Socio-economic disadvantage and utilisation of labour epidural analgesia in Scotland: a population-based study†.

Socio-economic deprivation is associated with adverse maternal and childhood outcomes. Epidural analgesia, the gold standard for labour analgesia, may improve maternal well-being. We assessed the association of socio-economic status with utilisation of epidural analgesia and whether this differed when epidural analgesia was advisable for maternal safety. This was a population-based study of NHS data for all women in labour in Scotland between 1 January 2007 and 23 October 2020, excluding elective caesarean sections. Socio-economic status deciles were defined using the Scottish Index of Multiple Deprivation. Medical conditions for which epidural analgesia is advisable for maternal safety (medical indications) and contraindications were defined according to national guidelines. Of 593,230 patients in labour, 131,521 (22.2%) received epidural analgesia. Those from the most deprived areas were 16% less likely to receive epidural analgesia than the most affluent (relative risk 0.84 [95%CI 0.82-0.85]), with the inter-decile mean change in receiving epidural analgesia estimated at -2% ([95%CI -2.2% to -1.7%]). Among the 21,219 deliveries with a documented medical indication for epidural analgesia, the socio-economic gradient persisted (relative risk 0.79 [95%CI 0.75-0.84], inter-decile mean change in receiving epidural analgesia -2.5% [95%CI -3.1% to -2.0%]). Women in the most deprived areas with a medical indication for epidural analgesia were still less likely (absolute risk 0.23 [95%CI 0.22-0.24]) to receive epidural analgesia than women from the most advantaged decile without a medical indication (absolute risk 0.25 [95%CI 0.24-0.25]). Socio-economic deprivation is associated with lower utilisation of epidural analgesia, even when epidural analgesia is advisable for maternal safety. Ensuring equitable access to an intervention that alleviates pain and potentially reduces adverse outcomes is crucial.

Education Program Regarding Labor Epidurals Increases Utilization by Hispanic Medicaid Beneficiaries: A Randomized Controlled Trial.

BACKGROUND: Hispanic women choose epidural labor analgesia less commonly than non-Hispanic women. This may represent a healthcare disparity related to a language barrier and inadequate opportunities for labor analgesia education. It was hypothesized that a language-concordant, educational program regarding labor epidurals would improve epidural utilization in two independent cohorts of Hispanic and non-Hispanic women. METHODS: A randomized controlled trial, blinded to anesthesia, nursing, and obstetric providers, was completed at an academic hospital (February 2015 to February 2017). Two cohorts of Medicaid beneficiaries of Hispanic (English- and/or Spanish-speaking) and non-Hispanic ethnicity were enrolled concurrently. The patients were randomized to routine care alone or routine care and an additional educational program comprised of three components: a video show, corresponding pamphlet, and in-person counseling. The primary endpoint was use of epidural labor analgesia. The secondary endpoint was change in response before and after delivery on common misconceptions based on a 12-point epidural questionnaire. RESULTS: Hispanic women randomized to the intervention group were 33% more likely to choose epidural analgesia compared to the routine care group (40 of 50 [80%] vs. 30 of 50 [60%]; risk ratio, 1.33 [95% CI, 1.02 to 1.74]; P = 0.029). For the non-Hispanic cohort, no difference was detected in epidural use between the intervention and routine care groups (41 of 50 [82%] vs. 42 of 49 [86%]; risk ratio, 0.96 [95% CI, 0.80 to 1.14]; P = 0.62), but the study was underpowered to determine a result of no difference. Patients assigned to the intervention had a greater improvement in epidural understanding compared with routine care, among both Hispanic (2.26 vs. 0.74, respectively; difference in change from baseline, 1.52 [95% CI, 0.77 to 2.27]; P < 0.001) and non-Hispanic (1.36 vs. 0.33, respectively; difference in change from baseline, 1.03 [95% CI, 0.23 to 1.75]; P = 0.005) cohorts. There were no adverse events during the trial. CONCLUSIONS: The educational program increased epidural use among Hispanic women. The educational program reduced misconceptions regarding epidural analgesia in both Hispanic and non-Hispanic cohorts.

