Lisa Forsén

Risk factors for complete uterine rupture.

BACKGROUND: Complete uterine rupture is a rare peripartum complication associated with a catastrophic outcome. Because of its rarity, knowledge about its risk factors is not very accurate. Most previous studies were small and over a limited time interval. Moreover, international diagnostic coding was used in most studies. These codes are not able to differentiate between the catastrophic complete type and less catastrophic partial type. Complete uterine rupture is expected to increase as the rate of cesarean delivery increases. Thus, we need more accurate knowledge about the risk factors for this complication. OBJECTIVE: The objective of the study was to estimate the incidence and risk factors for complete uterine rupture during childbirth in Norway. STUDY DESIGN: This population‐based study included women that gave birth after starting labor in 1967–2008. Data were from the Medical Birth Registry of Norway and Patient Administration System, complemented with information from medical records. We included 1,317,967 women without previous cesarean delivery and 57,859 with previous cesarean delivery. The outcome was complete uterine rupture (tearing of all uterine wall layers, including serosa and membranes). Risk factors were parameters related to demographics, pregnancy, and labor. Odds ratios for complete uterine rupture were computed with crude logistic regressions for each risk factor. Separate multivariable logistic regressions were performed to calculate the adjusted odds ratios and 95% confidence intervals. RESULTS: Complete uterine rupture occurred in 51 cases without previous cesarean delivery (0.38 per 10,000) and 122 with previous cesarean delivery (21.1 per 10,000). The strongest risk factor was sequential labor induction with prostaglandins and oxytocin, compared with spontaneous labor, in those without previous cesarean delivery (adjusted odds ratio, 48.0, 95% confidence interval, 20.5–112.3) and those with previous cesarean delivery (adjusted odds ratio, 16.1, 95% confidence interval, 8.6–29.9). Other significant risk factors for those without and with previous cesarean delivery, respectively, included labor augmentation with oxytocin (adjusted odds ratio, 22.5, 95% confidence interval, 10.9–41.2; adjusted odds ratio, 4.4, 95% confidence interval, 2.9–6.6), antepartum fetal death (adjusted odds ratio, 15.0, 95% confidence interval, 6.2–36.6; adjusted odds ratio, 4.0, 95% confidence interval, 1.1–14.2), and previous first‐trimester miscarriages (adjusted odds ratio, 9.6, 95% confidence interval, 5.7–17.4; adjusted odds ratio, 5.00, 95% confidence interval, 3.4–7.3). After a previous cesarean delivery, the risk of rupture was increased by an interdelivery interval <16 months (adjusted odds ratio, 2.3; 95% confidence interval, 1.1–5.4) and a previous cesarean delivery with severe postpartum hemorrhage (adjusted odds ratio, 5.6; 95% confidence interval, 2.4–13.2). CONCLUSION: 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.

Maternal age and emergency operative deliveries at term: a population-based registry study among low-risk primiparous women.

To study the association between maternal age and emergency operative delivery. The roles of in‐labour indications, and birthweight ≥ 4000 g, gestational age ≥ 42 weeks, induction of labour, and epidural use, according to maternal age were explored.

Patterns of snus and cigarette use: a study of Norwegian men followed from age 16 to 19

Background The use of moist snuff (snus) in young Norwegians is increasing, while smoking rates are declining. It is not clear whether snus facilitates smoking. Objective To assess whether 16-year-old men who were never-smokers, but snus users in 2001, had an increased risk of smoking 3u2005years later. Methods In a prospective school-based cohort study, 1440 men, who responded to questionnaires in 2001 and 2004, were included in the analyses. The participation rate was 89% in 2001 and 50% in 2004. Multinomial logistic regression models were used to assess the OR of snus users, smokers and dual users of cigarettes and snus, compared with non-tobacco users at baseline, to be smokers at follow-up. Results Snus use at baseline was associated with increased odds of dual use at follow-up when the outcome was (1) current dual use versus no tobacco (OR 3.49, 95% CI 1.8 to 6.8) and when the outcome was (2) current dual use versus no smoking but including snus-only use (OR 1.88, 95% CI 1.1 to 3.3). Baseline snus users who were dual users at follow-up seemed to prefer using snus daily and cigarettes occasionally. Use of snus only at baseline was not associated with increased odds of smoking only at follow-up, after adjusting for known risk factors. Conclusions Young men who only used snus at baseline had an increased risk of being dual users at follow-up. Snus use may therefore facilitate smoking.

