Labor analgesia as stigma, uncertainty, and conditional privilege: a thematic analysis of online Q&A posts in Japan.

Developing a concise multivariable predictive model for cesarean delivery following neuraxial analgesia during labor: a prospective observational cohort study.

Abstract Background Post-episiotomy pain is a common postpartum discomfort among primiparous women. Epidural analgesia using the local anesthetic ropivacaine alone has limitations such as insufficient duration of postoperative analgesia and poor pain control in the mid-to-late postoperative period. This study aims to explore a more optimal postoperative analgesic regimen by evaluating the clinical efficacy and safety of ropivacaine with hydromorphone for post-episiotomy analgesia in primiparous women, with a focus on the duration of analgesia, pain control efficacy, recovery-related indicators, and the incidence of adverse events. Methods A randomized controlled trial was conducted involving 80 primiparous patients who received neuraxial labor analgesia and underwent episiotomy between April 2025 and September 2025. Patients were randomly allocated to either Group R (ropivacaine alone) or Group RH (ropivacaine with hydromorphone), with 40 patients in each group. Following delivery and umbilical cord clamping, Group R received epidural ropivacaine (20 mg) diluted in 6 mL of 0.9% sodium chloride, while Group RH received a combination of ropivacaine (20 mg), hydromorphone (0.4 mg), and 6 mL of 0.9% sodium chloride. The primary outcome was analgesic efficacy, specifically including the time to first pain onset after surgery and the Visual Analog Scale (VAS) scores at 6, 12, and 24 h postoperatively; the secondary outcomes were postoperative recovery parameters (time to first flatus and time to first ambulation) and the incidence of adverse events. Results Compared with Group R, the time to first onset of pain in Group RH was significantly prolonged, and the Visual Analog Scale (VAS) scores at 6, 12, and 24 h postoperatively were all lower than those in Group R ( p < 0.05), remaining at a low level. In addition, the total duration of first ambulation in parturients was longer than that in Group R, and the incidence of postoperative nausea was lower than that in Group R (all p < 0.05). There were no statistically significant differences in the time to first flatus, vomiting and motor block between the two groups ( p > 0.05). Conclusions Epidural administration of ropivacaine with hydromorphone following episiotomy significantly enhanced analgesic efficacy and duration, facilitated postoperative recovery, and reduced the incidence of adverse events in primiparous women. These findings support the clinical utility of hydromorphone as an adjunct to ropivacaine for post-episiotomy analgesia. Trial registration This trial was registered at https://www.medicalresearch.org.cn/ (ChiCTR2500101509) on April 25, 2025.

BACKGROUND Labor pain triggers robust hypothalamic-pituitary-adrenal-axis activation, releasing adrenocorticotropic hormone (ACTH)/cortisol that fuels systemic inflammation and predicts postpartum depression (PPD). Although epidural ropivacaine is standard in China, adding the κ-agonist butorphanol may synergistically block pain and restrain this neuroendocrine stress response, offering a novel strategy to protect maternal mental health. AIM To investigate the effects of the combined use of butorphanol and ropivacaine on the plasma levels of ACTH and cortisol in patients undergoing labor analgesia as well as the incidence of PPD. We also compared the incidence of adverse reactions between the two groups. This study aimed to evaluate the regulatory effects of drug combinations and their side effects on the stress response of pregnant women, providing a basis for clinical intervention. METHODS Between June 2020 and June 2023, 114 pregnant women were randomly divided into study and control groups, with 57 participants in each group. The research group received a combination therapy of butorphanol and ropivacaine, whereas the control group received a combination therapy of sufentanil and ropivacaine. All participants received combined spinal epidural anesthesia to alleviate delivery pain. The Visual Analog Scale was used to assess the pain levels at different timepoints. We compared the incidence of adverse reactions and evaluated the incidence of PPD in the delivery room at 2 hours, 1 day, and 7 days postpartum using the Edinburgh Postnatal Depression Scale. Venous blood samples were collected using a fully automated chemiluminescence analyzer to measure ACTH and cortisol. RESULTS The Visual Analog Scale scores of the study group were significantly lower than those of the control group at all timepoints (P < 0.05). In addition, the Edinburgh Postnatal Depression Scale scores of the study group on days 1 and 7 postpartum were significantly lower than those of the control group (P < 0.05), indicating a lower risk of PPD in the study group. There was no significant difference in 24-hour neonatal behavioral neurological assessment, 1-minute Apgar score, and total treatment cost between the two groups of newborns (P > 0.05), and no respiratory depression was observed. The incidence rates of adverse reactions were 5.26% and 17.54% in the study and control groups, respectively. Two hours after delivery, both groups showed a decreasing trend in ACTH and cortisol; however, the levels in the study group were significantly lower than those in the control group (P < 0.05). CONCLUSION The combination of butorphanol and ropivacaine for labor analgesia can significantly reduce pain scores in women and lower the risk of postpartum pain. Additionally, it reduces the incidence of adverse reactions without compromising the safety of both the mother and newborn. This effect may be attributed to the synergistic analgesic effects of the drugs, neuroendocrine regulation, and the improved psychological and physiological conditions of the mother.

