Carolyn A. Cameron

Increased postpartum hemorrhage rates in Australia

Objective: To determine whether changes in risk factors for postpartum hemorrhage (PPH) over time are associated with a rise in postpartum hemorrhage rates. Methods: Population‐based study using linked hospital discharge and birth records from New South Wales, Australia for 752,374 women giving birth, 1994–2002. Analyses include a description of trends and regression analysis of risk factors for postpartum hemorrhage and comparison of predicted and observed rates of postpartum hemorrhage over time. Results: Increasing proportions of women aged 35 years or older, born overseas, nulliparous, having cesarean births, having inductions and/or epidurals, postterm deliveries and large babies were evident. Observed postpartum hemorrhage rates increased from 4.7 to 6.0 per 100 births (P < 0.001) while expected rates, adjusted for covariates, remained steady (P = 0.28). Conclusion: Increases in postpartum hemorrhage are not explained by the changing risk profile of women. It may be that changes in management and/or reporting of postpartum hemorrhage have resulted in higher postpartum hemorrhage rates.

Measuring maternal morbidity in routinely collected health data: development and validation of a maternal morbidity outcome indicator.

Background:As maternal deaths become rare in many countries, severe maternal morbidity has been suggested as a better indicator of quality of care. Objective:To develop and validate an indicator for measuring major maternal morbidity in routinely collected population health datasets (PHDS). Methods:First, diagnoses and procedures that might indicate major maternal morbidity were compiled and used to sample possible cases in PHDS; second, a validation study of indicated cases was undertaken by review of birth admission medical records using a nested case-control study approach with 400 possible cases and 800 controls; finally “true” morbidity from the validation study was used to define a maternal morbidity outcome indicator (MMOI) with a high positive predictive value (PPV). Sensitivity, specificity, PPV, negative predictive value (NPV), and exact 95% confidence intervals (95% CI) were weighted by the sampling probabilities. Results:There were 1184 records available for review. Of 393 possible cases only 188 were confirmed as suffering major morbidity (weighted PPV 47.3%, sensitivity 72.9%) and of the 791 initial noncases, 787 were confirmed as noncases (weighted NPV 99.5%, specificity 98.5%). Revision of the initial indicator with exclusion of noncontributing International Classification of Disease (ICD) codes provided a MMOI with population-weighted rate of 1.5%, PPV 94.6% (95% CI: 72.3–99.9), sensitivity 78.4% (95% CI: 55.2–93.1), specificity 99.9% (95% CI: 99.5–99.9), and 99.5% agreement with “true” morbidity (kappa 0.86). Conclusions:PHDS can be used reliably to identify women who suffer a major adverse outcome during the birth admission and have potential for monitoring the quality of obstetric care in a uniform and cost-effective way.

Trends in postpartum haemorrhage

Objective: To assess trends and outcomes of postpartum haemorrhage (PPH) in New South Wales (NSW).

Delayed versus early pushing in women with epidural analgesia: a systematic review and meta-analysis

Epidural analgesia is highly effective in relieving the pain of labour and childbirth, but it also interferes with the normal mechanism of labour. Trials of delayed pushing have occurred in response to concerns about the association between epidural analgesia and unwanted and potentially harmful outcomes, particularly instrumental delivery. Instrumental deliveries, especially forceps, have been associated with increased risk of urinary and faecal incontinence, sexual problems and organ prolapse. The mechanism for the association between epidural analgesia and increased instrumental deliveries is likely to be multifactorial but may include a weakened desire to push due to diminution of the bearing down reflex, reduced uterine activity and altered clinical practice. Contemporary obstetric practice has women begin pushing as soon as the cervix is fully dilated. Delaying the onset of pushing has been proposed as an alternative that may allow spontaneous descent and rotation of the fetal head, thereby reducing the instrumental delivery rate. On the other hand, delayed pushing prolongs the second stage of labour and this too has been implicated in pelvic floor trauma and subsequent maternal morbidity. Further, second stage is considered to be a time of particular risk to the fetus. A systematic review and meta-analysis of three small studies published in 1992 found both a tendency towards decreased perineal trauma and a decrease in rotational forceps with a policy of delayed pushing, however, there were insufficient data on infant outcomes and no data on pelvic floor morbidity. Since then several more trials of delayed pushing have been published and we undertook to update the systematic review and metaanalysis with the aim of assessing the effectiveness of delayed pushing among women with epidural analgesia in reducing instrumental deliveries and on other measures of maternal and infant morbidity. We aimed to compare the potential benefits and harms of a policy of delayed pushing among women with uncomplicated pregnancies and effective epidural analgesia established in the first stage of labour.

