Robert M. Liston

Maternal mortality and severe morbidity associated with low-risk planned cesarean delivery versus planned vaginal delivery at term

Background: The rate of elective primary cesarean delivery continues to rise, owing in part to the widespread perception that the procedure is of little or no risk to healthy women. Methods: Using the Canadian Institute for Health Informations Discharge Abstract Database, we carried out a retrospective population-based cohort study of all women in Canada (excluding Quebec and Manitoba) who delivered from April 1991 through March 2005. Healthy women who underwent a primary cesarean delivery for breech presentation constituted a surrogate “planned cesarean group” considered to have undergone low-risk elective cesarean delivery, for comparison with an otherwise similar group of women who had planned to deliver vaginally. Results: The planned cesarean group comprised 46 766 women v. 2 292 420 in the planned vaginal delivery group; overall rates of severe morbidity for the entire 14-year period were 27.3 and 9.0, respectively, per 1000 deliveries. The planned cesarean group had increased postpartum risks of cardiac arrest (adjusted odds ratio [OR] 5.1, 95% confidence interval [CI] 4.1–6.3), wound hematoma (OR 5.1, 95% CI 4.6–5.5), hysterectomy (OR 3.2, 95% CI 2.2–4.8), major puerperal infection (OR 3.0, 95% CI 2.7–3.4), anesthetic complications (OR 2.3, 95% CI 2.0–2.6), venous thromboembolism (OR 2.2, 95% CI 1.5–3.2) and hemorrhage requiring hysterectomy (OR 2.1, 95% CI 1.2–3.8), and stayed in hospital longer (adjusted mean difference 1.47 d, 95% CI 1.46–1.49 d) than those in the planned vaginal delivery group, but a lower risk of hemorrhage requiring blood transfusion (OR 0.4, 95% CI 0.2–0.8). Absolute risk increases in severe maternal morbidity rates were low (e.g., for postpartum cardiac arrest, the increase with planned cesarean delivery was 1.6 per 1000 deliveries, 95% CI 1.2–2.1). The difference in the rate of in-hospital maternal death between the 2 groups was nonsignificant (p = 0.87). Interpretation: Although the absolute difference is small, the risks of severe maternal morbidity associated with planned cesarean delivery are higher than those associated with planned vaginal delivery. These risks should be considered by women contemplating an elective cesarean delivery and by their physicians.

Trends in postpartum hemorrhage in high resource countries: a review and recommendations from the International Postpartum Hemorrhage Collaborative Group

AbstractBackgroundPostpartum hemorrhage (PPH) is a major cause of maternal mortality and morbidity worldwide. Several recent publications have noted an increasing trend in incidence over time. The international PPH collaboration was convened to explore the observed trends and to set out actions to address the factors identified.MethodsWe reviewed available data sources on the incidence of PPH over time in Australia, Belgium, Canada, France, the United Kingdom and the USA. Where information was available, the incidence of PPH was stratified by cause.ResultsWe observed an increasing trend in PPH, using heterogeneous definitions, in Australia, Canada, the UK and the USA. The observed increase in PPH in Australia, Canada and the USA was limited solely to immediate/atonic PPH. We noted increasing rates of severe adverse outcomes due to hemorrhage in Australia, Canada, the UK and the USA.ConclusionKey Recommendations 1. Future revisions of the International Classification of Diseases should include separate codes for atonic PPH and PPH immediately following childbirth that is due to other causes. Also, additional codes are required for placenta accreta/percreta/increta.2. Definitions of PPH should be unified; further research is required to investigate how definitions are applied in practice to the coding of data.3. Additional improvement in the collection of data concerning PPH is required, specifically including a measure of severity.4. Further research is required to determine whether an increased rate of reported PPH is also observed in other countries, and to further investigate potential risk factors including increased duration of labor, obesity and changes in second and third stage management practice.5. Training should be provided to all staff involved in maternity care concerning assessment of blood loss and the monitoring of women after childbirth. This is key to reducing the severity of PPH and preventing any adverse outcomes.6. Clinicians should be more vigilant given the possibility that the frequency and severity of PPH has in fact increased. This applies particularly to small hospitals with relatively few deliveries where management protocols may not be defined adequately and drugs or equipment may not be on hand to deal with unexpected severe PPH.

The perinatal effects of delayed childbearing.

