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Medline ® Abstracts for References 30-32

of 'Choosing the route of delivery after cesarean birth'

Severe maternal morbidity in Canada, 1991-2001.
Wen SW, Huang L, Liston R, Heaman M, Baskett T, Rusen ID, Joseph KS, Kramer MS, Maternal Health Study Group, Canadian Perinatal Surveillance System
CMAJ. 2005;173(7):759.
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.
OMNI Research Group, Department of Obstetrics and Gynaecology, Ottawa Health Research Institute, University of Ottawa, Ottawa, Ont. swwen@ohri.ca
Risk factors for uterine rupture and neonatal consequences of uterine rupture: a population-based study of successive pregnancies in Sweden.
Kaczmarczyk M, Sparén P, Terry P, Cnattingius S
BJOG. 2007;114(10):1208.
OBJECTIVE: Uterine rupture is a rare but a catastrophic event. The aim of the present study was to explore the risk factors for uterine rupture and associated neonatal morbidity and mortality among a cohort of Swedish women attempting vaginal birth in their second delivery.
DESIGN: Population-based cohort study.
SETTING: Sweden.
POPULATION: A total of 300,200 Swedish women delivering two single consecutive births between 1983 and 2001.
METHODS: Swedish population-based registers were used to obtain information concerning demographics, pregnancy and birth characteristics, and neonatal outcomes. Logistic regression was used to analyse potential risk factors for uterine rupture and risk of neonatal mortality associated with uterine rupture. Odds ratios were used to estimate relative risks using 95% CI.
MAIN OUTCOME MEASURE: Uterine rupture and neonatal mortality in the second pregnancy.
RESULTS: Compared with women who delivered vaginally in their first birth, women who underwent a caesarean delivery were, during their second delivery, at increased risk of uterine rupture (adjusted OR 41.79; 95% CI 29.73-57.00). Induction of labour, high (>or = 4000 g) birthweight, postterm (>or = 42 weeks) births, high (>or = 35 years) maternal age, and short (<or = 164 cm) maternal stature were also associated with increased risk of uterine rupture. Uterine rupture was associated with a substantially increased risk in neonatal mortality (adjusted OR 65.62; 95% CI 32.60-132.08).
CONCLUSION: The risk of uterine rupture in subsequent deliveries is not only markedly increased among women with a previous caesarean delivery but also influenced by induction of labour, birthweight, gestational age, and maternal characteristics.
Department of Epidemiology, Emory University, School of Public Health, Atlanta, GA 30307, USA. mkaczma@sph.emory.edu
Risk of uterine rupture and adverse perinatal outcome at term after cesarean delivery.
Spong CY, Landon MB, Gilbert S, Rouse DJ, Leveno KJ, Varner MW, Moawad AH, Simhan HN, Harper M, Wapner RJ, Sorokin Y, Miodovnik M, Carpenter M, Peaceman AM, O'Sullivan MJ, Sibai BM, Langer O, Thorp JM, Ramin SM, Mercer BM, National Institute of Child Health and Human Development (NICHD) Maternal-Fetal Medicine Units (MFMU) Network
Obstet Gynecol. 2007;110(4):801.
OBJECTIVE: Current information on the risk of uterine rupture after cesarean delivery has generally compared the risk after trial of labor to that occurring with an elective cesarean delivery without labor. Because antepartum counseling cannot account for whether a woman will develop an indication requiring a repeat cesarean delivery or whether labor will occur before scheduled cesarean delivery, the purpose of this analysis was to provide clinically useful information regarding the risks of uterine rupture and adverse perinatal outcome for women at term with a history of prior cesarean delivery.
METHODS: Women with a term singleton gestation and prior cesarean delivery were studied over 4 years at 19 centers. For this analysis, outcomes from five groups were studied: trial of labor, elective repeat with no labor, elective repeat with labor (women presenting in early labor who subsequently underwent cesarean delivery), indicated repeat with labor, and indicated repeat without labor. All cases of uterine rupture were reviewed centrally to assure accuracy of diagnosis.
RESULTS: A total of 39,117 women were studied. In term pregnant women with a prior cesarean delivery, the overall risk for uterine rupture was 0.32% (125 of 39,117), and the overall risk for serious adverse perinatal outcome (stillbirth, hypoxic ischemic encephalopathy, neonatal death) was 106 of 39,049 (0.27%). The uterine rupture risk for indicated repeat cesarean delivery (labor or without labor) was 7 of 6,080 (0.12%); the risk for elective (no indication) repeat cesarean delivery (labor or without labor) was 4 of 17,714 (0.02%). Indicated repeat cesarean delivery increased the risk of uterine rupture by a factor of 5 (odds ratio 5.1, 95% confidence interval 1.49-17.44). In the absence of an indication, the presence of labor also increased the risk of uterine rupture (4 of 2,721 [0.15%]compared with 0 of 14,993, P<.01). The highest rate of uterine rupture occurred in women undergoing trial of labor (0.74%, 114 of 15,323).
CONCLUSION: At term, the risk of uterine rupture and adverse perinatal outcome for women with a singleton and prior cesarean delivery is low regardless of mode of delivery, occurring in 3 per 1,000 women. Maternal complications occurred in 3-8% of women within the five delivery groups.
National Institute of Child Health and Human Development, Bethesda, Maryland, USA. spongc@mail.nih.gov