Women In Active Labor Research Articles

Cervical Stroma Apoptosis in Pregnancy

In Brief Objective To determine whether the percentage of apoptotic nuclei is different in cervical stroma of pregnant laboring women compared with nonpregnant women and pregnant nonlaboring women. Methods We took cervical stromal biopsies during cesarean delivery at the level of the lower uterine segment from ten women in active labor and 13 women before labor. In addition, we took biopsies of cervical stroma at the level of the internal cervical os from hysterectomy specimens in ten reproductive-aged women. Cryosections were then analyzed using terminal deoxynucleotidyl transferase–mediated deoxyuridine triphosphate nick-end labeling staining. Tissue specimens were analyzed with ligation-mediated polymerase chain reaction to visualize nucleosomal ladders characteristic of apoptosis. To detect a 10% difference in the percentage of apoptotic cells per subject between study groups assuming a power of 0.90, an alpha of .05 in approximately ten subjects per group was needed. Results The median percentage of apoptotic nuclei was 0.7 (interquartile range 0.4, 1.4) for the nonpregnant group, 7.5 (interquartile range 6.6, 11.2) for the pregnant nonlaboring group, and 11.6 (interquartile range 8.3, 16.7) for the pregnant laboring group (P < .001). The percentage of apoptotic nuclei differed significantly across the three study groups. Using ligation-mediated polymerase chain reaction, nucleosomal ladders were seen in the specimens from pregnant women but not in the specimens from nonpregnant women, confirming the increase in stromal apoptosis seen with pregnancy. Conclusion Apoptosis of cervical stromal cells may play a role in the remodeling of the cervix during pregnancy and contribute to cervical changes during labor. Cervical stroma cell apoptosis is increased in pregnancy and in labor compared with nonpregnant women.

Cervical stroma apoptosis in pregnancy

Objective: To determine whether the percentage of apoptotic nuclei is different in cervical stroma of pregnant laboring women compared with nonpregnant women and pregnant nonlaboring women. Methods: We took cervical stromal biopsies during cesarean delivery at the level of the lower uterine segment from ten women in active labor and 13 women before labor. In addition, we took biopsies of cervical stroma at the level of the internal cervical os from hysterectomy specimens in ten reproductive-aged women. Cryosections were then analyzed using terminal deoxynucleotidyl transferase–mediated deoxyuridine triphosphate nick-end labeling staining. Tissue specimens were analyzed with ligation-mediated polymerase chain reaction to visualize nucleosomal ladders characteristic of apoptosis. To detect a 10% difference in the percentage of apoptotic cells per subject between study groups assuming a power of 0.90, an alpha of .05 in approximately ten subjects per group was needed. Results: The median percentage of apoptotic nuclei was 0.7 (interquartile range 0.4, 1.4) for the nonpregnant group, 7.5 (interquartile range 6.6, 11.2) for the pregnant nonlaboring group, and 11.6 (interquartile range 8.3, 16.7) for the pregnant laboring group ( P < .001). The percentage of apoptotic nuclei differed significantly across the three study groups. Using ligation-mediated polymerase chain reaction, nucleosomal ladders were seen in the specimens from pregnant women but not in the specimens from nonpregnant women, confirming the increase in stromal apoptosis seen with pregnancy. Conclusion: Apoptosis of cervical stromal cells may play a role in the remodeling of the cervix during pregnancy and contribute to cervical changes during labor.

Calcium homeostatic pathways change with gestation in human myometrium.

A rise in intracellular calcium is the primary trigger for contractile activity in pregnant human myometrium. It is hypothesized that key proteins involved in myometrial calcium homeostasis are gestationally regulated and play an important role in the preparation for labor. The aims of the study were to investigate the role of sarcoplasmic reticulum Ca ATPases (SERCAs) in regulating spontaneous contractile activity in myometrium, and to determine the expression of SERCA isoforms 2a and 2b, and the plasma membrane Ca ATPase (PMCA), at term and during labor. Western blot analysis demonstrated that the expression of SERCA 2a and 2b significantly increased in myometrium of women in labor compared with those not in labor. The augmentation of contractile activity in laboring myometrium in the presence of a SERCA 2 inhibitor, cyclopiazonic acid (CPA), demonstrated the functional significance of this observation. It is interesting that the application of CPA in the presence of a calcium-activated potassium channel inhibitor to term nonlabor myometrium mimicked the response of myometrium from women in active labor to CPA alone. We conclude that the activity of SERCA isoforms becomes increasingly important in the maintenance of regular contractile activity during labor and may compensate for the functional loss of other calcium control pathways at term.

