PubMed Health⌕ Search

Biomedical subjects

Robert M Liston

Publications and source records attributed to Robert M Liston.

9 recordsLinked to original sources
PubMed2006

Epidural analgesia associated with low-dose oxytocin augmentation increases cesarean births: a critical look at the external validity of randomized trials.

OBJECTIVE: Randomized controlled trials suggest epidural analgesia (EA) does not increase the frequency of cesarean births compared with opioid analgesia. We analyzed trials comparing EA with opioid analgesia to determine their external validity in contemporary North American practice. STUDY DESIGN: Randomized controlled trials comparing EA with opioid analgesia were identified from the Cochrane database and Medline and included if they reported labor outcomes and management protocols. Labor management was then compared with current obstetric practice determined from surveys of North American teaching maternity units and clinical practice guidelines. RESULTS: Of 19 trials identified, 8 were included. Seven trials used Active Management of Labor protocols that used high-dose oxytocin; each demonstrated no epidural-related increase in cesarean births. One trial that used low-dose oxytocin demonstrated a marked increase in cesarean births. Most large North American obstetric units use low-dose oxytocin. CONCLUSION: Randomized trials showing no effect of EA on cesarean section (CS) rate lack external validity in much of North American practice. The limited data available suggest EA and low-dose oxytocin used together increase the CS rate. Early detection of dystocia and high-dose oxytocin augmentation should be considered for women receiving EA; those delivering in low-dose oxytocin settings should be advised of a probable increase in the likelihood of CS.

Analgesia, Epidural↗
PubMed2006

Socioeconomic status and receipt of obstetric services in Canada.

OBJECTIVE: To examine differences in labor induction and cesarean delivery rates by socioeconomic status in Nova Scotia, Canada. METHODS: We studied all women in Nova Scotia who delivered between 1988 and 1995 after a singleton pregnancy. Information was obtained from the Nova Scotia Atlee Perinatal Database and the federal income tax (T1) Family Files maintained by the Small Area and Administrative Data Division of Statistics Canada (n = 76,440). Labor induction and cesarean delivery rates were contrasted by family income and other indices, with adjustment for risk factors carried out using logistic models. RESULTS: Maternal characteristics and other factors varied by socioeconomic status; in the lowest income group 4.4% of women were aged 35 years or older, and 49.4% were nonsmokers, whereas in the highest income group 17.7% were aged 35 years or older, and 88.7% were nonsmokers. Crude induction rates were similar across income groups (17.7% compared with 18.1% in the lowest compared with highest income groups), but there were significant differences in crude cesarean (17.7% compared with 21.2%) and crude primary cesarean rates (12.5% compared with 17.0%). Controlling for differences in risk factors altered these relationships. Adjusted rate ratios, 95% confidence intervals (CIs) and P values contrasting the lowest compared with highest income groups were labor induction 1.09 (95% CI 1.00-1.19), P = .05; overall cesarean delivery 1.12 (95% CI 1.03-1.23), P = .01; primary cesarean delivery 1.09 (95% CI 0.98-1.21), P = .12. CONCLUSION: Affluent women in Canada are not more likely to have labor induction or cesarean delivery compared with less affluent women. LEVEL OF EVIDENCE: II-2.

Adult↗
PubMed2006

Early labor assessment and support at home versus telephone triage: a randomized controlled trial.

OBJECTIVE: To compare rates of cesarean delivery among women who were triaged by obstetric nurses, either by telephone or by means of home visits. METHODS: Healthy, nulliparous women in labor at term with uncomplicated pregnancies residing in the City of Vancouver, British Columbia, and suburbs between November 2001 and October 2004 were randomized when they sought advice about when to come to hospital. Women randomized to telephone triage (n=731) were provided with advice by telephone. Women randomized to a home visit (n=728) were triaged after a "hands-on" assessment in their homes. RESULTS: The relative risk (RR) for cesarean delivery among home-triaged women compared with those receiving only telephone support was 1.12 (95% confidence interval [CI] 0.94-1.32). The study was designed to have 80% power to detect a RR less than 0.78 or greater than 1.27 for cesarean delivery. Significantly fewer women in the home visit group were admitted to hospital with cervical dilatation at 3 cm or less (RR 0.85, 95% CI 0.76-0.94). Significantly more women in the home visit group managed their labor without a visit to hospital for assessment (RR 1.54, 95% CI 1.23-1.92). There were no statistically significant differences in use of narcotic analgesia, epidural analgesia, and augmentation of labor. Adverse neonatal outcomes were rare and did not differ between study groups. CONCLUSION: Early labor assessment and support at home versus support by telephone reduces the number of visits to hospital in latent phase labor but does not impact cesarean delivery rates among healthy nulliparous women. CLINICAL TRIAL REGISTRATION: ISRCTN, www.controlled-trials.com/isrctn, MCT-44153 LEVEL OF EVIDENCE: I.

