Responsiveness to laboratory pain in women as a function of age and childbirth pain experience

The association between adverse childhood experiences and peripartal pain experience

ABSTRACT

Adverse childhood experiences (ACEs) are associated with altered ongoing and evoked pain experiences, which have scarcely been studied for the peripartum period. We aimed to investigate how ACEs affect pain experience in pregnancy and labor. For this noninterventional trial with a short-term follow-up, pregnant women were divided into a trauma group (TG) with ACEs (n = 84) and a control group (CG) without ACEs (n = 107) according to the Childhood Trauma Questionnaire. Pain experience in pregnancy and labor was recorded by self-report and the German Pain Perception Scale. Pain sensitivity prepartum and postpartum was assessed by Quantitative Sensory Testing and a paradigm of conditioned pain modulation (CPM), using pressure pain thresholds (PPTs) and a cold pressor test. The TG showed higher affective and sensory scores for back pain and a more than doubled prevalence of preexisting back pain. Pelvic pain differences were nonsignificant. The TG also exhibited increased affective scores (1.71 ± 0.15 vs 1.33 ± 0.11), but not sensory scores for labor pain during spontaneous delivery. There were no group differences in prepartum pain sensitivity. While PPTs increased through delivery in the CG (clinical CPM), and this PPT change was positively correlated with the experimental CPM (r = 0.55), this was not the case in the TG. The association of ACEs with increased peripartal pain affect and heightened risk for preexisting back pain suggest that such women deserve special care. The dissociation of impaired clinical CPM in women with ACEs and normal prepartum experimental CPM implies at least partly different mechanisms of these 2 manifestations of endogenous pain controls.

Association of Gender, Painkiller Use, and Experienced Pain with Pain-Related Fear and Anxiety among University Students According to the Fear of Pain Questionnaire-9

Anxiety and fear are determinants of acute and chronic pain. Effectively measuring fear associated with pain is critical for identifying individuals’ vulnerable to pain. This study aimed to assess fear of pain among students and evaluate factors associated with pain-related fear. We used the Fear of Pain Questionnaire-9 to measure this fear. We searched for factors associated with fear of pain: gender, size of the city where the subjects lived, subject of academic study, year of study, the greatest extent of experienced pain, frequency of painkiller use, presence of chronic or mental illness, and past hospitalization. We enrolled 717 participants. Median fear of minor pain was 5 (4–7) fear of medical pain 7 (5–9), fear of severe pain 10 (8–12), and overall fear of pain 22 (19–26). Fear of pain was associated with gender, frequency of painkiller use, and previously experienced pain intensity. We found a correlation between the greatest pain the participant can remember and fear of minor pain (r = 0.112), fear of medical pain (r = 0.116), and overall fear of pain (r = 0.133). Participants studying medicine had the lowest fear of minor pain while stomatology students had the lowest fear of medical pain. As students advanced in their studies, their fear of medical pain lowered. Addressing fear of pain according to sex of the patient, frequency of painkiller use, and greatest extent of experienced pain could ameliorate medical training and improve the quality of pain management in patients.

Prodrome and Non-prodrome Phenotypes of Bladder Pain Syndrome/Interstitial Cystitis

OBJECTIVE

To test the hypothesis that risk factors for bladder pain syndrome/interstitial cystitis (BPS/IC) in women differ between those with and without the BPS/IC prodrome.

MATERIALS AND METHODS

Incident cases of BPS/IC and healthy controls were recruited nationally. More than half the BPS/IC cases reported subsyndromal urinary symptoms for decades before onset of BPS/IC and were identified as having the prodrome. Risk factors for BPS/IC were examined separately for cases with and without the prodrome using a set of matched controls.

RESULTS

Two risk factors distinguished 178 prodrome from 134 non-prodrome cases. One was "UTIs" in the year before BPS/IC onset, possibly a manifestation of the prodrome itself. The other was the presence of the maximal number of nonbladder syndromes (NBSs): prodrome cases were 12 times more likely than non-prodrome cases to have ≥4 NBSs. Additional risk factors for prodrome and/or non-prodrome cases were the direct association of exogenous female hormones, as well as 3 inverse associations: type 2 diabetes mellitus, multiple pregnancies, and current daily smoking.