Implementation of an Evidence-Based Practice Change to Offer Nitrous Oxide During Labor.

OBJECTIVE: The aim of this evidence-based practice change was to implement use of nitrous oxide as a pain management option during labor and to examine women's satisfaction with that option. DESIGN: Evidence-based practice change guided by the model for evidence-based practice change. SETTING: Labor and delivery unit in a tertiary medical center in the southwestern United States. PARTICIPANTS: Laboring women who met eligibility criteria were offered the option of nitrous oxide during a 2-month period. MEASUREMENTS: Process indicators to measure compliance with the practice change among staff, uptake of nitrous oxide among women, and women's satisfaction with the choice to use nitrous oxide. RESULTS: Nitrous oxide was offered to 26% (n = 55) of eligible women. Most of the 55 women who used nitrous oxide during the implementation period reported satisfaction with it and indicated that they would consider nitrous oxide for a future labor. CONCLUSION: Our experience implementing a practice change to offer nitrous oxide to laboring women indicated that use of nitrous oxide was feasible in this setting and that women were receptive to this option, were satisfied with its use, and would use nitrous oxide for a future labor.

An economic analysis of patient controlled remifentanil and epidural analgesia as pain relief in labour (RAVEL trial); a randomised controlled trial.

OBJECTIVE: To compare the costs of a strategy of patient controlled remifentanil versus epidural analgesia for pain relief in labour. DESIGN: We performed a multicentre randomised controlled trial in 15 hospitals in the Netherlands, the RAVEL trial. Costs were analysed from a health care perspective alongside the RAVEL trial. POPULATION: Pregnant women of intermediate to high risk beyond 32 weeks gestation who planned vaginal delivery. METHODS: Women were randomised before the onset of labour, to receive either patient controlled remifentanil or epidural analgesia when pain relief was requested during labour. MAIN OUTCOME MEASURES: Primary outcome for effectiveness was satisfaction with pain relief, expressed as the area under the curve (AUC). A higher AUC represents higher satisfaction with pain relief. Here, we present an economic analysis from a health care perspective including costs from the start of labour to ten days postpartum. Health-care utilization was documented in the Case Report Forms and by administering an additional questionnaire. RESULTS: The costs in the patient controlled remifentanil group (n = 687) and in the epidural group (n = 671) were €2900 versus €3185 respectively (mean difference of -€282 (95% CI -€611 to €47)). The (non-significant) higher costs in the epidural analgesia group could be mainly attributed to higher costs of neonatal admission. CONCLUSION: From an economic perspective, there is no preferential pain treatment in labouring intermediate to high risk women. Since patient controlled remifentanil is not equivalent to epidural analgesia with respect to AUC for satisfaction with pain relief we recommend epidural analgesia as the method of choice. However, if appropriately counselled on effect and side effects there is, from an economic perspective, no reason to deny women patient controlled remifentanil.

Primary Spoken Language and Neuraxial Labor Analgesia Use Among Hispanic Medicaid Recipients.