“Walking” Epidural Anesthesia: Are Test Doses Necessary? Cohen et al. (page 387)

Although the actual benefits of walking during labor are unproven, many women express the desire to walk during labor. Combined spinal–epidural analgesia performed with intrathecal opioids has gained acceptance in this application because it causes minimal motor block. Cohen et al. designed a randomized, double-blind study to evaluate analgesic effectiveness and ability to walk after receiving a bolus of either 0.0625% bupivacaine or 0.125% bupivacaine (with sufentanil), with or without previous administration of the traditional lidocaine–epinephrine test dose.Sixty healthy women in active labor, all of whom requested epidural analgesia and who expressed a desire to walk during labor, participated in the study. Visual analog pain scores were 3 or more, and cervical dilation was between 1 and 6 cm for participants. All subjects received a 3-ml epidural injection (a 1.5% lidocaine–epinephrine test dose or bupivacaine) and 3 min later, 12 ml bupivacaine with 10 μg sufentanil injected in two increments 3 min apart. Maternal blood pressure and visual analog pain scores were recorded before study drug administration and after completion of the bolus injections at 5, 10, 15, 20, 30, and 60 min, and then hourly for 4 h until delivery. Data relating to ambulation, balance, proprioception, and motor block were collected at baseline, 30 min, 1 h, and then hourly until delivery. Ability to walk with little or minimal assistance across the room was rated as either “yes” or “no.” Women who walked spent approximately 5–10 min out of bed and usually attempted to void, and then were reassessed for balance, among others.A high percentage of women in all groups (75–93%) walked at some stage during labor. The group receiving the bolus of 0.125% bupivacaine with sufentanil, without a previous test dose, experienced the best analgesia and walked earlier than women in all other groups. Fewer women walked within 1 h of block placement when they received a test dose before 0.125% bupivacaine. With or without a test dose, 0.0625% bupivacaine with sufentanil provided inadequate analgesia. Women in the two latter groups required additional bupivacaine, which in turn impaired their ability to walk. The authors suggest that, based on these results, walking during the early postblock period would be possible by omitting the lidocaine–epinephrine test dose and using 0.125% bupivacaine for the initial bolus.

Is the attenuation of β-adrenergic agonist efficacy during labor caused by elevated prostaglandin E levels?

Objective: Our purpose was to investigate whether attenuation of β-adrenergic agonist efficacy during labor is due to elevated prostaglandin E levels. Study Design: β-Receptor function (response to β-agonist or forskolin) was tested in mononuclear leukocytes collected from women at term before or during labor. β-Receptor function was also tested in mononuclear leukocytes of nonlaboring patients after in vitro incubation with oxytocin (1 μmol/L), prostaglandin E 2 (10 μmol/L), prostaglandin F 2 α (10 μmol/L), or buffer alone. Results: Mononuclear leukocytes from women in active labor exhibited a significant attenuation of β-adrenergic receptor function as a result of reduced adenylyl cyclase activity. This effect could be induced in mononuclear leukocytes from nonlaboring women by preincubation with prostaglandin E but not oxytocin or prostaglandin F. Conclusions: Prostaglandin E induces heterologous desensitization of the β-adrenergic receptor system in mononuclear leukocytes, comparable to that seen during labor. We speculate that during labor the elevated levels of prostaglandin E may induce similar effects on the myometrium, thereby decreasing the efficacy of β-agonists as tocolytics. (Am J Obstet Gynecol 1998;179:1168-74.)

Labour analgesia with intrathecal fentanyl decreases maternal stress

Lumbar epidural analgesia (LEA) decreases maternal stress as measured by maternal circulating plasma catecholamine concentrations. Intrathecal fentanyl (ITF) provides effective labour analgesia but its effect on maternal epinephrine (Epi) and norepinephrine (NE) concentrations is not known. This study assesses whether ITF reduces maternal stress in the same manner as conventional LEA. Twenty-four healthy women in active labour received either 25 micrograms ITF (n = 12) or epidural lidocaine 1.5% (n = 12) for analgesia. Venous blood samples were collected before anaesthesia and at five minute intervals for 30 min following anaesthesia for the measurement of plasma Epi and NE by high performance liquid chromatography. Maternal blood pressure (BP), heart rate (HR), visual analog scores (VAS) to pain and pruritus were recorded at the same time. Both ITF and LEA decreased pain VAS scores, maternal BP, and plasma Epi concentrations with only minimal effects on plasma NE concentrations. Intrathecal fentanyl (ITF) and LEA reduced plasma epi to a similar extent, with ITF reducing the levels slightly faster than LEA. Intrathecal fentanyl(ITF) and LEA reduced plasma Epi concentrations by 52% and 51%, respectively (P value < 0.01). We conclude that ITF is as effective as LEA in producing pain relief in the labouring patient. Intrathecal Fentanyl (ITF) is also capable of reducing maternal plasma epinephrine concentration, thus avoiding the possibly deleterious side effects of excess amounts of this catecholamine during labour.