CONCLUSION

Prodrome cases developed urinary symptoms in their early 20s (ie, the prodrome) and were at very high risk of numerous NBSs. Non-prodrome cases developed urinary symptoms in their early 40s (ie, full-blown BPS/IC) and were no more likely than controls to have the maximal number of NBSs. These findings are consistent with recent suggestions of two BPS/IC phenotypes: one with systemic and psychosocial manifestations and the other more specific to the bladder. Additionally, several risk factors identified here might be hints of related or causal nervous system pathophysiologies.

Changes in birth-related pain perception impact of neurobiological and psycho-social factors

PURPOSE

To analyse post-partum short- and long-term pain sensitivity and the influence of endogenous pain inhibition as well as distinct psycho-social factors on birth-related pain.

METHODS

Pain sensitivity was assessed in 91 primiparous women at three times: 2-6 weeks before, one to 3 days as well as ten to 14 weeks after childbirth. Application of a pressure algometer in combination with a cold pressor test was utilised for measurement of pain sensitivity and assessment of conditioned pain modulation (CPM). Selected psycho-social factors (anxiety, social support, history of abuse, chronic pain and fear of childbirth) were evaluated with standardised questionnaires and their effect on pain processing then analysed.

RESULTS

Pressure pain threshold, cold pain threshold and cold pain tolerance increased significantly directly after birth (all p < 0.001). While cold pain parameters partly recovered on follow-up, pressure pain threshold remained increased above baseline (p < 0.001). These pain-modulating effects were not found for women with history of abuse. While CPM was not affected by birth, its extent correlated significantly (r = 0.367) with the drop in pain sensitivity following birth. Moreover, high trait anxiety predicted an attenuated reduction in pain sensitivity (r = 0.357), while there was no correlation with fear of childbirth, chronic pain and social support.

CONCLUSION

Pain sensitivity showed a decrease when comparing post-partum with prepartum values. The extent and direction of CPM appear to be a trait variable that predicted post-partum hypalgesia without being changed itself. Post-partum hypalgesia was reduced in women with a history of abuse and high trait anxiety, which suggests that individual differences in CPM affect childbirth experience.

A Novel Quantitative Pain Assessment Instrument That Provides Means of Comparing Patient's Pain Magnitude With a Measurement of Their Pain Tolerance

Background

Traditional pain assessment instruments are subjective in nature. They are limited to subjective reporting of the presence and magnitude of pain. There is no means of validating their response or assessing their pain tolerance. The objective of this study was to determine the potential value of a novel addition to the traditional physical examination concerning a patient’s pain and more importantly their pain tolerance.

Methods

Extensive preliminary data were collected on 359 consecutive private practice knee patients referable the subject’s pain, including the magnitude, the most pain ever experienced, and their opinion of personal pain tolerance. The novel evaluation included physical testing of a series of small ball drops through a vertical tube from various fixed levels on the index finger and patella. The patient’s response to this impact testing provided quantitative information, from which a comparison was made to their pain opinion and also to that of other patients with similar demographics.

Results

Nine percent of the patients rated their pain tolerance below the midpoint on the visual analog scale. Seventy-one percent thought they were above the midpoint on the scale in regards to pain tolerance. There were discrepancies in both directions between the subject’s opinion on pain tolerance and their rating of their pain experience to the ball drop testing. Twenty-eight percent of the entire patient group rated themselves above 5 on tolerance, but experienced above the average discomfort compared to other subjects reporting on the finger impact testing.

Conclusions

This report introduces a novel method for collecting data concerning pain that can be subjected to quantification. The database included quantitative measures providing the opportunity to confirm, validate or refute the patient’s assertions concerning pain magnitude and tolerance. This method is best described as a patient pain profile. It has the potential to give both the patient and the physician quantified objective information rendering insight not otherwise available.

Does severe acute pain provoke lasting changes in attentional and emotional mechanisms of pain-related processing? A longitudinal study