BACKGROUND: Hispanic women are less likely than non-Hispanic Caucasian women to use neuraxial labor analgesia. It is unknown whether there is a disparity in anticipated or actual use of neuraxial labor analgesia among Hispanic women based on primary language (English versus Spanish). METHODS: In this 3-year retrospective, single-institution, cross-sectional study, we extracted electronic medical record data on Hispanic nulliparous with vaginal deliveries who were insured by Medicaid. On admission, patients self-identified their primary language and anticipated analgesic use for labor. Extracted data included age, marital status, labor type, delivery provider (obstetrician or midwife), and anticipated and actual analgesic use. Household income was estimated from census data geocoded by zip code. Multivariable logistic regression models were estimated for anticipated and actual neuraxial analgesia use. RESULTS: Among 932 Hispanic women, 182 were self-identified as primary Spanish speakers. Spanish-speaking Hispanic women were less likely to anticipate and use neuraxial anesthesia than English-speaking women. After controlling for confounders, there was an association between primary language and anticipated neuraxial analgesia use (adjusted relative risk: Spanish- versus English-speaking women, 0.70; 97.5% confidence interval, 0.53-0.92). Similarly, there was an association between language and neuraxial analgesia use (adjusted relative risk: Spanish- versus English-speaking women 0.88; 97.5% confidence interval, 0.78-0.99). The use of a midwife compared with an obstetrician also decreased the likelihood of both anticipating and using neuraxial analgesia. CONCLUSIONS: A language-based disparity was found in neuraxial labor analgesia use. It is possible that there are communication barriers in knowledge or understanding of analgesic options. Further research is necessary to determine the cause of this association.

Continuous assessment of labour pain using handgrip force.

BACKGROUND: Assessment of dynamic changes in painful experiences, such as labour, using conventional rating scales (eg, numerical rating scale [NRS]) has limitations. An alternative for continuous pain evaluation could be a signal generated by voluntary action of the parturient. Remifentanil administration for obstetric analgesia could be improved by these dynamic measures of labour pain. In the present study, handgrip force was measured by a dynamometer to signal labour pain. OBJECTIVES: To evaluate: whether continuous monitoring of labour pain using handgrip force allows for determination of pain measurement during contractions; and the correlation between handgrip force and pain intensity on NRS. METHODS: The present observational, single-centre study included 43 parturients. After calibration of the dynamometer for individual hand muscle strength, pain was recorded during early and late labour using a dynamometer and an NRS. The primary end point was the correlation coefficient between NRS ratings and peak intensity recorded by the dynamometer. RESULTS: All dynamometer-registered readings were also registered by the external tocogram. All contractions recorded by external tocogram were also registered by the dynamometer. Handgrip force was moderately correlated with pain scores on the NRS. Mean handgrip force during contractions had the highest correlation coefficient (Pearson's r=0.67) compared with peak handgrip force (r=0.56) and area under the curve of handgrip force (r=0.55). CONCLUSIONS: Pain intensity and duration can be assessed continuously using handgrip force measured via a dynamometer. The feedback of intensity and duration of pain could optimize patient-controlled remifentantil application for obstetric analgesia and other situations of highly variable pain intensity.

Maternal microcirculation and sidestream dark field imaging: a prospective assessment of the association between labour pain and analgesia on the microcirculation of pregnant women.

BACKGROUND: Pregnancy places significant demands on the cardiovascular system leading to measurable changes in the macrocirculation and potentially the microcirculation. During labour, both uterine contractions and labour pain can further impact cardiovascular status. The objective of this observational study was to compare sublingual microcirculation in labouring parturients before and after epidural analgesia. METHODS: Healthy pregnant, labouring women requesting epidural analgesia were approached to participate. Participants with cardiovascular disease, diabetes, obesity, smoking or caffeine intake were excluded. The sidestream dark field device was applied to the sublingual mucosa obtaining images of at least 20 seconds in 5 visual fields before and after epidural analgesia. Video clips were analyzed randomly and blindly. The primary outcome was mean microvascular flow index (MFI). RESULTS: Twelve participants completed this study. The results demonstrate no statistically significant difference in the MFI during labour pain (2.9±0.1) compared to after epidural analgesia (3.0±0.04, p = 0.31). Furthermore, there were no statistically significant differences in any secondary outcomes. CONCLUSION: Our findings indicate that epidural analgesia may not impact sublingual microcirculation in labouring women. This agrees with literature supporting epidural analgesia as a safe, appropriate method of pain relief during labour with limited impact on peripheral macro or microcirculation.

Comparison of the PainMatcher and the Visual Analogue Scale for assessment of labour pain following administered pain relief treatment.