Labor epidural analgesia (LEA) catheter failure and replacement is a common problem in obstetrical anesthesia. The relationship between LEA catheter replacement and labor analgesia maintenance regimen is not well defined. The primary study objective was to investigate whether maintenance with programmed intermittent epidural boluses (PIEB) is associated with fewer epidural catheter replacements than continuous epidural infusions (CEI). A secondary study objective was to investigate whether initiation of LEA by the combined spinal epidural (CSE) technique was associated with fewer catheter replacements than the common epidural (EPID) technique. A combined pre-post and historical cohort study was conducted with data retrieved between July 1, 2013, and December 31, 2019, to compare patients who received labor LEA initiated by either EPID or CSE (cohort study) and maintained with either PIEB or CEI (pre-post comparison), each in combination with patient-controlled epidural analgesia. The a priori primary outcome was catheter replacement. Secondary outcomes consisted of time until catheter replacement, incidence of catheter top-ups, incidence of catheter withdrawal, a collapsed composite index of catheter intervention, and time until catheter top-up. Data were analyzed using confounder-adjusted logistic regression and Cox proportional hazards regression, and primary factors were assessed for 2-way interactions. A total of 11,277 EPIDs and 4082 CSEs were included. A total of 13,177 were maintained with PIEB and 2182 with CEI. When considering the primary outcome, EPID was associated with a 1.28× increase in the odds of replacement of the LEA catheter compared to CSE (95% confidence interval [CI], 1.01-1.65; P = .049). However, CEI was not significantly related to the primary outcome of LEA catheter replacement (odds ratio [OR] = 1.19; 95% CI, 0.90-1.56; P = .21). Among secondary outcomes, CEI was associated with a 1.34× increase in the odds of at least 1 catheter top-up (95% CI, 1.17-1.55; P < .001), a 1.34× increase in the odds of catheter intervention (95% CI, 1.10-1.64; P = .004), and had a greater hazard ratio (HR) for shorter time until catheter top-up (HR = 1.29; 95% CI, 1.14-1.46; P < .001) compared to PIEB. LEA catheter replacement was more common with EPID than CSE, but not markedly different between CEI and PIEB. Clinician interventions to optimize analgesia were more common with CEI than with PIEB.