Pain experiences, learning, and genetic factors have been proposed to shape attentional and emotional processes related to pain. We aimed at investigating whether a singular major pain experience also changes cognitive-emotional processing. The influence of acute postoperative pain after cosmetic surgery of the thorax was tested in 80 preoperatively pain-free male individuals. Acute pain was measured as independent variable during the first week postsurgery by pain intensity ratings and the requested analgesic boluses (Patient-Controlled Epidural Analgesia (PCEA)). Pain catastrophizing (Pain Catastrophizing Scale (PCS)), pain anxiety (Pain Anxiety and Symptom Scale (PASS)), pain hypervigilance (Pain Vigilance and Awareness Questionnaire (PVAQ)), and attentional biases to emotionally loaded stimuli (including pain) in a dot-probe task were assessed 1 week, 3 months, and 6 months postsurgery as dependent variables. Hierarchical regression analyses were performed to test whether the 2 acute pain parameters can predict these cognitive-emotional variables. As a rigorous test, significant prediction was required in addition to the prediction of the dependent variables by themselves with lag-1. Acute pain (mainly the pain ratings) appeared to be a significant predictor for PCS, PASS, and PVAQ 1 week after surgery (deltaR(2) = [8.7% to 11.3%]). In contrast, the attentional biases in the dot-probe task could not be predicted by the pain ratings. The levels of pain catastrophizing and pain hypervigilance increased in the acute phase after surgery when influenced by acute pain and declined, along with pain anxiety, during the next 3 months. In conclusion, a one-time intense pain experience, such as acute postoperative pain, appeared to produce at least short-lived changes in the attentional and emotional processing of pain.

Pain catastrophizing changes during the menstrual cycle

Pain catastrophizing is an important predictor of pain intensity and pain-related outcomes. Many studies have shown that the level of this phenomenon is higher in women compared to men. The aim of this study was to investigate whether there is a difference in pain catastrophizing in women during the different phases of their menstrual cycle and whether there is a difference in pain catastrophizing depending on the history of childbirth and dysmenorrhea. A prospective study was conducted among 149 healthy women aged 18-35, with a regular menstrual cycle, 80 of which were nulliparous. The participants filled a sociodemographic questionnaire at the enrollment and the Pain Catastrophizing Scale on the 1st, 12th, and 20th day of the menstrual cycle. Pain catastrophizing scores, including all the subscales, significantly varied throughout the menstrual cycle, being highest on the first day of menstrual cycle and declining subsequently. Pain catastrophizing scores were higher in nulliparous than in parous women. Higher pain catastrophizing scores on the first day of the menstrual cycle were found in dysmehorrhoic women and women who regularly use analgesics for dysmenorrhea. Knowing that pain catastrophizing varies throughout the menstrual cycle may help in creating interventions for pain prevention and treatment in cycling women.

A rise in pain threshold during labor: A prospective clinical trial

To evaluate changes in pain threshold before, during and after labor in a prospective clinical trial. Forty pregnant women at term were included. Pain threshold in 18 specific pressure points was evaluated using a dolorimeter. Woman underwent pain threshold assessment at term before labor, during the active phase of labor and postpartum. Subjective pain intensity was assessed by the parturient using the Verbal Rating Scale (VRS). Pain threshold was significantly higher during active phase of labor. There was a significant decline in pain threshold after labor as compared to pain threshold during labor (2.507+/-0.947 and 2.608+/-1.023, respectively, p=0.01). Pain intensity using the VRS score was higher during labor than before labor (4.8+/-2.7 and 2.4+/-2.6 p<0.001). We found a significant rise in pain threshold during labor in term pregnancies. This rise may have an intended protective effect during the intense labor pain experience.

Studying sex and gender differences in pain and analgesia: a consensus report

In September 2006, members of the Sex, Gender and Pain Special Interest Group of the International Association for the Study of Pain met to discuss the following: (1) what is known about sex and gender differences in pain and analgesia; (2) what are the "best practice" guidelines for pain research with respect to sex and gender; and (3) what are the crucial questions to address in the near future? The resulting consensus presented herein includes input from basic science, clinical and psychosocial pain researchers, as well as from recognized experts in sexual differentiation and reproductive endocrinology. We intend this document to serve as a utilitarian and thought-provoking guide for future research on sex and gender differences in pain and analgesia, both for those currently working in this field as well as those still wondering, "Do I really need to study females?"

Quantification of the pain terms hurt, ache and pain among nursing students

The aim of this study was to determine the quantitative meaning nursing students ascribe to the pain terms hurt (ont), ache (värk) and pain (smärta). In total, 549 nursing students filled in a questionnaire including questions about age, gender, and health care work experience. The students were also requested to rate response using a Visual Analogue Scale (VAS) rating for different statements about hurt, ache and pain. The results show that there were significant differences (p < 0.001) between rated intensity of the statements of hurt, ache and pain. There were, however, large variations in the students' ratings of the pain terms; hurt ranged from 3 to 97 mm, ache from 7 to 97 mm and pain from 27 to 100 mm. There were no significant differences between male and female students regarding their ratings of hurt and ache when they were used to describe the worst self-experienced pain. Female students rated their experience of pain significantly higher (p < 0.001) on the VAS compared with male students. There was no significant correlation between previous experience of health care work and rated intensity of hurt, ache and pain. In conclusion, this study shows that there exist significant differences between the pain terms hurt, ache and pain according to a rating on a VAS. However, the results also demonstrate that there are large individual variations in how the students quantify the fictitious patient statements of hurt, ache and pain.