Adult↗
PubMed2006

Predictors of cesarean section following elective post-dates induction of labor in nullipara with uncomplicated singleton vertex pregnancies.

OBJECTIVE: Although post-dates is among the most common indications for induction of labor, no studies have identified the predictors of cesarean section (C/S) in that population. The high cesarean rate in our institution for this group of women triggered us to assess different induction practices to elicit potential causes. METHODS: We conducted a hospital-based retrospective cohort analysis using chart reviews of all nullipara women with induced labor at the Children's and Women's Health Centre of British Columbia, Vancouver, Canada, during the 2-year period, April 1998 to March 2000. The C/S rate was compared among 3 groups of women who were divided according to their induction method. RESULTS: Three hundred and thirty-nine women meeting the inclusion criteria were induced. Of the 25 women who received oxytocin ideally and the 111 women who did not, 7 (28%) and 53 (48%) were delivered by C/S, (x2=3.228 p=0.07; relative risks 0.59 [95% confidence interval 0.30, 1.13]). A significantly lower C/S rate (x2=21.9, p<0.0005) was found among women induced with prostaglandin (PG) alone (19.4%) compared with those induced with PG and oxytocin, whether oxytocin was given ideally (38.3%) or not ideally (45.4%). Of women who received oxytocin, there was no difference in chorioamnionitis (x2=0.485, p=0.49) between those who had an early membrane rupture (with or pre-oxytocin, 22.4%) and those who had membrane rupture following a period of oxytocin infusion (18.5%). CONCLUSION: The need for oxytocin or less than 2 doses of PG is associated with increased risk of C/S. Whether oxytocin was given according to protocol (ideally) or not, made no difference to the C/S risk in this population.

Adult↗
PubMed2005

Variations in early and intermediate neonatal outcomes for inborn infants admitted to a Canadian NICU and born of hypertensive pregnancies.

OBJECTIVE: To determine whether neonatal intensive care unit (NICU) outcomes vary by centre for inborn neonates of hypertensive pregnancies and, if so, whether that variation might be related to between-centre variations in obstetric practice. METHODS: The study comprised a prospective cohort of 13 505 singleton neonates admitted to 17 Canadian NICUs. Adjusting for potential confounders, we used multivariate regression to analyze the relation between centre of delivery and 6 dependent variables: (1) Apgar score < 7 at 5 minutes; (2) Score of Neonatal Acute Physiology-II (SNAP-II) score > or = 10; (3) neonatal death; (4) neonatal death or morbidity (owing to bronchopulmonary dysplasia [BPD], intraventricular hemorrhage [IVH], necrotizing enterocolitis [NEC], persistent ductus arteriosus [PDA], or periventricular leukomalacia [PVL]); (5) BPD alone; and (6) major neonatal morbidity (that is, at least one of IVH, PVL, NEC, or PDA). NICU practices known to influence these outcomes were included in the modelling for neonatal death and neonatal morbidity. In a sensitivity analysis for practice variation, antenatal steroid exposure was both included and excluded in each regression. RESULTS: For 5 of the 6 dependent variables, we identified between-centre variation that was not explained solely by variation in antenatal corticosteroid use. Adjusted odds ratios varied from 0.11 to 5.6 (the reference centre was the median rate of the adverse outcome). CONCLUSIONS: In the pregnancy hypertension setting, between-centre variations in practice are associated with variations in neonatal physiology and survival. For infants admitted to NICU, the obstetric management of hypertensive pregnancies appears to have an effect on both short- and medium-term neonatal outcomes, even after correction for NICU management.

Adrenal Cortex Hormones↗
PubMed2005

Risk of maternal postpartum readmission associated with mode of delivery.

