an absence of uterine contraction awareness during this phase, labor progressed normally, ultimately resulting in an uncomplicated vaginal delivery with a favorable neonatal outcome [19].

Ultrasound-Guided ESPB

ESPB has gained traction as a potential option for labor analgesia because its injectate can spread across multiple vertebral levels, providing both somatic and visceral pain relief [30, 31]. The technique involves depositing LA between the transverse process and the erector spinae muscle, offering a favorable safety profile compared with neuraxial procedures [12, 32].

In a case series by Vilchis-Renteria et al., four women in the first stage of labor (6–8 cm cervical dilation) underwent lumbar ESPB at the L4 level [18]. For each women, different LA solutions were used: 20 mL of 0.2% Ropivacaine bilaterally, 20 mL of 0.5% Ropivacaine unilaterally, 20 mL of 1.5% Lidocaine with 1:200,000 Epinephrine unilaterally, 20 mL of 0.5% Lidocaine with 1:200,000 Epinephrine unilaterally. All four patients reported complete pain relief, with a 3–6 point reduction on the Numerical Rating Scale (NRS), and achieved analgesia lasting between 60 and 120 min. No adverse events were observed.

In another case series from 2021, three laboring women received bilateral thoracic ESPB at the T11 level (10 mL of 0.25% Bupivacaine per side), resulting in marked pain reduction during the first stage of labor [24]. However, analgesia proved insufficient during the second stage, requiring supplemental analgesic intervention.

The largest reported experience comes from Niraj et al., who studied ten nulliparous women receiving bilateral lumbar ESPB (L4) after inadequate pain control following IV Tramadol [23]. For the first six patients, the injectate consisted of a 30 mL mixture containing Bupivacaine (62.5 mg), Lidocaine (100 mg with 1:200,000 Epinephrine), and Dexamethasone (4 mg). Observing robust analgesia and recognizing the practical limitations of catheter placement during active labor, the remaining four women were treated with single-shot bilateral blocks. All patients experienced complete relief of abdominal pain. Two ultimately required cesarean delivery due to fetal distress, although these events occurred later in labor and were not temporally associated with the block; the authors reported no plausible mechanism linking ESPB to the fetal compromise.

A further case report by Martín Serrano et al. described a parturient with factor XI deficiency who received bilateral lumbar ESPB (20 mL of 0.25% Levobupivacaine per side), resulting in significant pain reduction during labor [21].

Ultrasound-Guided Sacral-ESPB

The Sacral-ESPB technique, initially introduced for pilonidal sinus surgery, has more recently been considered as a potential technique for labor analgesia [33]. By depositing LA at the S1–S2 level, the block targets both sacral and lower lumbar dermatomes [34]. It has been proposed either as a complement to Epidural Analgesia (EA) or as an alternative when NA are contraindicated or not feasible.

Building on the concept that inadequate sacral coverage can contribute to EA failure and negatively affect maternal comfort—particularly during the second stage of labor—Marrone et al. suggested, in a letter to the editor, combining standard epidural techniques with Sacral-ESPB. As an alternative strategy for patients unable to receive NA, the authors proposed the use of early bilateral continuous lumbar ESPB (L1–L2), followed by a single-shot Sacral-ESPB with 30 mL of 0.3% Ropivacaine in the later stages of labor.

A clinical case reported by Paventi described the use of Sacral-ESPB (single-shot administration of 30 mL of 0.3% Ropivacaine) in a nulliparous woman [20]. The patient experienced a marked decrease in pain, with the NRS score dropping from 8 to 2; however, she ultimately underwent cesarean delivery under spinal anesthesia due to labor arrest.

Although no ESPB-related complications were reported in the studies included in this review, the volume-dependent nature of the technique warrants caution. As highlighted by Shakeri A. et al., the potential risk of Local Anesthetic Systemic Toxicity (LAST) cannot be entirely ruled out [22].

Methodological quality assessment

The methodological appraisal of the three case reports revealed variable reporting quality (Fig. 2). Two reports — Paventi et al. (2024) and Martín Serrano et al. (2024) — were judged to have an unclear overall risk of bias. The main limitations involved insufficient detail in the description of assessment methods and incomplete documentation of post-intervention outcomes. Both studies also received unclear or high-risk ratings in key domains such as the clarity of the clinical assessment and the articulation of the take-home message. In contrast, the case report by de Haan (2020) met all JBI appraisal criteria and was assessed as low risk of bias. This study demonstrated strong methodological transparency, comprehensive reporting, and complete documentation across all evaluated domains. Across the case reports, the domains most commonly associated with reporting gaps included the specification of outcome assessment methods and the clarity of post-intervention findings.