Intrathecal Sufentanil for Labor Analgesia

Sensory changes and hypotension occur after intrathecal sufentanil (ITS) is given during labor.The goal of this study was to determine whether sensory changes are predictive of hemodynamic changes or duration of pain relief. We also examined whether sensory and hemodynamic changes relate to the concentration of ITS administered. Forty-five ASA physical status I and II women in active labor were randomly assigned to receive 10 micro g ITS diluted in either 1, 2, or 3 mL of normal saline (15 in each group). An observer blinded to treatment recorded verbal pain scores, blood pressure, and sensory changes to light touch, pinprick, and cold at frequent intervals. Excellent analgesia was obtained in 42 of 45 patients. There were no differences among the groups with respect to the number of patients with sensory changes, the duration of analgesia or sensory changes, the quality of analgesia, or the severity of hypotension. The groups were therefore combined for further analyses. Among this combined group, the duration of analgesia was 99 +/- 7 min (mean +/- SE). Cold, pinprick, and light touch sensation were decreased in 66%, 50%, and 33% of patients, respectively. Motor block was absent in all patients. The duration and quality of analgesia were similar in subjects with and without sensory changes. Systolic blood pressure decreased 23 +/- 2 mm Hg (P < 0.05) during the first 30 min after ITS, and six patients were given ephedrine. The magnitude of blood pressure change was not affected by the diluent volume or the presence of sensory changes. Because sensory changes were not predictive of the duration or quality of analgesia or the degree of hemodynamic change, we conclude that analgesia with ITS is predominantly mediated via spinal cord opioid receptors rather than by a local anesthetic-type conduction blockade. (Anesth Analg 1997;84:346-51)

The efficacy of intrathecal injection of sufentanil using a microspinal catheter for labor analgesia.

Intrathecal sufentanil can provide labor analgesia. We investigated the efficacy of multiple injections and the maternal and neonatal effects of intrathecal sufentanil during labor. Seventeen healthy women in active labor received multiple injections of intrathecal sufentanil of 5 micrograms each through microspinal catheters. Overall maternal satisfaction of analgesia was quantified using 10 cm visual analogue scales and side effects were evaluated. Neonatal outcome was also determined. Onset of analgesia was less than 5 min after the first injection and lasted approximately 148 min. Tolerance developed for the successive injections. The mean onset times were 12.9 and 20.1 min and the durations were 76.6 and 33.9 min for the second and third injections, respectively (P < 0.05). Failure to obtain analgesia developed in all patients after the forth injection. No motor blockade was observed in any of the patients. Mild or moderate pruritus developed in 88% of the patients. Mean systolic blood pressure decreased by a maximum of 11.3% at 30 min and up to 90 min (P < 0.05) after the first injection; three patients required ephedrine treatment. No significant hemodynamic changes were observed after subsequent injections. Five patients experienced transient decrease in sensation. Neonatal status, as evaluated by Apgar scores, Neurological Adaptive Capacity Scores (NACS), fetal heart rate (FHR), and umbilical cord acid-base status, were within normal limits. Results from our study suggest that multiple small doses of sufentanil administered intrathecally provided satisfactory analgesia for parturients with short duration of labor since acute tolerance developed with multiple injections. High incidence of mild or moderate pruritus was observed during the study. Close attention should be given to hemodynamically unstable patients when this technique is applied.

Prolactin concentrations in preterm and term pregnancy and labour.