OBJECTIVE: during childbirth, it is necessary to assess and monitor experienced pain and to evaluate the effect of pain relief treatment. The aim of this study was to compare the PainMatcher (PM) with the Visual Analogue Scale (VAS) for the assessment of labour pain and the effect of pain relief treatment. DESIGN: randomised controlled trial. SETTING: labour ward with approximately 2500 childbirths per year in western Sweden. PARTICIPANTS: 57 women with labour pain treated with acupuncture or sterile water injections scored their electrical pain threshold and pain intensity with the PM. Pain intensity was also assessed with the VAS. Electrical pain threshold and pain intensity were assessed immediately after a uterine contraction before and 30, 60, 90, 120, 150 and 180 minutes after treatment. MEASUREMENTS AND FINDINGS: the results showed a weak correlation (r=0.13, p<0.05) between the pain intensity scores on the PM and the VAS. The PM detected changes (decrease) in pain intensity to a lower degree than the VAS. Surprisingly, in over 10% of sessions, women scored their pain intensity during a uterine contraction lower than their electrical pain threshold with the PM. However, electrical pain thresholds with the PM correlated well throughout all measurements. CONCLUSIONS: the PM is a reliable tool for the assessment of electrical pain threshold; however, the VAS is more sensitive than the PM for recording changes in pain intensity when assessing the effects of treatment on labour pain. IMPLICATIONS FOR PRACTICE: the PM and the VAS are not interchangeable in the case of labour pain, and there is still a need for research in this area to find a more suitable assessment instrument for the evaluation of labour pain.

Focused review: ropivacaine versus bupivacaine for epidural labor analgesia.

Neuraxial analgesia is frequently administered to women in labor. For many years, bupivacaine has been used because of its long duration of action, lack of excessive motor block, and minimal fetal and neonatal effects. However, bupivacaine is one of the most cardiotoxic local anesthetics in current use and motor block is still a problem. Many local anesthetics such as bupivacaine exist in 2 forms, levorotatory and dextrorotatory. Ropivacaine, an amide local anesthetic produced in the pure levorotatory form addresses some of the concerns related to bupivacaine. In this article, we present the literature comparing ropivacaine and bupivacaine to determine whether there is an advantage to using one of these local anesthetics for labor analgesia. We found that there is no advantage to the routine use of ropivacaine for labor analgesia.

Promoting epidural analgesia for labor: 2005-2007 diffusion in Lombardia, Italy.

BACKGROUND: Since January 2005 the Regional Government of Lombardia, a large Italian region with over 1/5 of all Italian births, allocated public funds for 3 consecutive years to help provide epidural analgesia (EA) for women in labor. The aim of the present study was to evaluate the trend of diffusion of EA in the triennium 2005-2007. METHODS: Data obtained from regional Obstetric Departments, recognized by the National Health Care System, were elaborated by the Epidemiological Service of Regione Lombardia. The software looked for specific codes for vaginal deliveries, with or without EA, and Cesarean sections included in the administrative patient records. RESULTS: A substantial increase in epidurals administered in comparison to total vaginal deliveries was recorded after assignment of regional financing: from 8.2% in 2005, to 10.4% in 2006 and 12.9% in 2007 (P<0.0001). More than 60% of epidurals were performed in 8 hospitals with >2 000 births per year. The rate of EAs in these hospitals was 18% in 2005, 22% in 2006 and 24.9% in 2007. In the 69 hospitals with <2000 births per year, the rate of EAs was markedly lower: 4% in 2005, 5.5% in 2006 and 7.8% in 2007. In both cases, the increase was statistically significant (P<0.0001). At the three-year time-point, the rate of Cesarean sections did not change. CONCLUSIONS: The continuous increase of EA for labor after regional financings suggests that the low rate of pain relief procedures in Lombardia was mainly due to economic and organizational issues, rather than to cultural and psychological factors.

Assessment of behavior during labor in rats and effect of intrathecal morphine.