The prevalence of maternal medical conditions during pregnancy and a validation of their reporting in hospital discharge data.

Population health datasets are a valuable resource for studying maternal and obstetric health outcomes. However, their validity has not been thoroughly examined. We compared medical records from a random selection of New South Wales (NSW) women who gave birth in a NSW hospital in 2002 with coded hospital discharge records. We estimated the population prevalence of maternal medical conditions during pregnancy and found a tendency towards underreporting although specificities were high, indicating that false positives were uncommon.

A meta-analysis of upright positions in the second stage to reduce instrumental deliveries in women with epidural analgesia

Background.  Epidural analgesia is associated with an increased risk of instrumental delivery. We, in this study, present a systematic review in order to assess the effectiveness of maintaining an upright position during the second stage of labor to reduce instrumental deliveries among women choosing epidural analgesia. The study population included women with uncomplicated pregnancies at term with epidural analgesia established in the first stage of labor.

Getting an evidence‐based post‐partum haemorrhage policy into practice

Background:  Post‐partum haemorrhage (PPH) is a potentially life‐threatening complication of childbirth occurring in up to 10% of births. The NSW Department of Health (DoH) issued a new evidence‐based policy (Framework for Prevention, Early Recognition and Management of Post‐partum Haemorrhage) in November 2002. Feedback from maternity units indicated that there were deficiencies in the skills and experience is needed to develop the written protocols and local plans of action required by the Framework.

Birth outcomes for teenage women in New South Wales, 1998-2003.

Background:  Pregnancy and childbirth in teenage women are associated with obstetric and social risks, and there is evidence that the birth rate among teenagers in rural and remote areas of Australia is not in decline. The combination of non‐urban residence and young age at delivery might define a subgroup of women at special risk of adverse birth outcomes.

Outcomes of external cephalic version and breech presentation at term, an audit of deliveries at a Sydney tertiary obstetric hospital, 1997-2004.

Background. Probabilistic information on outcomes of breech presentation is important for clinical decision‐making. We aim to quantify adverse maternal and fetal outcomes of breech presentation at term. Methods. We conducted an audit of 1,070 women with a term, singleton breech presentation who were classified as eligible or ineligible for external cephalic version or diagnosed in labor at a tertiary obstetric hospital in Australia, 1997–2004. Maternal, delivery and perinatal outcomes were assessed and frequency of events quantified. Results. Five hundred and sixty (52%) women were eligible and 170 (16%) were ineligible for external cephalic version, 211 (20%) women were diagnosed in labor and 134 (12%) were unclassifiable. Seventy‐one percent of eligible women had an external cephalic version, with a 39% success rate. Adverse outcomes of breech presentation at term were rare: immediate delivery for prelabor rupture of membranes (1.3%), nuchal cord (9.3%), cord prolapse (0.4%), and fetal death (0.3%); and did not differ by clinical classification. Women who had an external cephalic version had a reduced risk of onset‐of‐labor within 24 h (RR 0.25; 95%CI 0.08, 0.82) compared with women eligible for but who did not have an external cephalic version. Women diagnosed with breech in labor had the highest rates of emergency cesarean section (64%), cord prolapse (1.4%) and poorest infant outcomes. Conclusions. Adverse maternal and fetal outcomes of breech presentation at term are rare and there was no increased risk of complications after external cephalic version. Findings provide important data to quantify the frequency of adverse outcomes that will help facilitate informed decision‐making and ensure optimal management of breech presentation.

Predictors of labor and vaginal birth after cesarean section

Both trial of labor(TOL) and planned cesarean section(CS) have benefits and risks, the relative importance of which vary for individual women w1,2x. Information on the probabilities of outcomes tailored to a person’s risk factors aids decision making w2x. Central to a decision about TOL is considering the probability of successful vaginal birth after cesarean section(VBAC) and the increased risk of morbidity associated with emergency CS. We examined predictors of TOL and VBAC among 24 590 women in New South Wales, Australia 1998–2001, whose previous delivery was a primary CS. Of these women, 9881 (40%) had a TOL, and 5659(23%)gave birth vaginally. Using the ACOG recommendations w3x as a guide, we classified 14 350(58%) women ‘eligible’ for VBAC—that is they had only one previous CS, no medical or obstetric complications and gave birth to a single, live, cephalic presenting infant at