OBJECTIVE: To determine if the rates of pregnancy complications, preterm birth, small for gestational age, perinatal mortality, and serious neonatal morbidity are higher among mothers aged 35–39 years or 40 years or older, compared with mothers 20–24 years. METHODS: We performed a population-based study of all women in Nova Scotia, Canada, who delivered a singleton fetus between 1988 and 2002 (N = 157,445). Family income of women who delivered between 1988 and 1995 was obtained through a confidential linkage with tax records (n = 76,300). The primary outcome was perinatal death (excluding congenital anomalies) or serious neonatal morbidity. Analysis was based on logistic models. RESULTS: Older women were more likely to be married, affluent, weigh 70 kg or more, attend prenatal classes, and have a bad obstetric history but less likely to be nulliparous and to smoke. They were more likely to have hypertension, diabetes mellitus, placental abruption, or placenta previa. Preterm birth and small-for-gestational age rates were also higher; compared with women aged 20–24 years, adjusted rate ratios for preterm birth among women aged 35–39 years and 40 years or older were 1.61 (95% confidence interval [CI] 1.42–1.82; P < .001) and 1.80 (95% CI 1.37–2.36; P < .001), respectively. Adjusted rate ratios for perinatal mortality/morbidity were 1.46 (95% CI 1.11–1.92; P = .007) among women 35–39 years and 1.95 (95% CI 1.13–3.35; P = .02) among women 40 years or older. Perinatal mortality rates were low at all ages, especially in recent years. CONCLUSION: Older maternal age is associated with relatively higher risks of perinatal mortality/morbidity, although the absolute rate of such outcomes is low. LEVEL OF EVIDENCE: II-2

Outcomes of planned home birth with registered midwife versus planned hospital birth with midwife or physician

Background: Studies of planned home births attended by registered midwives have been limited by incomplete data, nonrepresentative sampling, inadequate statistical power and the inability to exclude unplanned home births. We compared the outcomes of planned home births attended by midwives with those of planned hospital births attended by midwives or physicians. Methods: We included all planned home births attended by registered midwives from Jan. 1, 2000, to Dec. 31, 2004, in British Columbia, Canada (n = 2889), and all planned hospital births meeting the eligibility requirements for home birth that were attended by the same cohort of midwives (n = 4752). We also included a matched sample of physician-attended planned hospital births (n = 5331). The primary outcome measure was perinatal mortality; secondary outcomes were obstetric interventions and adverse maternal and neonatal outcomes. Results: The rate of perinatal death per 1000 births was 0.35 (95% confidence interval [CI] 0.00–1.03) in the group of planned home births; the rate in the group of planned hospital births was 0.57 (95% CI 0.00–1.43) among women attended by a midwife and 0.64 (95% CI 0.00–1.56) among those attended by a physician. Women in the planned home-birth group were significantly less likely than those who planned a midwife-attended hospital birth to have obstetric interventions (e.g., electronic fetal monitoring, relative risk [RR] 0.32, 95% CI 0.29–0.36; assisted vaginal delivery, RR 0.41, 95% 0.33–0.52) or adverse maternal outcomes (e.g., third- or fourth-degree perineal tear, RR 0.41, 95% CI 0.28–0.59; postpartum hemorrhage, RR 0.62, 95% CI 0.49–0.77). The findings were similar in the comparison with physician-assisted hospital births. Newborns in the home-birth group were less likely than those in the midwife-attended hospital-birth group to require resuscitation at birth (RR 0.23, 95% CI 0.14–0.37) or oxygen therapy beyond 24 hours (RR 0.37, 95% CI 0.24–0.59). The findings were similar in the comparison with newborns in the physician-assisted hospital births; in addition, newborns in the home-birth group were less likely to have meconium aspiration (RR 0.45, 95% CI 0.21–0.93) and more likely to be admitted to hospital or readmitted if born in hospital (RR 1.39, 95% CI 1.09–1.85). Interpretation: Planned home birth attended by a registered midwife was associated with very low and comparable rates of perinatal death and reduced rates of obstetric interventions and other adverse perinatal outcomes compared with planned hospital birth attended by a midwife or physician.

Investigation of an increase in postpartum haemorrhage in Canada

Objective  To investigate the cause of a recent increase in hysterectomies for postpartum haemorrhage in Canada.

Fetal Health Surveillance: Antepartum and Intrapartum Consensus Guideline

OBJECTIVE This guideline provides new recommendations pertaining to the application and documentation of fetal surveillance in the antepartum and intrapartum period that will decrease the incidence of birth asphyxia while maintaining the lowest possible rate of obstetrical intervention. Pregnancies with and without risk factors for adverse perinatal outcomes are considered. This guideline presents an alternative classification system for antenatal fetal non-stress testing and intrapartum electronic fetal surveillance to what has been used previously. This guideline is intended for use by all health professionals who provide antepartum and intrapartum care in Canada. OPTIONS Consideration has been given to all methods of fetal surveillance currently available in Canada. OUTCOMES Short- and long-term outcomes that may indicate the presence of birth asphyxia were considered. The associated rates of operative and other labour interventions were also considered. EVIDENCE A comprehensive review of randomized controlled trials published between January 1996 and March 2007 was undertaken, and MEDLINE and the Cochrane Database were used to search the literature for all new studies on fetal surveillance both antepartum and intrapartum. The level of evidence has been determined using the criteria and classifications of the Canadian Task Force on Preventive Health Care. SPONSOR This consensus guideline was jointly developed by the Society of Obstetricians and Gynaecologists of Canada and the British Columbia Perinatal Health Program (formerly the British Columbia Reproductive Care Program or BCRCP) and was partly supported by an unrestricted educational grant from the British Columbia Perinatal Health Program.