OBJECTIVE: To determine whether cesarean and operative vaginal deliveries are associated with an increased risk of maternal rehospitalization compared with spontaneous vaginal delivery. METHODS: A population-based cohort study was conducted by using the Canadian Institute for Health Information's Discharge Abstract Database between 1997/1998 and 2000/2001, which included 900,108 women aged 15-44 years with singleton live births (after excluding several selected obstetric conditions). RESULTS: A total of 16,404 women (1.8%) were rehospitalized within 60 days after initial discharge. Compared with spontaneous vaginal delivery (rate 1.5%), cesarean delivery was associated with a significantly increased risk of postpartum readmission (rate 2.7%, odds ratio [OR] 1.9, 95% confidence interval [CI] 1.8-1.9); ie, there was 1 excess postpartum readmission per 75 cesarean deliveries. Diagnoses associated with significantly increased risks of readmission after cesarean delivery (compared with spontaneous vaginal delivery) included pelvic injury/wounds (rate 0.86% versus 0.06%, OR 13.4, 95% CI 12.0-15.0), obstetric complications (rate 0.23% versus 0.08%, OR 3.0, 95% CI 2.6-3.5), venous disorders and thromboembolism (rate 0.07% versus 0.03%, OR 2.7, 95% CI 2.1-3.4), and major puerperal infection (rate 0.45% versus 0.27%, OR 1.8, 95% CI 1.6-1.9). Women delivered by forceps or vacuum were also at an increased risk of readmission (rates 2.2% and 1.8% versus 1.5%; OR forceps: 1.4, 95% CI 1.3-1.5; OR vacuum: 1.2, 95% CI 1.2-1.3, respectively). Higher readmission rates after operative vaginal delivery were due to pelvic injury/wounds, genitourinary conditions, obstetric complications, postpartum hemorrhage, and major puerperal infection. CONCLUSION: Compared with spontaneous vaginal delivery, cesarean delivery, and operative vaginal delivery increase the risk of maternal postpartum readmission. LEVEL OF EVIDENCE: II-2.

Adolescent↗
PubMed2004

Infant mortality among First Nations versus non-First Nations in British Columbia: temporal trends in rural versus urban areas, 1981-2000.

BACKGROUND: Increasingly more First Nations (FN) people have moved from rural to urban areas. It is unknown how disparities in infant mortality among FN versus non-FN women have changed over time in urban versus rural areas. METHODS: We conducted a birth cohort-based study of all 877 925 live births (56 771 FN and 821 154 non-FN) registered in British Columbia, 1981-2000. Main outcomes included rates, risk differences, and relative risks of neonatal, postneonatal, and overall infant death. RESULTS: Both neonatal and postneonatal mortality rates for FN infants showed a steady decline in rural areas but a rise-and-fall pattern in urban areas. Relative risks for overall infant death among FN versus non-FN infants declined steadily from 2.75 (95% CI: 2.04, 3.72) to 1.87 (95% CI: 1.24, 2.81) in rural areas from 1981-1984 to 1997-2000, but rose from 1.59 (95% CI: 1.27, 1.99) (1981-1984) to 2.80 (2.33-3.37) (1989-92) and then fell to 1.89 (1.44-2.49) (1997-2000) in urban areas. Risk differences for neonatal death among FN versus non-FN infants declined substantially over time in rural but not urban areas. The disparities in neonatal death among FN versus non-FN were largely explained by differences in preterm birth, while the disparities in postneonatal death were not explained by observed maternal and pregnancy characteristics. CONCLUSIONS: Reductions in disparities in infant mortality among FN versus non-FN women have been less substantial and consistent over time in urban versus rural areas of British Columbia, suggesting the need for greater attention to FN maternal and infant health in urban areas.

Adult↗
PubMed2004

Disparities in birth outcomes by neighborhood income: temporal trends in rural and urban areas, british columbia.

BACKGROUND: Knowledge of socioeconomic disparities in health is of interest to both the general public and public health policymakers. It is unclear how disparities in birth outcomes by socioeconomic status have changed over time, particularly in settings with universal health insurance and favorable socioeconomic conditions. METHODS: We identified a cohort of all births (n = 713,950) registered in British Columbia, 1985-2000. We compared rates and relative risks (RRs) of preterm birth, small-for-gestational-age (SGA), stillbirth, and neonatal and postneonatal death across neighborhood-income quintiles from Q1 (richest, the reference) to Q5 (poorest) by 4-year intervals in rural and urban areas. Logistic regression was used to control for maternal and pregnancy characteristics. RESULTS: Maternal characteristics varied widely across neighborhood-income quintiles in both rural and urban areas. There were moderate and persistent disparities in birth outcomes across neighborhood-income quintiles in urban but not rural areas. The relative disparities in urban areas did not diminish over time for all birth outcomes and actually rose for postneonatal mortality. For example, crude RRs (95% confidence intervals) for Q5 versus Q1 in urban areas for SGA were 1.44 (1.37-1.52) in 1985-1988 and 1.41 (1.33-1.49) in 1997-2000; for postneonatal death, the corresponding results were 1.61 (1.17-2.20) and 2.20 (1.24-3.92), respectively. Most of the observed disparities could not be explained by observed maternal and pregnancy characteristics. CONCLUSION: Moderate disparities in birth outcomes by neighborhood income persist in urban areas (although not rural areas) of British Columbia, despite a universal health insurance system and generally favorable socioeconomic conditions.

British Columbia↗