Fig. 2.

Summary plot of the methodological quality assessment of the included case reports, evaluated using the Joanna Briggs Institute (JBI) Critical Appraisal Checklist for Case Reports. The plot illustrates the proportion of items rated as low risk, unclear risk, or high risk across key methodological domains for the studies by Paventi S. et al. (2024), Martín Serrano P. (2024), and De Haan J. (2020)

All three case series exhibited an unclear overall risk of bias (Fig. 3). Recurrent issues were identified in several domains, particularly the reporting of: explicit inclusion criteria, consecutive patient recruitment, and the presence of a statistical analysis. The case series by Niraj et al. (2024) and Vilchis Rentería et al. (2020) showed the highest number of methodological concerns, with multiple domains rated at high risk. The study by Yasar et al. (2021) demonstrated fewer high-risk elements compared to the others but still lacked adequate detail regarding study setting and documentation of clinical history. Overall, the case series displayed substantial variability in methodological rigor, with several domains insufficiently addressed, limiting the robustness of conclusions drawn from these studies.

Fig. 3.

Summary plot of the methodological quality assessment of the included case series, evaluated using the Joanna Briggs Institute (JBI) Critical Appraisal Checklist for Case Series. The plot displays the distribution of low-risk, unclear-risk, and high-risk ratings across methodological criteria for the case series by Niraj G. et al. (2024), Yasar E. (2021), and Vilchis Rentería J.S. (2020)

Discussion

The available evidence indicates that FPBs provide variable but potentially meaningful analgesia during labor. QLB—particularly the pQLB—was associated with effective pain relief during the first stage of labor, with encouraging results in multiparous women. ESPB showed more heterogeneous outcomes, often providing adequate analgesia in the first stage of labor but with limited effectiveness during the second stage. The Sacral-ESPB demonstrated promising analgesic potential, especially as an adjunct to EA or NA were not feasible, though more robust data are required to establish its efficacy and safety. The methodological quality of the included studies was generally low to moderate. Most case reports and case series lacked consistency in outcome reporting, clear assessment methods, and statistical analysis, limiting the strength of the conclusions that can be drawn.

This review carries several important implications for the management of labor pain. The evidence suggests that FPBs may offer meaningful analgesia when NA are contraindicated, technically difficult, or not preferred [7, 12, 35, 36]. The QLB, for example, is already well established as an analgesic option in the postoperative setting following cesarean delivery and gynecologic procedures such as hysterectomy [35, 37]. Its mechanism of action is thought to involve spread of LA toward the thoracolumbar paravertebral space, producing both somatic blockade of the abdominal wall and visceral analgesia [26, 27]. This hypothesis aligns with one of the cases included in this review, in which a patient receiving a pQLB reported an absence of uterine contraction awareness—suggesting potential involvement of visceral uterine innervation [19]. These observations are further supported by the cadaveric findings of Dam et al. (2017), which demonstrated that injectate used in QLB can reach neural pathways supplying both abdominal and visceral structures [38]. Nonetheless, clinicians should exercise caution with QLB during pregnancy, as physiological alterations such as heightened neural sensitivity and progesterone-mediated changes may influence dosing requirements and drug spread [39].

ESPB, originally described for neuropathic thoracic pain, has since been applied to various abdominal and thoracoabdominal procedures [40]. Although isolated reports have described hemodynamic instability following ESPB—particularly when large volumes are used—none of the studies included in this review documented clinically significant hemodynamic effects [41]. MRI studies have demonstrated that injectate from ESPB may extend into the epidural space on both sides, suggesting that even unilateral injections may produce bilateral analgesia [42, 43]. This concept is consistent with the findings of Vilchis Rentería et al., who observed bilateral pain relief with both unilateral and bilateral ESPB during labor, although the degree of analgesia was variable and often incomplete (NRS 5–9/10) [18]. Such heterogeneity may reflect the unpredictable extent of epidural spread, which can influence block reliability.