Pressure pain threshold changes after repeated mechano-nociceptive stimulation of the trapezius muscle: possible influence of previous pain experience

We examined the relation between repeated noxious pressure over the trapezius muscle and changes in pressure pain thresholds (PPTs) in a before-after trial design. A conditioning series of 30 mechano-nociceptive stimuli was applied manually with a handheld algometer probe, and PPTs were measured over 1 trapezius muscle (skin anaesthetized) in 27 healthy women before and after the intervention. With a mean stimulation rate of 0.40 Hz and a mean nociceptive stimulation intensity of 1.78 x Threshold, subjects were found to systematically react with a change in PPT, either a decrease or an increase. Normalized data, transformed into mean unidirectional PPT differences, showed statistically highly significant changes after intervention. The relative risk of reacting with lowered PPTs on noxious stimulation was 3.7 times higher for subjects who had not given birth to children than for subjects who had given birth to 1 or several children (P<.046). When 11 subjects were tested at a second session, a clear correlation of PPT reactions (r=0.527; P<.001) was found. In summary, repetitive mechano-nociceptive stimulation of the trapezius muscle in healthy females evokes moderate and temporary changes in PPT that last for at least 35 minutes after cessation of stimulation.

PERSPECTIVE

A possible development of the response with transiently decreased PPTs into a model for human muscle pain is an intriguing possibility, since other models usually involve the introduction of chemical or thermal agents in the muscle, but this must await further research.

Experimental Heat Pain for Detecting Pregnancy-Induced Analgesia in Humans

Animal studies suggest that increased circulating estrogen and progesterone, and activation of the endorphin system cause prenancy-induced antinociceptive effects. Human studies have provided inconsistent results and have often lacked a nonpregnant control group. In this study, we compared sensitivity to experimental heat and cold pain in pregnant and nonpregnant women. Nineteen healthy nonpregnant female volunteers and 20 pregnant women at term were enrolled. Pain threshold and tolerance were examined using experimental heat-induced pain and cold pressor pain models. Subjects were evaluated pre- and 1-2 days post-delivery (pregnant), or on consecutive days (nonpregnant). Heat pain tolerance was significantly increased in the pregnant women during pre and postdelivery when compared with nonpregnant controls (50.0 +/- 1.0 vs 49.0 +/- 1.2 and 50.1 +/- 0.7 vs 49.2 +/- 1.2 degrees C; mean +/- sd). However, pain induced by the cold pressor test was endured for a similar amount of time by both study groups. Pregnancy-induced analgesic effects at term can be detected in a model of experimental heat pain. These effects persist during the first 24-48 h after delivery. Experimental heat pain is a suitable modality for further characterizing the phenomenon of pregnancy-induced analgesia in humans.

What determines the analgesic effect of paracervical block?

BACKGROUND

The objective of the study was to evaluate the analgesic effect of paracervical block (PCB) in labor pain relief and to discover the determinants associated with good analgesia.

METHODS

In a prospective trial, 341 women received PCB for pain relief in the first stage of labor, with 10 ml of 0.25% levobupivacaine or racemic bupivacaine. All these pregnancies were uncomplicated and the progress of labor was normal. The analgesic effect of PCB was measured by using a visual analog scale (VAS). The factors associated with good pain relief (>50% decrease in the VAS score within 30 min) were analyzed statistically by Student's t-test or the Mann-Whitney test (continuous variables), Fisher's exact test (categorial variables) and after univariate analysis by logistic regression analysis. For pairwise comparisons, Wilcoxon's signed ranks test was used.

RESULTS

Good pain relief was achieved in 47.2% of the cases. 12.3% of the parturients needed subsequent epidural or spinal analgesia. In logistic regression analysis, primiparity, a high pain score before PCB, and PCB given by a specialized obstetrician were found to affect the level of pain relief 30 min after PCB.

CONCLUSIONS

The best pain relief after PCB was achieved among primiparas. Good pain relief was connected with a high pain score before PCB and an experienced obstetrician.