Labor analgesia is recommended for pain relief during childbirth. In settings with limited medical resources, elective induction with epidural analgesia is often adopted; however, this may increase healthcare costs and prolong hospitalization. The impact of different approaches to labor analgesia on delivery-related charges, epidural-to-delivery interval, and hospitalization remains unclear. This retrospective study evaluated 252 full-term pregnant women who received epidural labor analgesia at a Japanese university hospital. Parturients were categorized into elective induction (EI) and on-demand (OD) groups. Inverse probability of treatment weighting with stabilized inverse propensity scores was applied to minimize bias. After adjusting for patient data, the mean ratios of the outcomes of interest for EI and OD were estimated using a generalized estimating equation. The primary outcome was delivery-related charges, while secondary outcomes included epidural-to-delivery interval and length of hospital stay. Among eligible parturient, 62.3% (157/252) underwent EI, while 37.7% (95/252) received OD. After weighting, the mean delivery-related charges, epidural-to-delivery interval, and length of hospital stay were 621,380 yen, 37.0h, and 7.5days in the EI group, compared with 594,408 yen, 14.6h, and 6.5days in the OD group, respectively. The mean ratios (95% confidence interval) for delivery-related charges, epidural-to-delivery interval, and length of hospital stay were 1.04 (0.98, 1.10), 2.52 (1.90, 3.20), and 1.15 (1.08, 1.22), respectively. Elective induction with epidural labor analgesia was associated with longer labor duration and hospital stay, while no statistically significant difference in delivery-related charges was observed compared with the on-demand approach.

The impact of opioid-free labor epidural analgesia maternal and infant outcomes: a retrospective cohort study.

Whether heating local anesthetic solutions to core body temperature (37°C) for epidural labor analgesia reduces intrapartum fever incidence remains undefined in the current literature. This double-blind randomized controlled trial (RCT) enrolled 220 nulliparous parturients (18-35 years, American Society of Anesthesiologists [ASA] physical status II, term singleton pregnancy). Participants were randomized to receive epidural labor analgesia with 0.075% ropivacaine + 0.5 µg/mL sufentanil at 37°C (warmed group) or 22°C (room-temperature group). Epidurals were placed at L3-L4 with a test dose of 3 mL of 1.5% lidocaine at room temperature, followed by programmed bolus epidural analgesia (initial 10 mL, 10 mL/h) and patient-controlled epidural analgesia (PCEA) 5 mL (30-minute lockout). Tympanic temperature was measured every 30 minutes from epidural initiation to delivery, defining intrapartum fever as ≥38°C. The primary outcome was fever incidence, on which the power analysis was based, and also maximum temperature and shivering. Secondary outcomes comprised analgesia onset, block level, labor durations, neonatal Apgar scores, umbilical cord blood pH and BE, and maternal adverse events. A total of 220 parturients were included (warmed group, n = 110; room-temperature group, n = 110). The warmed group had a lower intrapartum fever incidence (15.5% [17/110] vs 30.9% [34/110], relative risk [RR] 0.5 [95% confidence interval {CI}, 0.298-0.840]; P = .007); however, the reduction of 49.8% did not reach the preset clinically meaningful difference of 60% reduction proposed in the power analysis. The maximum body temperature was also lower in the warmed group: median (interquartile range [IQR]) 37.4 (IQR, 37.2-37.7) °C vs 37.6 (IQR, 37.3-38.0) °C, median difference -0.2 (95% CI, -0.3 to -0.1) °C (P = .006). Shivering incidence was not different between groups (10.9% [12/110] vs 14.5% [16/110]; P = .418). No statistically significant differences were observed between groups in any of the secondary outcomes assessed, including block characteristics, local anesthetic consumption, labor duration, neonatal outcomes, and maternal adverse events. Although we found a 50% reduction in the incidence of temperature rise using warmed (37°C) local anesthetics for epidural labor analgesia, this did not reach our preset threshold of 60% reduction.

Postpartum depression (PPD) is a prevalent mood disorder affecting 10-20% of women and represents a major contributor to maternal and infant morbidity. Labor pain, delivery mode, and anesthetic technique have been proposed as potential modifiers of postpartum psychological outcomes. Neuraxial anesthesia including epidural, spinal, and combined spinal-epidural techniques is the standard of care for labor analgesia and cesarean delivery, yet its association with PPD remains incompletely defined. This narrative review synthesizes current evidence evaluating the relationship between neuraxial anesthesia and dural puncture epidural (DPE) during vaginal and cesarean delivery and subsequent risk of postpartum depression. Across observational studies, cohort analyses, systematic reviews, and meta-analyses, neuraxial anesthesia does not appear to increase the risk of PPD at the population level. Many studies demonstrate a neutral association, while select analyses suggest modest protective effects, particularly among women experiencing severe labor pain or high intrapartum stress. Proposed mechanisms include attenuation of physiologic stress responses, improved pain control, and enhanced maternal satisfaction. These effects, however, are inconsistent across patient populations, and neuraxial anesthesia does not independently prevent PPD. In contrast, general anesthesia for cesarean delivery is consistently associated with higher rates of severe postpartum depression. Overall, postpartum depression is multifactorial condition in which anesthetic technique functions as a modifying rather than determining factor. Optimizing intrapartum pain management, minimizing unnecessary general anesthesia exposure, and implementing systematic postpartum mental health screening are essential components of comprehensive perinatal care.