From a bleeding-risk standpoint, current guidelines indicate that ESPB and Sacral-ESPB, which are performed in relatively superficial and compressible anatomical planes, may pose a lower hemorrhagic risk compared with deep, non-compressible plexus blocks [44]. In contrast, the QLB is classified as a deep, non-compressible technique and should therefore be approached with the same level of caution as neuraxial and other deep plexus blocks in patients receiving antithrombotic therapy [44]. Accordingly, the timing of anticoagulant interruption and the decision to perform the block should follow established recommendations from major societies such as ESAIC/ESRA, ASRA, and SOAP, particularly in obstetric patients with thrombocytopenia or coagulopathy [44–46]. Against this background, the case report included in this review provides a relevant observation: De Haan and colleagues successfully performed a posterior QLB—despite its deep nature—in a multiparous woman with Hemophilia A, without bleeding complications after appropriate factor VIII replacement [19].

This review presents several important limitations that must be considered when interpreting its findings. First, the overall quality of the available evidence is low. Most included studies consist of case reports and case series, characterized by small sample sizes, lack of control groups, and substantial variability in reporting standards. Methodological appraisal using JBI tools revealed frequent issues such as unclear inclusion criteria, inconsistent outcome assessment, incomplete follow-up, and absence of any statistical analysis, limiting the strength and generalizability of the conclusions.

Second, the high degree of clinical and technical heterogeneity across studies restricts meaningful comparison. The blocks described differed in type (QLB, ESPB, Sacral-ESPB), anatomical level, unilateral or bilateral performance, local anesthetic concentration and volume, and timing relative to the stages of labor. This heterogeneity precludes identification of standardized techniques or dosing strategies and complicates the interpretation of analgesic efficacy.

Third, no randomized controlled trials or comparative observational studies are currently available. As such, the effectiveness of fascial plane blocks relative to neuraxial analgesia—the accepted gold standard—or to systemic analgesic strategies cannot be determined. Similarly, the safety profile of these blocks in pregnant patients remains largely inferred rather than empirically established.

Fourth, outcome reporting was inconsistent and often incomplete. Pain relief was assessed using different tools and time points across studies, and key obstetric outcomes—such as labor progression and mode of delivery—were not systematically documented. Importantly, validated fetal outcomes were rarely reported: Apgar scores were documented in only one study, and no data were available regarding umbilical cord gases, neonatal adaptation beyond the immediate postpartum period, or any structured neonatal evaluation. Likewise, no study provided information on long-term maternal or fetal follow-up, preventing any assessment of potential delayed effects or longer-term safety considerations.

Finally, the predominance of positive case reports raises the possibility of publication bias, which may overestimate the apparent benefits of these interventions while underreporting ineffective or adverse outcomes.

Expert opinion

Labor pain presents a unique clinical challenge because its neurophysiologic profile evolves dynamically over the course of labor [47]. During the first stage, visceral nociceptive input arises from T10–L1, while the second stage engages somatic afferents conveyed through the pudendal nerve (S2–S4) [4]. Additional contributions from the ilioinguinal and genitofemoral nerves further complicate the sensory anatomy of the perineum. Any analgesic technique intended to replace NA must therefore adapt to this shifting pattern of nociception—an ability that current FPBs do not possess [4].

At present, the use of FPBs as a primary modality for labor analgesia is constrained by several physiological, neuroanatomical, and safety considerations. Most FPBs provide relatively fixed dermatomal coverage and rely on high-volume LA spread, which limits their capacity to modulate analgesia in response to the real-time variability of labor pain. Moreover, the selective blockade of A-delta and C fibers [48], essential for effective modulation of visceral and somatic labor pain, is inconsistent with fascial plane injections, whose mechanisms involve indirect neural exposure and unpredictable spread.