Delivery room analgesia: an analysis of maternal satisfaction

On the first post-partum day, 324 mothers completed a questionnaire designed to assess maternal perception of delivery room experience. Antenatal pain expectation, actual pain severity, analgesia received, as well as maternal satisfaction and choice of analgesia for future deliveries were recorded. Forty-five percent of primiparae and 36% of multiparae reported that they anticipated suffering extreme pain during delivery. The incidence of unbearable pain was similar among patients who received no analgesia or intravenous pethidine but significantly (P<0.0001) higher when compared to epidural analgesia. During the first stage of labour, continuous epidural analgesia was associated with severe or unbearable pain in 51% and 58% of primiparae and multiparae, respectively. The incidence of severe or unbearable pain during the second stage of labour was 43% and 46% for primiparae and multiparae, respectively. Patient satisfaction with epidural analgesia did not correlate with subjective pain scores. Among mothers who received continuous epidural analgesia 70% described their experience as good or excellent and 65.8% indicated that they would request similar pain relief in the future. Despite advances in obstetric analgesia, women anticipate and actually experience severe pain during childbirth. However, due to psychological and cultural factors, as well as possible post-partum euphoria, satisfaction with the delivery room experience is high.

Douleur et analgésie obstétricales

GOAL AND METHODS

Labor pain is of major concern since most parturients experience significant pain of extremely severe intensity for many. The purpose of this review was to provide an overview of the mechanisms and pathways of labor pain (including new insights on integration of the nociceptive signal) and to emphasize the need of effective labor pain relief.

RESULTS

Labor pain can have deleterious effects on the mother, on the fetus and on labor outcome itself. Among the current methods of obstetric analgesia, regional analgesia (the most widespread technique being epidural analgesia) offers the best effectiveness/safety ratio thanks to pharmacological innovations. Systemic analgesia (parenteral opioids, nonopioid painkillers and inhaled anesthetic agents) provides an alternative to regional analgesia but remains less effective and more hazardous. Non-drug approaches (namely psychoprophylaxis and physical methods) may be effective when used with epidural analgesia but are often not potent enough when used alone.

CONCLUSION

Despite its complex pathophysiology, labor pain can be efficiently managed. Thanks to multidisciplinary care, obstetric analgesia (mainly epidural analgesia) prevents deleterious effects of labor pain on the mother and fetus.

Vascular maternal reactivity and neonatal size in normal pregnancy

OBJECTIVE

The purpose of the present study was to determine the associations of cold pressor test (CPT) cardiovascular reactivity with gestational age at birth and neonatal size in normotensive pregnant women.

METHODS

Seventy (70) healthy pregnant women were enrolled. The CPT consisted of introducing the patients' hands in cold water (4 degrees C) for 3 min. An automatic oscillometric device was used to record blood pressure (BP) every minute for the following 5 min. Perinatal results were correlated with CPT findings.

RESULTS

Vascular reactivity assessed by CPT was higher in pregnant hypertensive women and in women with a hypertensive family history. Mean BP increases caused by CPT showed a significant negative correlation for gestational age (r = -0.58, p < 0.001) and cephalic perimeter (r = -0.57, p = 0.03). Diastolic BP increases caused by CPT were negatively correlated with newborn weight (r = -0.78, p < 0.001). Predictable newborn weight, gestational age, and cephalic perimeter were 4046 (47 x diastolic BP increase), 40.2 (0.07 x mean BP increase), and 35.8 (0.09 x mean BP increase), respectively.

CONCLUSIONS

Results show that every mm Hg diastolic BP increase in response to CPT was correlated with a 47-g decrease in the newborn normal weight. Furthermore, every mean mm Hg BP increase in response to CPT was associated with a 0.07-week decrease in the newborn normal gestational age and a 0.09-cm decrease in the normal cephalic perimeter at birth.

Reduced pain tolerance during and after pregnancy in women suffering from fear of labor

Pain tolerance in women suffering and not suffering from fear of labor during and after pregnancy were compared. Twenty women with labor fear and 20 control women were subjected to a cold pressor test (CPT) on average 1 month before delivery and 9 months later. Half the volunteers were nulliparous and half parous. Pain endurance time (PET) and intensity of pain (Visual Analogue Scale, VAS) during CPT was assessed. Patients in the fear group tolerated CPT for a significantly shorter time than did women without fear both in pregnancy (154.8+/-109.9 s vs. 282.5+/-60.1 s (mean+/-SD), P<0.001), and in the postpartum period (128.6+/-111.7 s vs. 279.6 +/-60.3 s, P=0.002). Those with labor fear experienced CPT as significantly more painful than did the controls both during pregnancy (VAS 6.68+/-1.9 vs. 3.78+/-2.0 (mean+/-SD), P<0.001) and after (VAS 7.73+/-1.5 vs. 5.92+/-3.0, P=0.04). PET and VAS values correlated during pregnancy (r=-0.62, P<0.001), but not after pregnancy (r=-0.30, not significant). Parity was not associated with either PET or VAS scores. As a rule, pain in all women during CPT was regarded to be lower during pregnancy than after pregnancy (VAS 4.87+/-2.4 vs. 6.60+/-2.6, P=0.001). Patients with fear of labor were characterized by pain intolerance also in circumstances other than labor. This fact may indicate enhanced sensitivity to pain-causing mechanisms in women who develop fear of labor.