Maternal plasma and amniotic fluid (AF) were obtained for measurement of prolactin concentrations from: 1) 20 patients with preterm labor and intact membranes who delivered within one week of amniocentesis; 2) 20 patients with preterm labor who responded to tocolysis and delivered at term; 3) 20 women at term who were not in labor and 4) from 20 women in active labor at term. No significant differences were found between: 1) maternal plasma prolactin concentrations in women with preterm labor who delivered prematurely and those who delivered at term (155 ng/ml vs 176.5 ng/ml); 2) patients at term who were not in labor (188 ng/ml) and those who were in labor (155 ng/ml); 3) AF prolactin concentrations in the two preterm labor groups (1987.5 vs 1282.5 ng/ml) and 4) AF prolactin concentration in the two term groups (562 ng/ml vs 701 ng/ml). Prolactin concentrations were generally significantly higher preterm than at term. We concluded that no significant changes in maternal plasma and amniotic fluid prolactin levels were found in preterm and term parturition.

Acute Tocolysis for Fetal Distress

Summary: Forty-six women in active labour who developed fetal distress requiring abdominal delivery were randomized to receive 0.25 mg of terbutaline (subcutaneously) or magnesium sulphate as a 4-g bolus (intravenously) to decrease uterine activity. The terbutaline-treated group in contrast to the magnesium sulphate-treated group had reduced uterine activity as measured by Montevideo units (p <0.002). This decrease in uterine activity was noted more rapidly in all 23 patients who received terbutaline, 1.8 ±0.74 minutes compared to 7.5 ±2.1 minutes in the 16 of 23 patients (magnesium sulphate-treated women) in whom a decrease in uterine activity occurred (p <0.001). Umbilical cord arterial blood pH at delivery was less than 7.20 in only 2 of the 23 patients treated with terbutaline versus 7 of the 23 in the magnesium sulphate-treated group. We conclude that terbutaline is an effective and more rapid-acting tocolytic agent to arrest uterine activity prior to delivery for fetal distress.

Topographic differences in amniotic fluid concentrations of prostanoids in women in spontaneous labor at term

These studies were designated to determine if there are differences in prostanoid concentrations between amniotic fluid (AF) retrieved transvaginally from the membrane forebag (lower or forebag compartment) and fluid retrieved by transabdominal amniocentesis from the ‘upper compartment’ in women in labor. Fluid was retrieved from 53 women in active labor who underwent transabdominal and transvaginal amniocentesis. Fluid was assayed for prostaglandin E 2 (PGE 2) and prostaglandin F 2α (PGF 2α), 13,14-dihydro-15-keto-prostaglandin F 2α (PGFM), thromboxane B 2 (TXB 2), and 6-keto-prostaglandin F 1α (6-k-PGF 1α) using sensitive and specific radioimmunoassays. Concentrations of all prostanoids measured were significantly higher in fluid retrieved by transvaginal than transabdominal amniocentesis; the magnitude of the increase (measured as the ratio of concentrations in the lower/upper compartment) was higher for PGF 2α and TXB 2 than for the other prostanoids measured; for each prostanoid measured, there was a significant correlation between the concentration in the upper and lower compartment.

Fetal middle cerebral artery blood flow during normal active labour and in labour with variable decelerations.

To assess the distribution of fetal blood flow impedance of the umbilical and middle cerebral artery in active uncomplicated labour and in labour complicated by variable decelerations. Blood flow impedance of the umbilical and fetal middle cerebral arteries was assessed by means of pulsed Doppler ultrasonography and measured by the resistance index (RI) and the systolic/diastolic ratio. 35 women at 38-40 weeks gestation admitted to, or monitored in the intrapartum unit. One group of 25 women had a normal active labour, the second group of 10 women were in active labour with moderate variable decelerations. A control group of 25 women--healthy pregnant women at term but not in active labour. All three groups were comparable for maternal age and parity. Hospital department of obstetrics and gynaecology, Israel. A prospective descriptive study. There was a 40% reduction in middle cerebral artery blood flow impedance in the two groups of women in active labour compared with the control group. Umbilical blood flow did not differ significantly between the three groups. Fetal middle cerebral blood flow impedance in labour was not significantly different in uncomplicated labours and those complicated by fetal heart rate decelerations. During active labour, mechanisms that may be unrelated to low fetal blood oxygen content reduce fetal brain blood vessel impedance.

