Endometriosis and adverse maternal, fetal and neonatal outcomes, a systematic review and meta-analysis.

STUDY QUESTION: How is endometriosis associated with adverse maternal, fetal and neonatal outcomes of pregnancy? SUMMARY ANSWER: Women with endometriosis are at elevated risk for serious and important adverse maternal (pre-eclampsia, gestational diabetes, placenta praevia and Cesarean section) and fetal or neonatal outcomes (preterm birth, PPROM, small for gestational age, stillbirth and neonatal death). WHAT IS KNOWN ALREADY: A number of studies have shown an association between endometriosis and certain adverse maternal and fetal outcomes, but the results have been conflicting with potential for confounding by the use of assisted reproductive technology. STUDY DESIGN, SIZE, DURATION: A systematic review and meta-analysis of observational studies (1 January 1990-31 December 2017) that evaluated the effect of endometriosis on maternal, fetal and neonatal outcomes was conducted. PARTICIPANTS/MATERIALS, SETTING, METHODS: Studies were considered for inclusion if they were prospective or retrospective cohort or case-control studies; included women greater than 20 weeks gestational age with endometriosis; included a control group of gravid women without endometriosis; and, reported at least one of the outcomes of interest. Each study was reviewed for inclusion, data were extracted and risk of bias was assessed by two independent reviewers. MAIN RESULTS AND THE ROLE OF CHANCE: The search strategy identified 33 studies (sample size, n = 3 280 488) for inclusion. Compared with women without endometriosis, women with endometriosis had higher odds of pre-eclampsia (odds ratio [OR] = 1.18 [1.01-1.39]), gestational hypertension and/or pre-eclampsia (OR = 1.21 [1.05-1.39]), gestational diabetes (OR = 1.26 [1.03-1.55]), gestational cholestasis (OR = 4.87 [1.85-12.83]), placenta praevia (OR = 3.31 [2.37, 4.63]), antepartum hemorrhage (OR = 1.69 [1.38-2.07]), antepartum hospital admissions (OR = 3.18 [2.60-3.87]), malpresentation (OR = 1.71 [1.34, 2.18]), labor dystocia (OR = 1.45 [1.04-2.01]) and cesarean section (OR = 1.86 [1.51-2.29]). Fetuses and neonates of women with endometriosis were also more likely to have preterm premature rupture of membranes (OR = 2.33 [1.39-3.90]), preterm birth (OR = 1.70 [1.40-2.06]), small for gestational age <10th% (OR = 1.28 [1.11-1.49]), NICU admission (OR = 1.39 [1.08-1.78]), stillbirth (OR = 1.29 [1.10, 1.52]) and neonatal death (MOR = 1.78 [1.46-2.16]). Among the subgroup of women who conceived spontaneously, endometriosis was found to be associated with placenta praevia, cesarean section, preterm birth and low birth weight. Among the subgroup of women who conceived with the use of assisted reproductive technology, endometriosis was found to be associated with placenta praevia and preterm birth. LIMITATIONS, REASONS FOR CAUTION: As with any systematic review, the review is limited by the quality of the included studies. The diagnosis for endometriosis and the selection of comparison groups were not uniform across studies. However, the effect of potential misclassification would be bias towards the null hypothesis. WIDER IMPLICATIONS OF THE FINDINGS: The association between endometriosis with the important and serious pregnancy outcomes observed in our meta-analysis, in particular stillbirth and neonatal death, is concerning and warrants further studies to elucidate the mechanisms for the observed findings. STUDY FUNDING/COMPETING INTEREST(S): Dr Shifana Lalani is supported by a Physicians' Services Incorporated Foundation Research Grant, and Dr Innie Chen is supported by a University of Ottawa Clinical Research Chair in Reproductive Population Health and Health Services. Dr Singh declares conflicts of interests with Bayer, Abvie, Allergan and Cooper Surgical. All other authors have no conflicts of interests to declare. REGISTRATION NUMBER: PROSPERO CRD42015013911.

Maternal pre-gravid cardiometabolic health and infant birthweight: A prospective pre-conception cohort study.