Subjective pain experience of people with chronic back pain

BACKGROUND AND PURPOSE

Studies into the effect of pain experience on those who have it have largely focused on the views and interpretations of researchers gained by the use of assessment tools aimed at measuring pain. The purpose of this study was to explore and describe pain, as experienced by those with chronic back pain, and to document 'insider' accounts of how pain is perceived and understood by those who have it.

METHOD

Unstructured interviews using the framework approach. Subjects were sampled for age, sex, ethnicity and occupation, from new referrals with back pain to a rheumatology outpatient clinic. Eleven subjects (5 M; 6 F) agreed to be interviewed. Interviews were unstructured, but followed a topic guide. Subjects were interviewed in English (nine) or their preferred language (two). Tape-recordings of interviews were transcribed verbatim and read in depth twice to identify the topics or concepts. Data were extracted in the form of words and phrases by use of thematic content analysis. The themes were pain description and amount of pain. An independent researcher reviewed the data and confirmed or contended the analysis.

RESULTS

All subjects, except one, provided descriptors of the quality of their pain. The use of simile was common to emphasize both what the pain was, and what it was not. Five subjects expressed a loss of words in trying to describe their pain. Only 13 of 29 different pain descriptors used were commensurate with those in the McGill Pain Questionnaire (Melzack, 1983). Subjects had great difficulty quantifying their pain intensity. Several explained how the pain fluctuated, thus, quantifying pain at one point in time was problematic. Only one subject offered a numerical description of pain intensity.

CONCLUSIONS

Subjects provided graphic and in-depth descriptions of their pain experience, but these bore little resemblance to commonly used assessment tools. The findings challenge the appropriateness of such formal instruments.

Psychosocial factors influencing personal control in pain relief

A questionnaire was administered to 100 women (50 primigravidae, 50 multigravidae) to investigate the influence of psychosocial factors on personal control in pain relief. Personal control was measured using a 36-item scale based on the concept of 'Rule'. The women were asked to rate each rule on a 7-point Likert scale. Measures of psychosocial factors included assessment of the women's expectations of labour pain, maternal confidence, pain intensity, antenatal training and partner support. Demographic variables including parity were also recorded. The questionnaires were completed prior to and within 48 h following the women's delivery (whilst they were inpatients on the postnatal ward).Two variables, antenatal training and pain intensity, emerged as predictors of personal control in pain relief following stepwise multiple regression analysis. These findings have implications for clinical practice particularly in the area of antenatal care and planning care during labour.

The Childbirth Self-Efficacy Inventory: a replication study

In 1993 Lowe developed the Childbirth Self-Efficacy Inventory (CBSEI). This is a self-administered, 62-item, Likert tool which measures women's confidence in their ability to cope with labour. The tool is valid and reliable for use in American culture but had not been tested in Northern Ireland, therefore a replication study was deemed necessary. The research study set out to replicate Lowe's study and to test the potential application of this tool in clinical midwifery practice. A convenience sample comprising a cohort of 126 women attending an urban maternity unit in Northern Ireland formed the study population and a response rate of 64% was achieved. The tool was administered antenatally, intranatally and postnatally. The predictive validity of the instrument was tested to determine actual coping behaviours in labour (Pearson's r=0.3963, P < 0.00 for active labour; r=0.5149, P < 0.00 for second stage labour). This work confirms the CBSEI as a measurement of confidence in women's ability to cope in labour. The authors recommend the utility of the CBSEI in midwifery practice as a tool for the identification of women who will require extra support in labour and pregnancy.

Are women requiring unplanned intrapartum epidural analgesia different in a low-risk population?