BACKGROUND: Efficacy of analgesics varies with the type of pain. Little is known in this regard concerning labor pain, given the ethical barriers to study in humans and the lack of surrogate animal models. To address this, the authors classified and quantified spontaneous behaviors during labor and delivery in rats and examined the effects of a known analgesic, intrathecal morphine. METHODS: Pregnant rats were video recorded for 72 h surrounding the time of anticipated labor and delivery. Specific behaviors were identified and classified into general activities, phasic stretching behaviors, and maternal attention activities. Rats received intrathecal infusion of saline or morphine, 0.035-3.5 microg/h, beginning approximately 1 day before delivery, and effects on behaviors and response to noxious heating of the paw were quantified. RESULTS: Phasic stretching behaviors occurred with high frequency before delivery of the first pup and were rare after delivery of the last pup. Intrathecal morphine at infusion rates greater than 0.035 microg/h abolished these behaviors without affecting general or maternal behaviors or the timing or duration of labor and delivery. Morphine was also antinociceptive to noxious heat, but only at infusion rates of 1.0 microg/h or higher. CONCLUSIONS: Phasic stretching behaviors are observed after distension or inflammation of pelvic viscera in rats, and similar behaviors occur during labor and delivery. Selective and dose-related blockade by intrathecal morphine of only these behaviors suggests that they reflect nociception and that this simple monitoring method can be used to study therapies for the pain of labor and delivery.

The development and validation of a dynamic model to account for the progress of labor in the assessment of pain.

BACKGROUND: Labor pain is often described as the worst pain in a woman's life, but the experience is highly variable. Although many factors have been linked to labor pain, it has been difficult to assess the individual effects of these factors because labor is a dynamic process and pain intensity changes over the course of labor. Previous studies have used average pain scores. The aim of this study was to develop and validate a model that would allow for the statistical analysis of factors that affect pain throughout labor. METHODS: We conducted this study with a retrospective database drawn from the medical records of 200 consecutive nulliparous parturients who delivered at New York Presbyterian Hospital between October 2006 and January 2007. Numerical rating scale scores for pain with contractions (0-10 scale), cervical dilation, and oxytocin use before analgesia request were recorded. Nonlinear effects modeling with a sigmoid equation was used to describe the relationship between reported pain and cervical dilation. The modeling technique was developed with data from 91 parturients and validated with an independent set of 95 parturients (all parturients with pain scores more than zero). The resulting model was used to analyze the effect of a sample covariate, oxytocin administration, on reported pain in the entire data set. RESULTS: The model derived from our training set was predictive of the data from our validation set (P < 0.001). Predicted pain scores were on average two numerical rating scale points above or below measured pain scores. Analyzing oxytocin as a covariant showed that women treated with oxytocin reported 48% more pain at the start of labor but did not have a significantly more rapid increase in pain or higher maximal pain when compared with women not treated with oxytocin. Women treated with oxytocin had slower early labor and more rapid late labor. CONCLUSION: We have developed and validated a model for describing pain over the course of labor. Our model is suited to the statistical analysis of covariance and could potentially be used to compare the effects of covariants on labor pain and the rate of change of pain.

Decision analysis for epidural labor analgesia with Multiattribute Utility (MAU) model.

OBJECTIVES: Epidural analgesia (EA) is an effective and safe method to relieve labor pain. Little is known about the factors associated with decision on EA. We applied Multiattribute Utility (MAU) theory to ascertain possible factors on which we based to predict whether parturients would receive EA or not (non-EA) during their labor. METHODS: A hierarchical questionnaire on the basis of MAU theory was designed by experts to include individual attributes, knowledge and attitude toward EA and cue factors. Items in the questionnaire were compared between the EA and the non-EA groups. Receiver operating characteristics curve was used to assess predictive validity of the MAU model. RESULTS: Of 167 parturients responding to the questionnaire, 151 participants (75 EA and 76 non-EA groups) completed all questions. Parturients in the EA group had significantly higher education level (rate of junior college or above: 88% vs. 67%, P=0.002). There were also more primiparae in the EA group compared with non-EA group (76% vs. 46%, P<0.001). For items in MAU model, 12 out of 20 items revealed significant differences between the 2 groups. Among them, "fear of side effects," "fear of severe complications," and "fear of needle" had the most remarkable differences. The area under receiver operating characteristics equaled to 0.91 (95% confidence interval=0.86, 0.96) for pre-labor decision and 0.83 (95% confidence interval=0.76, 0.89) for final decision. DISCUSSION: These findings suggest that our MAU model can predict pre-labor decision and final decision of parturients by the incorporation of correlates with respect to knowledge and attitude.