Safety considerations are particularly critical in obstetric patients, as pregnancy induces profound pharmacokinetic and pharmacodynamic changes—including increased cardiac output, reduced protein binding, hormonal modulation, and venous congestion—that collectively enhance systemic absorption of LA and increase susceptibility to LAST [4, 49]. Added to this is the fact that FPBs rely on relatively large, fixed volumes of LA administered as a single, non-titrable dose, making drug exposure less predictable than infusion epidural catheter infusion. The use of adjuvants introduces additional concerns: dexmedetomidine may destabilize maternal hemodynamics, whereas epinephrine can mask or delay early signs of LAST. Another important safety consideration is the Ferguson reflex, a key physiological mechanism for effective labor progression [4, 50]. Compression of the fetal head against the pelvic floor triggers somatic and visceral afferents that stimulate oxytocin release and generate the characteristic “urge to push,” which is essential for coordinated maternal expulsive efforts. FPBs that may influence sacral sensory pathways—such as the Sacral-ESPB—have the potential to attenuate this reflex, thereby impairing expulsive effectiveness and altering the physiologic course of labor. For all these reasons, FPBs in the intrapartum setting should be approached with great caution, applying the principle of “less is more” when selecting techniques and determining anesthetic dosing to ensure optimal maternal–fetal safety.

Technical feasibility represents an additional barrier. ESPB—whether thoracic, lumbar, or sacral—typically requires prone or stable lateral positioning for optimal imaging and needle alignment. These positions are often poorly tolerated during labor, contributing to reduced accuracy and increased operator dependence. Unpredictable epidural spread has been documented in thoracic and lumbar ESPB, posing risks of motor impairment that may interfere with maternal mobility and pushing—both critical for a positive birth experience [14, 32]. S-ESPB introduces further challenges, as it could theoretically disrupt sacral sensory pathways important in guiding second-stage mechanics [32]. Similarly, QLB offers attractive theoretical benefits through possible paravertebral spread and visceral analgesia, yet its deeper approaches (type 2 and type 3) require lateral positioning and carry procedural risks heightened in pregnancy due to altered pelvic and abdominal anatomy [28]. Type 1 QLB is more feasible in the supine position, but provides limited coverage that may be insufficient for labor [28].

Given these factors, FPBs cannot currently be recommended as substitutes for NA in labor. Their use should remain highly selective, reserved for specific situations where neuraxial techniques are not feasible. Conversely, FPBs may have a more appropriate and safer role in postoperative analgesia after cesarean delivery, where analgesic targets are stable, titration is less critical, and systemic exposure can be more carefully controlled [13, 32, 37]. Ultimately, labor analgesia must prioritize maternal safety and the quality of the overall childbirth experience—not merely the reduction of pain at a single moment during labor. While FPBs are promising tools with expanding applications in regional anesthesia, their current limitations, particularly regarding safety, dosing predictability, and adaptability to the neurophysiologic transitions of labor, restrict their role in intrapartum analgesia. Until more robust evidence becomes available, NA remains the standard of care.

Conclusions

In light of the current evidence, FPBs cannot yet be considered a reliable alternative to neuraxial analgesia, which remains the gold standard in terms of safety, titratability, and overall efficacy. Their use should therefore be reserved for highly selected clinical scenarios in which the potential benefits clearly outweigh the technical and physiological limitations described.

Ultimately, this review reinforces the concept that there is no predefined formula for managing labor pain. Analgesic strategies must be individualized, taking into account the patient’s clinical condition, her preferences, the stage of labor, and the resources available. To better delineate the role of FPBs in labor analgesia, high-quality prospective studies with standardized maternal and neonatal outcome assessments are essential.

Abbreviations

NA

Neuraxial Analgesia

FPBs

Fascial Plane Blocks

EA

Epidural Analgesia

ESPB

Erector Spinae Plane Block

QLB

Quadratus Lumborum Block

pQLB

Posterior Quadratus Lumborum Block

PRISMA

Preferred Reporting Items for Systematic Reviews and Meta-Analysis

LA

Local Anesthetic

LAST

Local Anesthetic Systemic Toxicity

NRS

Numerical Rating Scale

IV

Intravenous

MRI

Magnetic Resonance Imaging

JBI

Joanna Briggs Institute

Authors’ contributions

A.C. and M.G.F. contributed to the conceptualization of the study; D.C. and F.C. performed the acquisition, analysis, and interpretation of data and prepared the figures; G.R. and P.S. drafted the main manuscript text; A.C., D.C., D.P.S., and G.S. critically revised the manuscript for important intellectual content. All authors read and approved the final version of the manuscript.

Funding

No funding to declare.

Data availability

Not applicable.

Declarations

Ethics approval and consent to participate

Not applicable.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.