We studied 645 full-term low-risk women in early labour in 6 units to evaluate the effects of maternal characteristics and obstetric management in early labour on the use of epidural analgesia, and to analyse the relationship between epidural analgesia, progress of labour and mode of delivery using multiple logistic regression. Among variables present in early labour, nulliparity, ethnicity and obstetric unit were the strongest predictors of epidural analgesia requirement. In nulliparous women, obstetric unit affected use of epidural analgesia (P<0.05) and induction of labour was associated with increased use of epidural analgesia (odds ratio 3.45, 95% CI: 1.45-7.90). In multiparous women, only ethnicity was statistically significant (P<0.05). Epidural analgesia was associated with longer labours and more instrumental deliveries (odds ratio 2.93, 95%CI: 1.48-5.83). In the epidural group, however, we found a positive correlation between first stage duration and elapsed time before epidural analgesia. Furthermore, rate of cervical dilation was similar in the non epidural group throughout the first stage (mean 3.41 cm/h, 95%CI: 3.19-3.63) and in the epidural group after epidural analgesia decision (mean 3.99, 95% CI: 2.96-5.02), while the mean cervical dilatation rate before epidural analgesia was 0.88 cm/h (95% CI: 0.72-1.04). The need for epidural analgesia is, therefore, multifactorial and difficult to predict. Whereas nulliparity increases epidural analgesia requirement, data on the progress of labour before pain relief suggest that epidural analgesia is a marker of pain severity and/or labour failure rather than the cause of delayed progress in low-risk pregnancies.

Adolescents' perceptions of pain during labor

This descriptive study systematically described the quality and intensity of adolescents' pain during the progression of labor. The Gaston-Johansson Pain-o-Meter was administered to 33 adolescents during the three labor phases (2-4 cm, 5-7 cm, and 8-10 cm) following a contraction. The most frequently selected sensory words were cramping in Phase I and pressing in Phases II and III. Miserable and killing were the most commonly chosen affective words during the three labor phases. Using the Gaston-Johansson Pain-O-Meter and the Gaston-Johansson Pain-O-Meter Visual Analogue Scale, the total pain intensity scores were highest during phase III of labor and delivery. At-test of independent samples found that quality and intensity pain scores for primiparous and multiparous adolescent participants were not significantly different during the progression of labor. The findings of the study illustrate the value of using objective measures, such as the Gaston-Johansson Pain-O-Meter and the Gaston-Johansson Pain-O-Meter Visual Analogue Scale, to assess pain during labor. The study also demonstrated that nurses can use these tools with minimal training.

Maternal expectations and experiences of labour pain and analgesia: a multicentre study of nulliparous women

Six hospitals with large maternity units in five different European countries were involved in this multicentre study. At least 100 primiparae for each country were examined. All mothers received two standardized interviews, one during the last month of pregnancy, and one 24 h after delivery. Maternal expectations and experiences of pain, pain relief, and satisfaction with analgesia and childbirth were assessed by a 100 mm visual analogue scale (VAS). Almost all mothers were seen regularly by an obstetrician or a midwife during pregnancy, had prepared childbirth classes and received antenatal information on labor analgesia techniques. Differences between the five groups were noted in the level of education and socio-economic status. Maternal expectations of labor pain and the answers to the pre-delivery interview varied significantly between the centers, as did maternal knowledge, expectation and ultimate choice of analgesic technique. Generally speaking the level of maternal satisfaction with analgesia and childbirth experience was high; however, epidural analgesia was more effective than other methods of pain relief (P<0.0001). The most satisfied mothers were those who expected more pain, were satisfied with the analgesia received and had good pain relief after analgesia (P<0.001).

Ethnicity and use of obstetrical analgesia: do Pakistani women receive inadequate pain relief in labour?

OBJECTIVE

To study whether the use of analgesic treatment in labour is influenced by ethnicity.

DESIGN

A cross-sectional study of hospital patients. Setting; the two municipal hospitals, Ullevål and Aker, in Oslo, Norway. Subjects; a total of 137 obstetrical patients, 67 Pakistani women and 70 Norwegian women. Main outcome measure; use of analgesics in labour.

RESULTS

30% of the Pakistani and 9% of the Norwegian women received no analgesia in labour. Pethidine injection was the preferred analgesic administered to Pakistani women. Women of Pakistani origin received epidural infusion or nitrous oxide and oxygen gas less frequently than Norwegian women. They also received fewer combinations of other analgesic methods. When adjusted for the mothers' age, parity and duration of delivery, Pakistani origin was the only significant predictor for receiving no analgesia in labour.