Knowledge, attitude and use of labour pain relief methods among women attending antenatal clinic in Nairobi.

BACKGROUND: Labour analgesia has rapidly gained popularity in obstetric practice. Low usage in the developing world has raised concern. OBJECTIVES: To assess the knowledge, attitude and use of labour pain relief methods in women attending antenatal clinic in Nairobi. DESIGN: A prospective study. SETTING: Aga Khan University Hospital, a teaching and referral hospital in Nairobi, Kenya. SUBJECTS: Two hundred and two consecutive expectant mothers attending antenatal clinic at the Aga Khan University Hospital, Nairobi. RESULTS: Fifty six per cent of the participants had knowledge about labour pain relief methods. Friends, the antenatal clinic and books/leaflets were the major source on information. Ninety per cent indicated they would intend to have some form of labour pain relief at their next delivery. Eighteen percent had been offered some form of pain relief at their last delivery with 82% of those offered having effective pain relief (P < 0.001). CONCLUSIONS: While most of our participants were well educated, level of knowledge of labour analgesia is still low. Use of labour analgesia is also still quite low in comparison to the western World. It is recommended that obstetricians and anaesthetists participate in knowledge dissemination and setup of dedicated labour analgesia services in this region.

[Anxiety assessment in parturients requesting epidural analgesia for pain relief]. / Ocena leku u rodzacych zdecydowanych na analgezje zewnatrzoponowa.

OBJECTIVES: Neuraxial methods provide the most effective labor pain relief. This study aimed at assessing anxiety level in parturients requesting epidural analgesia (EA). MATERIAL AND METHODS: Forty five women in spontaneous, active labor were enrolled, both primiparas (n=36) and multiparas (n=9). Anxiety was assessed by means of Spielberger State and Trait Anxiety Inventory (STAI) before administration of EA, and pain was measured by visual-analog scale (VAS) before and after analgesia. RESULTS: In all the studied parturients state anxiety was strikingly higher than the trait (53.9 +/- 11.8 vs. 39.3 +/- 8.4; P < 0.0001); the difference appeared insignificant in multiparas only. State anxiety was comparable independently of parity, labor outcome and systemic opioid administration. No association between anxiety level and labor pain intensity preceding analgesia, the duration of labor stages and demographic parameters could be found. However, a negative correlation between state anxiety and pain intensity reported after EA administration was noted (R = -0.315, p = 0.040), and, in cases of physiological labor, a negative association between state anxiety and the neonate Apgar score at the 1st minute after birth could be observed (R = -0.337, p = 0.047, Spearman rank test). CONCLUSIONS: In parturients requesting EA, state anxiety level is increased and not connected with the trait. Furthermore, in these women, anxiety appears not to be associated with labor pain but may influence the analgesic effect of the blockade. Anxiety does not determine labor duration and outcome; however, it may be connected with the well-being of the neonate immediately after birth.

[Knowledge and acceptance of obstetric peridural analgesia: survey of pregnant women in Togo]. / Niveau de connaissance et acceptabilité e l'analgésie péridurale: enquête auprès des femmes enceintes au Togo.