Diagnostic accuracy of urinary spot protein:creatinine ratio for proteinuria in hypertensive pregnant women: systematic review

Objective To review the spot protein:creatinine ratio and albumin:creatinine ratio as diagnostic tests for significant proteinuria in hypertensive pregnant women. Design Systematic review. Data sources Medline and Embase, the Cochrane Library, reference lists, and experts. Review methods Literature search (1980-2007) for articles of the spot protein:creatinine ratio or albumin:creatinine ratio in hypertensive pregnancy, with 24 hour proteinuria as the comparator. Results 13 studies concerned the spot protein:creatinine ratio (1214 women with primarily gestational hypertension). Nine studies reported sensitivity and specificity for eight cut-off points, median 24 mg/mmol (range 17-57 mg/mmol; 0.15-0.50 mg/mg). Laboratory assays were not well described. Diagnostic test characteristics were recalculated for a cut-off point of 30 mg/mmol. No significant heterogeneity in cut-off points was found between studies over a range of proteinuria. Pooled values gave a sensitivity of 83.6% (95% confidence interval 77.5% to 89.7%), specificity of 76.3% (72.6% to 80.0%), positive likelihood ratio of 3.53 (2.83 to 4.49), and negative likelihood ratio of 0.21 (0.13 to 0.31) (nine studies, 1003 women). Two studies of the spot albumin:creatinine ratio (225 women) found optimal cut-off points of 2 mg/mmol for proteinuria of 0.3 g/day or more and 27 mg/mmol for albuminuria. Conclusion The spot protein:creatinine ratio is a reasonable “rule-out” test for detecting proteinuria of 0.3 g/day or more in hypertensive pregnancy. Information on use of the albumin:creatinine ratio in these women is insufficient.

Severe maternal morbidity in Canada, 1991-2001.

Background: Although death rates are often used to monitor the quality of health care, in industrialized countries maternal deaths have become rare. Severe maternal morbidity has therefore been proposed as a supplementary indicator for surveillance of the quality of maternity care. Our purpose in this study was to describe severe maternal morbidity in Canada over a 10-year period, among women with or without major pre-existing conditions. Methods: We carried out a retrospective cohort study of severe maternal morbidity involving 2 548 824 women who gave birth in Canadian hospitals between 1991 and 2000. Thirteen conditions that may threaten the life of the mother (e.g., eclampsia) and 11 major pre-existing chronic conditions (e.g., diabetes) that could be identified from diagnostic codes were noted. Results: The overall rate of severe maternal morbidity was 4.38 per 1000 deliveries. The fatality rate among these women was 158 times that of the entire sample. Rates of venous thromboembolism, uterine rupture, adult respiratory distress syndrome, pulmonary edema, myocardial infarction, severe postpartum hemorrhage requiring hysterectomy, and assisted ventilation increased substantially from 1991 to 2000. The presence of major pre-existing conditions increased the risk of severe maternal morbidity to 6-fold. Interpretation: Severe maternal morbidity occurs in about 1 of 250 deliveries in Canada, with marked recent increases in certain morbid conditions such as pulmonary edema, myocardial infarction, hemorrhage requiring hysterectomy, and the use of assisted ventilation.

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 Informations 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

Socioeconomic status and perinatal outcomes in a setting with universal access to essential health care services

Background: The health care system in Canada provides essential health services to all women irrespective of socioeconomic status. Our objective was to determine whether perinatal and infant outcomes varied by family income and other socioeconomic factors in this setting. Methods: We included all 92 914 women who delivered in Nova Scotia between 1988 and 1995 following a singleton pregnancy. Family income was obtained for 76 440 of these women through a confidential link to income tax records and was divided into 5 groups. Outcomes studied included pregnancy complications, preterm birth, small-for-gestational-age live birth, perinatal death, serious neonatal morbidity, postneonatal death and infant death. Logistic regression models were used to adjust for potential confounders. Results: Compared with women in the highest family income group, those in the lowest income group had significantly higher rates of gestational diabetes (crude rate ratio [RR] 1.44, 95% confidence interval [CI] 1.21–1.73), preterm birth (crude RR 1.20, 95% CI 1.06–1.35), small-for-gestational-age live birth (crude RR 1.81, 95% CI 1.66–1.97) and postneonatal death (crude RR 5.54, 95% CI 2.21–13.9). The opposite was true for rates of perinatal death (crude RR 0.74, 95% CI 0.56–0.96), and there was no significant difference between the 2 groups in the composite of perinatal death or serious neonatal morbidity (crude RR 1.01, 95% CI 0.82–1.24). Adjustment for behavioural and lifestyle factors accentuated or attenuated socioeconomic differences. Interpretation: Lower family income is associated with increased rates of gestational diabetes, small-for-gestational-age live birth and postneonatal death despite health care services being widely available at no out-of-pocket expense.