Tumor necrosis factor in preterm and term labor

Our objective was to determine if labor (term and preterm) and microbial invasion of the amniotic cavity were associated with changes in amniotic fluid concentrations of tumor necrosis factor. Amniotic fluid was retrieved by transabdominal amniocentesis from 269 women in the following groups: midtrimester (n = 38), preterm labor with intact membranes (n = 52), preterm premature rupture of membranes (n = 74), term in active labor (n = 84), and term not in labor (n = 21). Fluid was cultured for aerobic and anaerobic bacteria and for Mycoplasma species. Tumor necrosis factor was measured with a commercially available enzyme-linked immunosorbent assay validated for amniotic fluid (sensitivity 60 pg/ml). Amniotic fluid from pregnant women in the second and third trimesters who were not in labor did not contain tumor necrosis factor. Among women in preterm labor, 92.3% (12/13) of patients with a positive amniotic fluid culture had detectable tumor necrosis factor in the amniotic fluid (median 820 pg/ml, range less than 60 to 2340 pg/ml). In contrast, only 10.2% (4/39) of women with a negative amniotic fluid culture had detectable tumor necrosis factor. Histopathologic chorioamnionitis was found in all patients who had a positive amniotic fluid culture, and tumor necrosis factor was detectable in the amniotic fluid of all but one of these patients. Among women in active labor at term, 25% (21/84) had detectable tumor necrosis factor in the amniotic fluid. Tumor necrosis factor was detected more frequently in the amniotic fluid of patients with a positive amniotic fluid culture than in patients with a negative culture (46.6% [7/15] vs 20.2% [14/69], p = 0.047). Amniotic fluid concentrations of tumor necrosis factor were significantly higher in patients with preterm premature rupture of membranes, labor, and a positive amniotic fluid culture than in the other subgroups of patients with preterm premature rupture of membranes. Parturition in the setting of microbial invasion of the amniotic cavity is associated with activation of the cytokine network as demonstrated by the detection of tumor necrosis factor in human amniotic fluid.

Regional Perinatal Care in Crisis: A Case Study of an Urban Public Hospital

Regionalized perinatal care is intended to guarantee pregnant women and neonates access to appropriate care regardless of ability to pay. Its effectiveness depends on the willingness of hospitals to transfer high-risk patients according to established protocols and affiliations. This study examines maternal transfers (n = 896) to Cook County Hospital (CCH), a public facility and a designated perinatal center in Chicago. In 1987 and 1988, the majority (68%) of maternal transfers to CCH came from out-of-network hospitals, and 52% of these came directly from another perinatal center. The data indicate that 62% of the out-of-network transfers who delivered were medically high-risk. The study also documents the transfer of women in active labor, a violation of federal law. The term "perinatal dumping" is introduced to mean the transfer of high-risk pregnant women between hospitals for economic rather than medical reasons. Strategies for safeguarding the integrity of regionalized perinatal care are discussed.

Amniotic fluid concentration of 5-hydroxyeicosatetraenoic acid is increased in human parturition at term

5-hydroxyeicosatetraenoic acid (5-HETE) is an arachidonate lipoxygenase product capable of stimulating uterine contractility in a dose-dependent manner in vitro. The purpose of this study was to determine if spontaneous human labor at term is associated with changes in the concentration of this metabolite in amniotic fluid. Fluid was retrieved from 36 women not in labor and from 30 women in active labor at term. 5-HETE was determined by radioimmunoassay. The median amniotic fluid concentration of 5-HETE of women in labor was significantly greater than that of women not in labor (3538 pg/ml vs. 1977 pg/ml, respectively; p = 0.05). This observation is consistent with activation of the lipoxygenase pathway of arachidonic acid metabolism during spontaneous human parturition at term.

Continuous Infusion of Epidural Analgesia in Labor The Effect of Adding Sufentanil to 0.125% Bupivacaine

Forty healthy women in active labor at term had lumbar epidural catheters placed by routine methods. In Group I, an initial 10–15 ml bolus of 0.125% bupivacaine with 2 μg/ml of sufentanil was given followed, 30 minutes later, by an infusion at a rate of 10 ml/hr of 0.125% bupivacaine with 1 μg/ml of sufentanil. In Group II, initial analgesia was produced with 10–15 ml of 0.25% bupivacaine followed by an infusion of 10 ml/hr of 0.125% bupivacaine. Visual analog scales were employed to assess pain relief for the period up to initiation of infusion and then hourly during epidural infusion of both solutions. Additional data elicited included level of sensory analgesia, cardiorespiratory changes, nausea and pruritus incidence, degree of motor blockade, and need for supplemental “top-up” doses of the original bolusing solution. Neonatal status at birth was also assessed.