BACKGROUND AND AIMS: Both low birthweight and high birthweight have been associated with the development of cardiometabolic disease in adulthood, possibly reflecting the effect of intrauterine fetal programming. As developmental programming can begin before conception, pre-gravid factors that predict birthweight may be relevant in this context. However, little is known about such factors. Thus, we established a pre-conception cohort to identify maternal pre-gravid cardiometabolic determinants of infant birthweight. METHODS AND RESULTS: In this prospective observational cohort study, 1484 newly-married women in Liuyang, China, underwent baseline (pre-gravid) evaluation and then were followed across a subsequent pregnancy. Pre-gravid cardiometabolic characterization consisted of clinical (anthropometry, blood pressure) and biochemical evaluation (total/LDL/HDL cholesterol, triglycerides, glucose) at median 20 weeks before a singleton pregnancy. Mean birthweight was 3294 ± 444 g, with 173 neonates large-for-gestational-age (LGA) and 110 small-for-gestational-age (SGA). On multiple linear regression analysis, positive determinants of birthweight were maternal age, pre-gravid body mass index (BMI), weight gain in pregnancy, length of gestation, and male infant (all p ≤ 0.0003). On logistic regression analysis, independent predictors of an LGA delivery were maternal age (OR = 1.10 per year, 95%CI 1.03-1.18), pre-gravid BMI (OR = 1.21 per kg/m2, 1.07-1.37), and gestational weight gain (OR = 1.10 per kg, 1.06-1.14). The only independent predictor of SGA was gestational weight gain (OR = 0.93 per kg, 0.89-0.97). CONCLUSION: Maternal weight before and during pregnancy is the predominant cardiometabolic determinant of infant birthweight, rather than pre-gravid blood pressure, glucose or lipid profile.

Maternal folate status and obesity/insulin resistance in the offspring: a systematic review.

OBJECTIVE: Prenatal folic acid supplementation or maternal folate sufficiency may protect the offspring from obesity and insulin resistance. This study aims to summarize the findings of association between prenatal folic acid supplementation/maternal folate sufficiency and obesity/insulin resistance in the offspring. METHODS: Twelve databases were searched for both published and unpublished work of prenatal folic acid supplementation/maternal folate status up to 1 July 2014. Experimental and observational studies on animals and human beings were included based on the eligibility criteria. There were no limits to the time period and language of publication. The study quality was assessed with a 10-Point Scale for Scientific Methodology. RESULTS: The search identified 2548 records. Nine animal studies and five human studies satisfied search criteria were included. Five of these nine animal studies showed a protective effect of folic acid. Of the five human studies, one showed a protective effect of folic acid, two showed a harmful effect and two showed uncertain results. CONCLUSIONS: Data from both animal studies and human studies are inconsistent. Future researches with sophisticated designs are needed to demonstrate the potential protective effect of maternal folate on obesity/insulin resistance in the offspring in animal models and human pregnancies.

A systematic review and network meta-analysis comparing the use of Foley catheters, misoprostol, and dinoprostone for cervical ripening in the induction of labour.

BACKGROUND: Various methods are used for cervical ripening during the induction of labour. It is still debatable which of these methods of treatment is optimal. OBJECTIVE: To compare treatment techniques for cervical ripening in the induction of labour. SEARCH STRATEGY: Medline, Embase, and the Cochrane Collaboration databases were searched using the keywords 'cervical ripening', 'labour induced', 'misoprostol', 'dinoprostone', and 'Foley catheter'. SELECTION CRITERIA: Randomised controlled trials (RCTs) of cervical ripening during the induction of labour, evaluating rates of failure to achieve vaginal delivery within 24 hours, incidence of uterine hyperstimulation with fetal heart rate (FHR) changes, and rates of caesarean section. Studies including women with prelabour rupture of membranes were excluded. DATA COLLECTION AND ANALYSIS: Outcome data were collected and analysed through pairwise meta-analysis and network meta-analysis within a Bayesian framework. MAIN RESULTS: A total of 96 RCTs (17,387 women) were included in the meta-analysis. Vaginal misoprostol was the most effective cervical ripening method to achieve vaginal delivery within 24 hours, but had the highest incidence of uterine hyperstimulation with FHR changes. The use of a Foley catheter to induce labour was associated with the lowest rate of uterine hyperstimulation accompanied by FHR changes. The caesarean section rate was lowest using oral misoprostol for the induction of labour. AUTHOR'S CONCLUSIONS: No method of labour induction demonstrated overall superiority when considering all three clinical outcomes. Decisions regarding the choice of induction method will depend upon the relative preference for effecting vaginal delivery within 24 hours, minimising the incidence of uterine hyperstimulation with adverse FHR changes and avoiding caesarean section. TWEETABLE ABSTRACT: Oral misoprostol for the induction of labour is safer than vaginal misoprostol and has the lowest rate of caesarean section.