Accurate identification of the epidural space is critical for procedures such as labor analgesia, postoperative pain management, and epidural steroid injections. The current loss-of-resistance (LOR) technique depends on subtle tactile cues, which are highly subjective and prone to variability and complications. The objective was to develop and evaluate a prototype device (EpiduraFlow) that provides real-time quantitative feedback using pressure and flow metrics to enhance the accuracy and reliability of epidural space identification. A prototype system was designed incorporating a piezoelectric micropump, differential pressure sensors, and a microcontroller with LCD display. The device infused saline at a controlled rate through a Tuohy epidural needle, continuously recording flow and pressure. Testing was performed on a validated epidural simulation model at the UCSD Health SimCenter. Flow and pressure changes were analyzed during needle advancement across simulated tissue layers. Mean flow rate during advancement through simulated soft tissue and ligaments layers was 1.02 ± 0.84 µl s-1, compared with 29.7 ± 5.3 µl s-1upon entry into the simulated epidural space (p≪0.001). Pressure dropped correspondingly at the moment of entry, and changes were displayed in real time on the LCD. Calibration of sensors against a manometer demonstrated high linearity (R2>0.98). EpiduraFlow reliably identified transitions into the epidural space during simulated procedures. This proof-of-concept demonstrates the feasibility of objective, quantitative epidural localization and supports further development toward handheld, sterile-compatible designs and preclinical validation.

Development and validation of a multivariable logistic regression model for predicting epidural-related maternal fever during labor analgesia: A retrospective cohort study.

Introduction: Regional analgesia is widely used for labour pain relief. The impact on foetal heart rates has been extensively studied, but little is known about its impact on neonatal heart rates. The aim of this study was to assess whether maternal use of epidural, spinal, or pudendal labour analgesia was associated with differences in neonatal heart rates. Methods: This Norwegian observational study included 1,281 singleton cephalic term vaginal deliveries from September 1, 2019, to June 30, 2021. Neonatal heart rates were measured using dry electrode technology. Generalised linear models adjusted for covariates related to the mother, neonate, and labour process were used to estimate neonatal heart rates by methods of maternal analgesia at 30 s, 1, 2, and 3 min after birth. The results were compared to a baseline representing heart rates modelled for infants whose mothers received no analgesia. Results: The median heart rate in all groups, including the epidural (n = 439), spinal (n = 34), pudendal (n = 36), and no analgesia (n = 772) groups, ranged from 147 to 175 beats per minute (bpm) at all time points. Infants whose mother received epidural analgesia had slightly higher mean heart rate compared to the baseline at 2 (167 vs. 164 bpm) and 3 (152 vs. 149 bpm) minutes of life (p < 0.05). No significant association was observed between spinal or pudendal analgesia and neonatal heart rates. Conclusion: Infants whose mothers received epidural labour analgesia had statistically, but not clinically significant, higher heart rates in the first minutes of life.