CONCLUSION

Women of Pakistani origin were more than three times as likely not to receive analgesia in labour as Norwegian women. The health services offered to Pakistani women in labour were different from those offered to Norwegian women. These results indicate that women of Pakistani origin may be offered insufficient obstetrical analgesia, or that Norwegian women received unnecessary pain relief in labour.

The intensity of labor pain in grand multiparas

BACKGROUND

The purpose of the current study was to investigate differences in pain experiences and requirements for pain control in parturients with different birth experience. Previous studies have shown that the labor pain experience is significantly less intense in multiparas than in primiparas and requirements for analgesic treatment have therefore been assumed to be minimal in this group.

METHODS

The pain experience during labor was assessed by 70 consecutive grand multiparas (a minimum of five previous deliveries) compared to that of primiparous (n=70) and II-V parous women (n=70). Pain intensity was repeatedly assessed on a pain intensity scale (0-10) according to the progress of cervical dilatation at the first and second stage of labor.

RESULTS

During the latent phase of cervical dilatation (0-3 cm) grand multiparas had a median pain score of 3 compared to 4 in II-V paras and 6 in primiparas (p<0.001). At the end of the first stage and during the second stage the intensity of pain in grand multiparas was significantly higher compared to that in primiparas (median scores 7 to 8 vs 6 to 7, p<0.05). Epidural blocks were administered to 40% of primiparas, 3% of II-V paras and to no grand multiparas (p<0.0001). Twenty-one percent of grand multiparas rated their pain as intolerable (pain scores 9-10) during the second stage compared to 10% of primiparas (p<0.05%). On the third day after delivery, 47% of grand multiparas regarded their analgesia insufficient.

CONCLUSIONS

The majority of parturients, including grand multiparas, suffered from intense pain during labor. After delivery, a significant number of grand multiparas felt that they had received insufficient pain relief.

Maternal expectations and experiences of labour pain--options of 1091 Finnish parturients

A prospective survey of 1091 Finnish parturients was conducted in order to ascertain mothers' expectations for labour pain relief, to measure the actual pain during all three stages of labour and to question their satisfaction and the adequacy of pain relief on the third day following delivery. Antenatal expectations for pain relief were surveyed. Mothers were questioned on pain levels in the delivery room and 3 days after giving birth. Pain levels were ascertained using a visual pain score method. Antenatally, 90% of all parturients anticipated a need for pain relief during labour. In the delivery room over 80% of all parturients described their pain as very severe to intolerable, only 4% of the multiparous had low pain scores (0-2). After pain treatment 50% of multiparous women still had pain scores from 8 to 10, which reflects a lack of effective pain relief. Dissatisfaction with the childbirth experience was very low, and was associated with instrumental deliveries, but not with the usage of analgesia. 51% of all parturients complained of inadequate pain relief during childbirth, which, in multiparous women, was significantly associated with the second stage of labour.

Facial sensory evoked muscle potentials during labour. A continuous objective monitor of adequacy of analgesia?

We prospectively studied the relationship between upper facial sensory-evoked muscle potential amplitude, uterine contraction amplitude and heart rate in 20 healthy parturients during the first stage of labour. Monitoring began when minimal pain was reported and continued until severe pain occurred and extradural analgesia was established. Pain intensity was assessed by each patient using a 10 cm visual analogue score. Heart rate was recorded using a pulse oximeter. Sensory evoked muscle potential was derived from frontalis biopotentials that were rectified, integrated and digitised by an Anaesthesia and Brain activity Monitor (Datex, Helsinki, Finland). An additional signal filter was included in the pre-amplifier to improve the signal-to-noise ratio. The rms amplitude of successive 10s samples of sensory evoked muscle potential, as well as heart rate and the output from an external tocotransducer, were then graphically displayed to allow assessment of temporal relationships. The data were assessed using correlation analysis and hypergeometric probability distribution. Before extradural analgesia (mean pain score 7.5 cm, SD 1.5 cm) a significant relationship was demonstrated between sensory evoked muscle potential and uterine contraction, p < 0.001). No constant relationship was seen between heart rate and uterine contraction. Following extradural analgesia (mean pain scores of 2.1 cm, SD 1.3 cm) a variable relationship between sensory evoked muscle potential and uterine contraction amplitude, and heart rate and uterine contraction, was recorded. A continuous display of the relationship between filtered sensory evoked muscle potentials of the frontalis muscle and uterine contraction may, in the future, permit an objective assessment of the adequacy of analgesia following extradural analgesia for the pain of labour.