Continuous Infusion Epidural Analgesia in Labor

The purpose of this study was to determine if the addition of sufentanil would improve the quality of analgesia obtained with 0.125% epidural bupivacaine infusions given to women in active labor. Forty healthy laboring women were randomly assigned to two equal groups. Group 1 had epidural analgesia instituted with the bolus injection of 10-15 ml 0.125% bupivacaine containing sufentanil 2 micrograms/ml, followed 30 minutes later by initiation of an epidural infusion of 0.125% bupivacaine containing sufentanil 1 microgram/ml at a rate of 10 ml/hr. Group 2 had epidural analgesia instituted with 10 or 15 ml of 0.25% bupivacaine with an epidural infusion of 0.125% bupivacaine begun 30 minutes later at a rate of 10 ml/hr. Infusion rates were altered as required to maintain an analgesic level to the tenth thoracic dermatome. Analgesia assessed by visual analog pain scores was significantly better in group 1. Significantly fewer epidural injections were required in group 1, and less motor weakness occurred in these patients. The addition of sufentanil to epidural bupivacaine infusions given in labor improves analgesia and reduces "top-up" requirements.

Evidence for a local change in the progesterone/ estrogen ratio in human parturition at term

The purpose of this study was to determine if a local change in the concentrations of estrogen and progesterone occurs in the amniotic fluid during human parturition at term. Amniotic fluid was retrieved from 20 women in active labor and from 20 women not in labor. Patients were matched for maternal age and gestational age. Estradiol, estriol, progesterone, and dehydroepiandrosterone sulfate were measured in amniotic fluid by radioimmunoassay. For women in active labor, the median concentrations (range) of these steroid hormones were 2.4 ng/ml (1 to 9.2 ng/ml), 1661.2 ng/ml (556.6 to 3928.1 ng/ml), 12.3 ng/ml (4.7 to 41.4 ng/ml), and 187.5 ng/ml (61.2 to 470 ng/ml), respectively. The median concentrations (range) for women not in labor were 1.6 ng/ml (0.3 to 5.7 ng/ml), 684.2 ng/ml (70.6 to 2103.1 ng/ml), 13.2 ng/ml (7.5 to 63 ng/ml), and 65.6 ng/ml (20 to 334 ng/ml), respectively. Thus spontaneous human parturition at term was associated with significantly increased amniotic fluid concentrations of estradiol, estriol, and dehydroepiandrosterone sulfate (p = 0.02, p = 0.002, p = 0.003, respectively). The progesterone/estrogen ratios (progesterone/estradiol and progesterone/estriol) were significantly lower for women in active labor compared with those not in labor (p = 0.002 and p = 0.0006, respectively). We conclude that a local change in the progesterone/estrogen ratio occurs during human parturition at term.

Increased amniotic fluid leukotriene C4 concentration in term human parturition

The purpose of this study was to determine whether parturition is associated with changes in the amniotic fluid concentration of leukotriene C4, an arachidonate lipoxygenase metabolite. Amniotic fluid was collected from 36 women not in labor and from 30 women in active labor with cervical dilation of greater than or equal to 6 cm. The concentration of leukotriene C4 was determined by radioimmunoassay. The median amniotic fluid concentration of leukotriene C4 was greater in laboring women than in nonlaboring women: 121 pg/ml (range, 52 to 261 pg/ml) versus 73.5 pg/ml (range, 6 to 249 pg/ml), respectively (p = 0.0008). These data are consistent with activation of the lipoxygenase pathway during spontaneous parturition at term.

The epidural test dose in obstetrics: is it necessary?

One must distinguish between what is medically safe and what is legally safe. The authors have the impression that in order to be "legally safe" one must perform a test dose. This is despite the fact that it has not been conclusively shown that the use of test doses improve the safety margin of epidural anaesthesia, when administered by a competent person, with the proper resuscitative equipment immediately available. Until a controlled study is performed, test doses should be done for continuous epidural anaesthesia with the understanding that they are neither 100 per cent sensitive nor specific in preventing complications. It is however one more manoeuvre that may be useful in recognizing some of the patients with accidental subarachnoid placement of epidural catheters. The literature suggests that lidocaine 1.5 per cent in dextrose 7.5 per cent should be the test dose of choice in obstetric epidural anaesthesia in an amount known to produce spinal anaesthesia (30-50 mg). The use of epinephrine in test doses in unpremedicated healthy women in active labour is neither sensitive nor specific in signalling intravascular injection, and it may also be detrimental to fetal wellbeing. Epinephrine 15 micrograms as a test dose for intravenous injection appears to create more problems than it solves.