Epidural analgesia (EA) is a commonly employed and effective technique of providing pain relief during labor. Transcutaneous electrical acupoint stimulation (TEAS) is a cost-effective and safe non-pharmacological option for pain relief, but it has not previously been studied as an adjunct to EA. This study was designed to evaluate the efficacy of TEAS as an adjunctive therapy in patients undergoing epidural labor analgesia. In this study, 70 full-term primiparous women were randomly divided into two groups of 35. The TEAS group received true TEAS on specific acupoints, while the sham TEAS group received sham treatment. Both groups received a continuous epidural infusion of 0.1% ropivacaine and 0.5 μg/mL sufentanil at 10 mL/h for labor EA, with patient-controlled epidural analgesia (PCEA) boluses of 5 mL and a lockout interval of 15 minutes. The primary outcome was hourly mean consumption of the ropivacaine and sufentanil mixture. The mean drug consumption per hour was significantly lower in the TEAS group compared to the sham TEAS group (9.5±0.6 mL/h vs. 11.3±1.3 mL/h, P<0.001). The requirement for oxytocin was also significantly lower in the TEAS group compared to the sham TEAS group (11.4% vs. 31.4%, P=0.041). The incidence of pruritus was lower in the TEAS group compared to the sham TEAS group (0.0% vs. 17.1%, P=0.033). TEAS is a safe and effective non-pharmacological adjuvant for epidural labor analgesia.

Epidural analgesia has become a cornerstone in pain management during labor, offering effective relief while allowing the mother to remain conscious and actively participate in the birthing process. In obstetrics practice, the use of epidural techniques has evolved to enhance maternal comfort, improve labor experience, and facilitate smoother delivery outcomes. Various methods of epidural analgesia have been developed, each with distinct procedural approaches, benefits, and potential risks. Understanding these different techniques is essential for midwives and obstetric teams to tailor pain management strategies to individual patient needs. Pain during labor is a significant concern for many women, affecting their physical comfort, emotional well-being, and overall childbirth experience. Unmanaged or inadequately controlled pain can lead to increased stress, fatigue, and even adverse physiological responses that can complicate labor progress. Effective pain management not only enhances maternal satisfaction but also contributes to better labor outcomes and reduces the likelihood of interventions such as cesarean sections. Consequently, exploring optimal methods of analgesia, particularly epidural techniques, remains a priority in obstetrics and obstetric care. This review aims to systematically compare the various epidural analgesia methods used in obstetric practice, focusing on their efficacy, safety profiles, and impact on labor progression. By investigating different techniques such as dural puncture epidural, standard epidural, and combined spinal-epidural approaches, the research seeks to identify the most effective and safest options for pain relief during labor. The findings intend to inform clinical decision-making, optimize patient outcomes, and guide best practices in the administration of epidural analgesia for painless delivery.

Effective pain management during labor must balance adequate maternal pain relief with preservation of maternal participation and fetal safety. Epidural anesthesia remains the gold standard for labor analgesia. However, commonly used local anesthetics and opioid adjuvants are associated with adverse effects that include nausea, pruritus, urinary retention, and prolonged labor. Dexmedetomidine, a highly selective α2 agonist, does not carry the same risks for misuse and abuse as opioids do and may be a promising non-opioid adjuvant for epidural labor analgesia due to its analgesic, anxiolytic, and opioid-sparing properties. Furthermore, dexmedetomidine has unique pharmacodynamic effects, including preserving maternal consciousness while providing adequate analgesia. This combination of consciousness preservation and sufficient analgesia suggests dexmedetomidine may be a promising pharmaceutic for epidural anesthesia. In addition to preserving maternal consciousness, dexmedetomidine does not appear to cause a clinically significant increase in the motor blockade. Although epidural analgesia is known to prolong labor in nulliparous and multiparous patients, the use of dexmedetomidine as an epidural adjuvant does not have a significant effect on labor duration in available trials. Across studies, dexmedetomidine does not have deleterious outcomes for neonates, measured using the neonatal Apgar score. Although dexmedetomidine is not currently FDA-approved for epidural labor analgesia, existing evidence from available trials suggests its safety and efficacy as an opioid-sparing adjuvant. This narrative review aims to highlight the current state of knowledge of dexmedetomidine's pharmacology, efficacy, analgesic ability, and side effects.