The relationship between chitotriosidase activity and tuberculosis.

Chitotriosidase, secreted by activated macrophages, is a biomarker of activated macrophages. In this study, we explored whether chitotriosidase could be adopted as a biomarker to evaluate the curative effect on tuberculosis (TB). Five counties were randomly selected out of 122 counties/cities/districts in Hunan Province, China. Our cases were all TB patients who were newly diagnosed or had been receiving treatment at the Centers for Disease Control (CDCs) of these five counties between April and August in 2009. Healthy controls were selected from a community health facility in the Kaifu district of Changsha City after frequency-matching of gender and age with the cases. Chitotriosidase activity was evaluated by a fluorometric assay. Categorical variables were analysed with the χ 2 test. Measurement data in multiple groups were tested with analysis of variance and least significant difference (LSD). Correlation between chitotriosidase activity and the degree of radiological extent (DRE) was examined by Spearman's rank correlation test. The average chitotriosidase activity levels of new TB cases, TB cases with different periods of treatment (6 months) and the control group were 54·47, 34·77, 21·54, 12·73 and 10·53 nmol/h.ml, respectively. Chitotriosidase activity in TB patients declined along with the continuity of treatment. The chitotriosidase activity of both smear-positive and the smear-negative pulmonary TB patients decreased after 6 months' treatment to normal levels (P < 0·05). Moreover, chitotriosidase activity was positively correlated with DRE (r = 0·607, P < 0·001). Our results indicate that chitotriosidase might be a marker of TB treatment effects. However, further follow-up study of TB patients is needed in the future.

Characterization and effects of miR-21 expression in esophageal cancer.

The aim of this study was to investigate the expression of miR-21 in esophageal cancer and the impact of miR-21 on apoptosis, invasion, and the expression of target genes in esophageal cancer cells. Fluorescence quantitative polymerase chain reaction analysis was used to detect the expression of miR-21 in human esophageal tissues, adjacent tissues, and an esophageal cancer cell line (TE-13). The antisense miR-21 oligonucleotide was generated commercially using the solid-phase chemical synthesis method. Transient transfection was used to transfect esophageal cancer cells (TE-13 antisense and TE-13 control cells). Flow cytometry and Transwell cell assays were used to detect the apoptosis and invasion of esophageal cancer cells, respectively. The western blot method was used to detect the expression of PTEN, PDCD4, and K-ras proteins. These analyses determined that mir-21 expression significantly increased in esophageal cancer tissues and in TE-13 cells, and that this phenomenon was not associated with staging or lymph node metastasis. The apoptosis rate of TE-13 control cells was lower than that of antisense TE-13 cells indicating an enhanced invasive ability. In tissues adjacent to esophageal cancer and in TE-13 antisense cells, the expression of PTEN and PDCD4 was found to be higher than that in the control group, whereas the expression of K-ras showed the opposite pattern. Together, these results suggest that miR- 21 might be involved in the development and metastasis of esophageal cancer, through interaction with its PDCD4 and K-ras target genes.

Association of miR-21 with esophageal cancer prognosis: a meta-analysis.

The present study aimed to explore the relationship between miRNA expression and survival in patients with esophageal cancer (EC) using meta-analysis. We searched PubMed, EMBASE, CNKI, Wanfang, and ISI Web of Science databases without time restrictions, and extracted relevant data, such as the name of first author, publication year, age, gender, number of case, etc. from the studies included. We calculated the pooled hazard ratios (HRs) using the RevMan 5.2 software. A total of five studies involving 504 subjects were included in the meta-analysis, with the purpose of analyzing the association of miRNA-21 expression with EC prognosis. The pooled HR of elevated versus decreased miR-21 expression in EC was 1.87 [95% confidence interval (CI): 1.37-2.55, P < 0.001], with elevated miR-21 expression being associated with poorer prognosis for patients with EC. Our results support a prognostic role for miR-21 in EC.

