BackgroundIn high-income countries, the incidence of severe postpartum hemorrhage (PPH) has increased. This has important public health relevance because severe PPH is a leading cause of major maternal morbidity. However, few studies have identified risk factors for severe PPH within a contemporary obstetric cohort.MethodsWe performed a case-control study to identify risk factors for severe PPH among a cohort of women who delivered at one of three hospitals in Norway between 2008 and 2011. A case (severe PPH) was classified by an estimated blood loss ≥1500 mL or the need for blood transfusion for excessive postpartum bleeding. Using logistic regression, we applied a pragmatic strategy to identify independent risk factors for severe PPH.ResultsAmong a total of 43,105 deliveries occurring between 2008 and 2011, we identified 1064 cases and 2059 random controls. The frequency of severe PPH was 2.5% (95% confidence interval (CI): 2.32–2.62). The most common etiologies for severe PPH were uterine atony (60%) and placental complications (36%). The strongest risk factors were a history of severe PPH (adjusted OR (aOR) = 8.97, 95% CI: 5.25–15.33), anticoagulant medication (aOR = 4.79, 95% CI: 2.72–8.41), anemia at booking (aOR = 4.27, 95% CI: 2.79–6.54), severe pre-eclampsia or HELLP syndrome (aOR = 3.03, 95% CI: 1.74–5.27), uterine fibromas (aOR = 2.71, 95% CI: 1.69–4.35), multiple pregnancy (aOR = 2.11, 95% CI: 1.39–3.22) and assisted reproductive technologies (aOR = 1.88, 95% CI: 1.33–2.65).ConclusionsBased on our findings, women with a history of severe PPH are at highest risk of severe PPH. As well as other established clinical risk factors for PPH, a history of severe PPH should be included as a risk factor in the development and validation of prediction models for PPH.

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 ‡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. ConclusionThe 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.Keywords Prevalence, risk factors, severe obstetric haemorrhage.Please cite this paper as: Al-Zirqi I, Vangen S, Forsen L, Stray-Pedersen B. Prevalence and risk factors of severe obstetric haemorrhage.

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.Keywords Outcome, risk factors, trends, uterine rupture.Tweetable abstract A sharply increasing trend of uterine ruptures has been found in Norway in recent years.

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 ‡28 weeks of gestation after previous caesarean section (n = 18 794), registered in the Medical

Sequential labor induction with prostaglandins and oxytocin and augmentation of labor with oxytocin are important risk factors for complete uterine rupture in intact and scarred uteri.