Neuraxial block failure in obese parturients is a significant clinical challenge, leading to inadequate pain relief and increased maternal risk. Novel techniques such as the Combined Spinal-Epidural (CSE) and Dural Puncture Epidural (DPE) have emerged as promising alternatives to standard epidural, but their comparative efficacy and safety have not been systematically evaluated in a comprehensive network. This systematic review and network meta-analysis aimed to determine the optimal neuraxial technique for preventing analgesia and anesthesia failure in obese parturients, with specific attention to morbidly obese subgroups and procedural efficiency. Following Preferred Reporting Items for a Systematic Review and Meta-analysis (PRISMA) guidelines, we systematically searched PubMed, Embase, the Cochrane Library, and Web of Science for relevant studies published up to October 2025. We included randomized controlled trials (RCTs) that evaluated different neuraxial techniques in adult obese parturients (Body Mass Index ≥ 30kg/m²). The methodological quality was assessed using the Cochrane Risk of Bias 2 tool. A frequentist random-effects network meta-analysis was used to calculate pooled Odds Ratios (ORs) and their 95% Confidence Intervals (CIs). The hierarchy of interventions was determined by P-scores. Eleven RCTs comprising a total of 1,178 patients were included in the final analysis. For the primary outcome of preventing block failure, CSE ranked highest (P-score 0.88), followed by DPE (P-score 0.74). Compared with the standard epidural technique, both CSE (Odds Ratio [OR] 0.41; 95% CI 0.19-0.93) and DPE (OR 0.50; 95% CI 0.31-0.82) significantly reduced the risk of failure. In the subgroup analysis of morbidly obese parturients (BMI ≥ 40kg/m²), DPE and CSE remained the top-ranked interventions. Regarding safety, CSE was associated with a higher risk of hypotension compared to standard epidural, while DPE showed a comparable safety profile. Procedure times were generally similar across techniques, though heterogeneity existed. CSE and DPE appear to be the most effective neuraxial techniques for preventing block failure in obese parturients. While CSE ranks highest in efficacy, it carries an increased risk of hypotension. DPE offers a favorable balance of high efficacy and safety, particularly in morbidly obese populations. The choice of technique represents a clinical trade-off, where DPE may offer a more balanced efficacy and safety profile for labor analgesia. The optimal technique for cesarean delivery in this high-risk population remains uncertain due to a lack of direct comparative evidence, highlighting a critical area for future research. The protocol for this systematic review was prospectively registered with the International Prospective Register of Systematic Reviews (PROSPERO), registration number CRD420251244336.

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. A systematic search of PubMed, EMBASE, and the Cochrane Library (1985-2025) was conducted following PRISMA guidelines. Eligible studies included laboring women aged ≥ 18years 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. 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. 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.

Chlorhexidine is the preferred antiseptic for skin preparation owing to its superior antimicrobial efficacy compared with povidone-iodine. However, its supposed neurotoxicity-particularly in combination with alcohol-can cause catastrophic damage if inadvertently introduced into the neuraxial space during epidural or spinal anesthesia. We describe a fatal case of arachnoiditis following unintentional intradural injection of alcohol-based chlorhexidine during epidural catheter placement for labor analgesia and report a literature review. Among 114 records, five case reports met the inclusion criteria. All patients were women receiving epidural or spinal anesthesia for obstetric or surgical procedures. Exposure involved either direct injection or contamination of anesthetic solutions with chlorhexidine. Onset ranged from immediate lumbar pain to delayed neurological deterioration. Reported outcomes included paraplegia, tetraplegia, hydrocephalus, syringomyelia, and profound functional loss. Therapeutic interventions-corticosteroids, neurosurgery, cerebrospinal fluid shunting, and analgesia-were ineffective in reversing deficits. Error prevention is essential and relies on the use of colored solutions, strict physical separation between chlorhexidine and other solutions used during procedures, the use of pre-impregnated applicators, or alternatively the use of naturally colored povidone-iodine, which may be less neurotoxic. Accidental intradural or epidural administration of chlorhexidine is a rare but devastating event most often associated with poor outcomes. Prevention requires mandating colored antiseptics or enforcing strict handling protocols.

Awareness, attitude, and anticipated willingness to use labor analgesia: a single-center antenatal survey study from a tertiary referral center in Saudi Arabia (2024).

Median effective dose (ED50) of intrathecal ropivacaine for labor analgesia initiation in nulliparous vs. multiparous women: an up-down sequential allocation study.