Prelabour uterine rupture: characteristics and outcomes.

OBJECTIVE: To describe the characteristics and outcomes of prelabour uterine ruptures. DESIGN: Descriptive study based on population data from the Medical Birth Registry of Norway, the Patient Administration System and medical records. SAMPLE: Maternities with uterine rupture before start of labour in Norway during the period 1967-2008 (8 complete ruptures among 2 334 712 women with unscarred uteri, and 22 complete and 45 partial ruptures among 121 085 women with scarred uteri). METHOD: We measured the rate of perinatal deaths and peripartum hysterectomy following ruptures. In addition, we studied the characteristics of ruptures. RESULTS: The eight complete ruptures in women with unscarred uteri were associated with trauma from traffic accidents (n = 3; 37.5%), previous curettage (n = 3; 37.5%) and congenital uterine malformations (n = 2; 25%), resulting in seven perinatal deaths and two hysterectomies. The 22 complete ruptures in scarred uteri were mostly outside the lower uterine segment (n = 17; 72.7%). Abnormally invasive placenta (AIP) and previous rupture were present in four (18.2%) and three women (13.6%), respectively. They resulted in nine perinatal deaths (39.1%) and two hysterectomies (9.1%). The 45 partial ruptures involved mostly scars in the lower uterine segment (n = 39; 86.7%). None of them resulted in perinatal death or hysterectomy. Perinatal deaths have decreased dramatically in recent years, despite increasing prelabour rupture rates. CONCLUSION: Although complete uterine ruptures before labour start were rare, they often resulted in catastrophic outcomes, such as perinatal death. Scars outside the lower segment were associated with a higher percentage of catastrophic prelabour ruptures compared with scars in the lower segment (Video S1). TWEETABLE ABSTRACT: Complete prelabour uterine ruptures were rare, but resulted in high perinatal deaths, especially if they were in scars outside the lower segment.

Uterine rupture: trends over 40 years.

OBJECTIVE: To follow trends of uterine rupture over a period of 40 years in Norway. DESIGN: Population-based study using data from the Medical Birth Registry, the Patient Administration System, and medical records. SETTING: Norway. SAMPLE: Women giving birth in 21 maternity units in Norway during the period 1967-2008 (n = 1 441 712 maternities). METHODS: The incidence and outcomes of uterine rupture were compared across four decades: 1967-1977; 1978-1988; 1989-1999; and 2000-2008. Multivariable logistic regression was used to determine the odds ratio (OR) for uterine rupture in each decade compared with the second decade. MAIN OUTCOME MEASURE: Trends in uterine rupture. RESULTS: We identified 359 uterine ruptures. The incidence rates per 10 000 maternities in the first, second, third, and fourth decade were 1.2, 0.9, 1.7, and 6.1, respectively. The ORs for complete and partial ruptures in the fourth versus the second decade were 6.4 (95% confidence interval, 95% CI 3.8-10.8) and 7.2 (95% CI 4.2-12.3), respectively. Significant contributing factors to this increase were the higher rates of labour augmentation with oxytocin, scarred uteri from a previous caesarean section, and labour induction with prostaglandins or prostaglandins combined with oxytocin. After adjusting for risk factors, the ORs for complete and partial ruptures were 2.2 (95% CI 1.3-3.8) and 2.8 (95% CI 1.6-4.8), respectively. Severe postpartum haemorrhage, hysterectomy, intrapartum death and infant death after complete uterine ruptures decreased significantly over time. CONCLUSIONS: A sharply increasing trend of uterine rupture was found. Obstetric interventions contributed to this increase, but could not explain it entirely. TWEETABLE ABSTRACT: A sharply increasing trend of uterine ruptures has been found in Norway in recent years.

Uterine rupture after previous caesarean section.

OBJECTIVE: To determine the risk factors, percentage and maternal and perinatal complications of uterine rupture after previous caesarean section. DESIGN: Population-based registry study. POPULATION: Mothers with births > or =28 weeks of gestation after previous caesarean section (n = 18 794), registered in the Medical Birth Registry of Norway, from 1 January 1999 to 30 June 2005. METHODS: Associations of uterine rupture with risk factors, maternal and perinatal outcome were estimated using cross-tabulations and logistic regression. MAIN OUTCOME MEASURE: Odds of uterine rupture. RESULTS: A total of 94 uterine ruptures were identified (5.0/1000 mothers). Compared with elective prelabour caesarean section, odds of rupture increased for emergency prelabour caesarean section (OR: 8.63; 95% CI: 2.6-28.0), spontaneous labour (OR: 6.65; 95% CI: 2.4-18.6) and induced labour (OR: 12.60; 95% CI: 4.4-36.4). The odds were increased for maternal age > or =40 years versus <30 years (OR: 2.48; 95% CI: 1.1-5.5), non-Western (mothers born outside Europe, North America or Australia) origin (OR: 2.87; 95% CI: 1.8-4.7) and gestational age > or =41 weeks versus 37-40 weeks (OR: 1.73; 95% CI: 1.1-2.7). Uterine rupture after trial of labour significantly increased severe postpartum haemorrhage (OR: 8.51; 95% CI: 4.6-15.1), general anaesthesia exposure (OR: 14.20; 95% CI: 9.1-22.2), hysterectomy (OR: 51.36; 95% CI: 13.6-193.4) and serious perinatal outcome (OR: 24.51 (95% CI: 11.9-51.9). Induction by prostaglandins significantly increased the odds for uterine rupture compared with spontaneous labour (OR: 2.72; 95% CI: 1.6-4.7). Prelabour ruptures occurred after latent uterine activity or abdominal pain in mothers with multiple or uncommon uterine scars. CONCLUSION: Trial of labour carried greater risk and graver outcome of uterine rupture than elective repeated caesarean section, although absolute risks were low. A review of labour management and induction protocol is needed.

Prevalence and risk factors of severe obstetric haemorrhage.

OBJECTIVE: To determine the prevalence, causes, risk factors and acute maternal complications of severe obstetric haemorrhage. DESIGN: Population-based registry study. POPULATION: All women giving birth (307,415) from 1 January 1999 to 30 April 2004 registered in the Medical Birth Registry of Norway. Information about socio-economic risk factors was obtained from Statistics Norway. METHODS: Cross-tabulation was used to study prevalence, causes and acute maternal complications of severe obstetric haemorrhage. Associations of severe obstetric haemorrhage with demographic, medical and obstetric risk factors were estimated using multiple logistic regression models. MAIN OUTCOME MEASURE: Severe obstetric haemorrhage (blood loss of > 1500 ml or blood transfusion). RESULTS: Severe obstetric haemorrhage was identified in 3501 women (1.1%). Uterine atony, retained placenta and trauma were identified causes in 30, 18 and 13.9% of women, respectively. The demographic factors of a maternal age of > or =30 years and South-East Asian ethnicity were significantly associated with an increased risk of haemorrhage. The risk was lower in women of Middle Eastern ethnicity, more than three and two times higher for emergency caesarean delivery and elective caesarean than for vaginal birth, respectively, and substantially higher for multiple pregnancies, von Willebrand's disease and anaemia (haemoglobin <9 g/dl) during pregnancy. Admissions to an intensive care unit, postpartum sepsis, hysterectomy, acute renal failure and maternal deaths were significantly more common among women with severe haemorrhage. CONCLUSION: The high prevalence of severe obstetric haemorrhage indicates the need to review labour management procedures. Demographic and medical risk factors can be managed with extra vigilance.