Antiviral medication use in a cohort of pregnant women during the 2009-2010 influenza pandemic.

Preventing influenza-like illness (ILI) during pregnancy with antiviral medication use (AVMU) can mitigate serious health risks to mother and foetus. We report on AVMU in pregnant women in Ontario, Canada, and describe characteristics of AVMU during the 2009-2010 H1N1 pandemic. Rates and risk estimates of AVMU were compared across multiple categories and stratified across ILI infection status. Increased AVMU was observed in women with influenza infections, active smokers, those vaccinated against influenza, and those with pre-existing co-morbidities. Decreased AVMU was observed in women with multiple gestations, and those in neighbourhoods of high immigrant concentrations. Our stratified analysis indicated that the observed patterns differed by ILI infection status. We demonstrated that once infected, women across multiple groups were equally likely to use antiviral medications. In this report we also propose possible clinical explanations for the observed differences in AVMU, which will be useful in planning prevention initiatives for future pandemics.

Beta-blockers increase the risk of being born small for gestational age or of being institutionalised during infancy.

OBJECTIVE: To compare infant outcomes between mothers with hypertension treated by beta-blockers alone and by methyldopa alone during pregnancy. DESIGN: Historical cohort study. SETTING: Saskatchewan, Canada. POPULATION: Women who delivered a singleton birth in Saskatchewan during the periods from 1 January 1980 to 30 June 1987 or from 1 January 1990 to 31 December 2005 (women who delivered between 1 July 1987 and 31 December 1989 were excluded because the information recorded on maternal drug use during pregnancy is incomplete) with a diagnosis of a hypertensive disorder during pregnancy, and who were dispensed only beta-blockers (n = 416) or only methyldopa (n = 1000). METHODS: Occurrences of adverse infant outcomes were compared between women who received beta-blockers only and women who received methyldopa only during pregnancy, first in all eligible women, and then in women with chronic hypertension and in women with gestational hypertension or pre-eclampsia/eclampsia, separately. Multiple logistic regression analyses were performed to adjust for potential confounding. MAIN OUTCOME MEASURES: Small for gestational age (SGA) < 10th percentile, SGA < 3rd percentile, preterm birth, stillbirth, institutionalisation for respiratory distress syndrome (RDS), sepsis, seizure during infancy, and infant death. RESULTS: Adjusted odds ratios (aORs) and 95% confidence intervals (95% CIs) for infants born to mothers with chronic hypertension who were dispensed beta-blockers only, as compared with infants born to mothers who were dispensed methyldopa only, during pregnancy were: 1.95 (1.21-3.15), 2.17 (1.06-4.44), and 2.17 (1.09-4.34), respectively, for SGA < 10th percentile, SGA < 3rd percentile, and being institutionalised during infancy. CONCLUSIONS: For infants born to mothers with chronic hypertension, compared with those treated by methyldopa alone, those treated by beta-blockers appear to be at increased rates of SGA and hospitalisation during infancy.

Fetal macrosomia and adolescence obesity: results from a longitudinal cohort study.

OBJECTIVE: To assess the association between fetal macrosomia and adolescent obesity. DESIGN: Longitudinal cohort study of the association between macrosomia and adolescent obesity. SUBJECTS: Between 1 October 2005 and 1 February 2007, a follow-up study of live-born infants born in 1993-1995 in Wuxi, a suburban area of Shanghai, was conducted. Subjects with birth weight > 4000 g were selected as the exposed. For each exposed subject, one subject with a birth weight of 2500-4000 g, matched by year of birth, sex of infant, and type of institute at birth, was chosen as non-exposed. Clinical data were collected by structured interview and physical examination. Obesity was defined as body mass index (weight (kg)/height (m(2))) higher than the sex-age-specific criteria by the working group on obesity in China. Distribution of baseline characteristics and adolescent obesity rate between the exposed and non-exposed groups was compared. RESULTS: A total of 1435 pairs of exposed and non-exposed subjects were included in the final analysis. No major difference in baseline characteristics (other than birth weight) was found between the exposed and non-exposed groups. Obesity rate was significantly higher in the exposed group (2.9%) than in the non-exposed group (1.6%). Adolescent obesity rates were 1.4, 1.9, 2.6, and 5.6%, respectively, in study subjects with a birth weight of 2500-3499, 3500-3999, 4000-4499, and > or =4500 g. The association between birth weight and adolescent obesity remained essentially the same when mother's demographic and anthropometric factors, breast feeding, and adolescent life-style factors were adjusted. CONCLUSION: Compared with infants of normal birth weight, infants with birth weight >4000 g, especially those >4500 g, are at increased risk of adolescent obesity.