Elective cesarean section or not? Maternal age and risk of adverse outcomes at term: a population-based registry study of low-risk primiparous women

BackgroundMaternal age at delivery and cesarean section rates are increasing. In older women, the decision on delivery mode may be influenced by a reported increased risk of surgical interventions during labor and complications with increasing maternal age. We examined the association between maternal age and adverse outcomes in low-risk primiparous women, and the risk of adverse outcomes by delivery modes, both planned and performed (elective and emergency cesarean section, operative vaginal delivery, and unassisted vaginal delivery) in women agedu2009≥u200935xa0years.MethodsA population-based registry study was conducted using data from the Medical Birth Registry of Norway and Statistics Norway including 169,583 low-risk primiparas with singleton, cephalic labors atu2009≥u200937xa0weeks during 1999u2009−u20092009. Outcomes studied were obstetric blood loss, maternal transfer to intensive care units, 5-min Apgar score, and neonatal complications. We adjusted for potential confounders using relative risk models and multinomial logistic regression.ResultsMost adverse outcomes increased with increasing maternal age. However, the increase in absolute risks was low, except for moderate obstetric blood loss and transfer to the neonatal intensive care unit (NICU). Operative deliveries increased with increasing maternal age and in women agedu2009≥u200935xa0years, the risk of maternal complications in operative delivery increased. Neonatal adverse outcomes increased mainly in emergency operative deliveries. Moderate blood loss was three times more likely in elective and emergency cesarean section than in unassisted vaginal delivery, and twice as likely in operative vaginal delivery. Low Apgar score and neonatal complications occurred two to three times more often in emergency operative deliveries than in unassisted vaginal delivery. However, comparing outcomes after elective cesarean section and planned vaginal delivery, only moderate blood loss (higher in elective cesarean section), neonatal transfer to NICU and neonatal infections (both higher in planned vaginal delivery) differed significantly.ConclusionsMost studied adverse outcomes increased with increasing maternal age, as did operative delivery. Although emergency operative procedures were associated with an increased risk of adverse outcomes, the absolute risk difference in complications between the modes of delivery was low for the majority of outcomes studied.

Population data on calcium in drinking water and hip fracture: An association may depend on other minerals in water. A NOREPOS study.

BACKGROUNDnThe Norwegian population has among the highest hip fracture rates in the world. The incidence varies geographically, also within Norway. Calcium in drinking water has been found to be beneficially associated with bone health in some studies, but not in all. In most previous studies, other minerals in water have not been taken into account. Trace minerals, for which drinking water can be an important source and even fulfill the daily nutritional requirement, could act as effect-modifiers in the association between calcium and hip fracture risk. The aim of the present study was to investigate the association between calcium in drinking water and hip fracture, and whether other water minerals modified this association.nnnMATERIALS AND METHODSnA survey of trace metals in 429 waterworks, supplying 64% of the population in Norway, was linked geographically to the home addresses of patients with incident hip fractures (1994-2000). Drinking water mineral concentrations were divided into low (below and equal waterworks average) and high (above waterworks average). Poisson regression models were fitted, and all incidence rate ratios (IRRs) were adjusted for age, geographic region, urbanization degree, type of water source, and pH of the water. Effect modifications were examined by stratification, and interactions between calcium and magnesium, copper, zinc, iron and manganese were tested both on the multiplicative and the additive scale. Analyses were stratified on gender.nnnRESULTSnAmong those supplied from the 429 waterworks (2,110,916 person-years in men and 2,397,217 person-years in women), 5433 men and 13,493 women aged 50-85 years suffered a hip fracture during 1994-2000. Compared to low calcium in drinking water, a high level was associated with a 15% lower hip fracture risk in men (IRR=0.85, 95% CI: 0.78, 0.91) but no significant difference was found in women (IRR=0.98, 95%CI: 0.93-1.02). There was interaction between calcium and copper on hip fracture risk in men (p=0.051); the association between calcium and hip fracture risk was stronger when the copper concentration in water was high (IRR=0.52, 95% CI: 0.35, 0.78) as opposed to when it was low (IRR=0.88, 95% CI: 0.81, 0.94). This pattern persisted also after including potential confounding factors and other minerals in the model. No similar variation in risk was found in women.nnnCONCLUSIONnIn this large, prospective population study covering two thirds of the Norwegian population and comprising 19,000 hip fractures, we found an inverse association between calcium in drinking water and hip fracture risk in men. The association was stronger when the copper concentration in the water was high.

Does the Association of Comorbidity with 1-Year Mortality After Hip Fracture Differ According to Gender? The Norwegian Epidemiologic Osteoporosis Studies (NOREPOS)

Excess mortality after hip fracture is higher in men than in women. The objective was to study whether comorbidity differs in men and women with hip fracture and to what degree differences in comorbidity according to gender may explain the higher excess mortality in men.