The purpose of this study was to evaluate knowledge and acceptance of obstetric peridural analgesia among pregnant women in Togo. A prospective, descriptive survey was carried out over a period of one month. A standardized survey form was used to collect data. A total of 303 pregnant women with a mean age of 27 +/- 6 years were interviewed. A proportion of primiparous and multiparous was the same, i.e., 50%. Among multiparous women, 83.5% described labor pain during previous deliveries as severe. Twelve percent of the pregnant women interviewed claimed knowledge of techniques to control labor pain. Three pregnant women reported a detailed understanding of peridural analgesia obtained from the Internet. A total of 253 women (83.5%) replied affirmatively when asked if they would opt for peridural analgesia if it was offered free of charge for delivery at the end of the current pregnancy. Acceptance was motivated by better delivery conditions for the newborn (112 women) and comfort achieved by pain relief (130 women). Refusal was motivated by a religious belief that painful delivery was in the natural order (31 women). Among the six Moslem women that refused painless delivery, two from the Djerma ethnic group stated that pain was the best expression of their femininity. The acceptance rate fell from 83.5% to 70% if peridural analgesia was offered at extra charge. Most pregnant women in Togo expressed interest in trying peridural analgesia. It is compulsory in medical indications.

A questionnaire survey on patients' attitudes towards epidural analgesia in labour.

OBJECTIVES: To evaluate patient attitudes about epidural services in labour and correlate them with patient options and actual usage of epidural analgesia. DESIGN: Questionnaire survey. SETTING: Eight Hospital Authority obstetrics units. PARTICIPANTS: A cohort of new antenatal patients and a cohort of postnatal in-patients over 1 calendar month. MAIN OUTCOME MEASURES: Antenatal patient awareness of epidural services and attitudes towards epidural analgesia during labour; the actual usage of such analgesia and the reported experience of postnatal patients. RESULTS: A total of 2109 and 2851 patients completed the antenatal and postnatal survey, respectively. The former revealed that only 47% of patients had been exposed to the concept of epidural analgesia in labour, and only 13% opted for such analgesia. In the postnatal cohort, the overall epidural analgesia rate was 10%, although 19% had actually requested it. Patients who received epidural analgesia in labour were more likely to consider their experience as favourable (85%) compared to those who went through labour without such analgesia (26%) [P<0.001]. There was no significant improvement in knowledge about epidural analgesia among postnatal as compared to antenatal patients. The main reasons generally ascribed by patients for not being able to obtain an epidural service despite it being requested, were related to limited resources. CONCLUSION: The results showed poor general awareness of pregnant women about the proper role of epidural analgesia in labour, leading to a low patient demand for such services. Despite the low prevailing request rate for epidural analgesia in labour, there appears to be a lack of adequate resources to meet the demand.

Quantile regression for longitudinal data using the asymmetric Laplace distribution.

In longitudinal studies, measurements of the same individuals are taken repeatedly through time. Often, the primary goal is to characterize the change in response over time and the factors that influence change. Factors can affect not only the location but also more generally the shape of the distribution of the response over time. To make inference about the shape of a population distribution, the widely popular mixed-effects regression, for example, would be inadequate, if the distribution is not approximately Gaussian. We propose a novel linear model for quantile regression (QR) that includes random effects in order to account for the dependence between serial observations on the same subject. The notion of QR is synonymous with robust analysis of the conditional distribution of the response variable. We present a likelihood-based approach to the estimation of the regression quantiles that uses the asymmetric Laplace density. In a simulation study, the proposed method had an advantage in terms of mean squared error of the QR estimator, when compared with the approach that considers penalized fixed effects. Following our strategy, a nearly optimal degree of shrinkage of the individual effects is automatically selected by the data and their likelihood. Also, our model appears to be a robust alternative to the mean regression with random effects when the location parameter of the conditional distribution of the response is of interest. We apply our model to a real data set which consists of self-reported amount of labor pain measurements taken on women repeatedly over time, whose distribution is characterized by skewness, and the significance of the parameters is evaluated by the likelihood ratio statistic.