Comparison of maternal mortality between migrating population and permanent residents in Shanghai, China, 1996-2005.

OBJECTIVE: Maternal mortality ratio (MMR) in Shanghai residents has been declining in the past two decades and has reached levels comparable to developed countries. The MMR in migrating population in Shanghai remains high, however. The objectives of this study were to compare the trends of MMR between residents and migrating population in Shanghai from 1996 to 2005 and to explore the reasons for the dramatic differences in MMR between the two groups living in the same city. DESIGN: Retrospective cohort study. SETTING: Shanghai, China. POPULATION: A total of 902,807 pregnancies with live births in Shanghai in the period of 1996-2005. METHODS: We first compared the overall MMR between migrating population and permanent residents in Shanghai and examined temporal trends of MMR in the two subpopulations. We then compared the causes and maternal characteristics of maternal deaths between the two subpopulations. MAIN OUTCOME MEASURES: Maternal mortality and cause of death. RESULTS: A total of 902,807 live births and 243 maternal deaths were recorded in Shanghai in the period of 1996 to 2005, with an average MMR of 26.66 per 100,000 live births. The MMR in Shanghai residents declined dramatically from 22.47 per 100,000 in 1996 to 1.64 per 100,000 live births in 2005 (P < 0.01), while the MMR in migrating population was reduced only moderately from 54.68 per 100,000 live births to 48.46 per 100,000 (P > 0.05). The main causes of maternal deaths in migrating population were postpartum haemorrhage (39.9%), pregnancy-induced hypertension (9.8%), and puerperal infection (9.3%), whereas the main causes of maternal death of Shanghai residents were chronic heart and liver diseases (20.0%), postpartum haemorrhage (12.9%), and amniotic fluid embolism (12.9%). Among the maternal death cases in migrating women, 60% had elementary education or less, 22% were unemployed, 65% had no prenatal visit, 44% gave a birth at home, and 12% of the deaths occurred at home. CONCLUSION: Lack of access to quality maternity care, especially for the effective management of postpartum haemorrhage, is the main reason for the high MMR in migrating population in Shanghai.

Association between prophylactic low-molecular-weight heparin use in pregnancy and macrosomia: analysis of the Ottawa and Kingston birth cohort.

Essentials Low-molecular-weight heparin (LMWH) is used to prevent venous thromboembolism (VTE) in pregnancy. We evaluated the association between LMWH and large for gestational age (LGA) infants. We found no significant associations between LMWH use and LGA. LMWH does not appear to increase the risk for the delivery of an LGA infant. SUMMARY: Background Low-molecular-weight heparin (LMWH), an anticoagulant, is the recommended drug for thromboprophylaxis and treatment of venous thromboembolism (VTE) in pregnancy. During pregnancy, LMWH is routinely prescribed to mothers with an increased risk of VTE or with a history of thrombosis. Although clinical reports of larger offspring born to women administered LMWH have been noted, no studies to date have evaluated or associated the use of LMWH and large for gestational age (LGA) infants. Objectives To determine whether there is an association between LMWH usage in mothers and the prevalence of LGA. Patients/Methods We performed an analysis of the Ottawa and Kingston (OaK) Birth Cohort and report characteristics of LMWH and association LGA (> 10%ile). We used coarsened exact matching (CEM) methods to account for bias and confounding. Results A total of 7519 women from the OaK Birth Cohort were included; 59 were administered LMWH during pregnancy (0.78%). Mothers prescribed LMWH had significantly greater BMI (P = 0.0001), age (P = 0.0001) and parity (P = 0.02). Gestational length was shorter among women administered LMWH compared to those without treatment (37.7 ± 2.0 vs. 39.2 ± 2.0, P < 0.0001), an iatrogenic finding. The odds ratio of an LGA delivery among women administered LMWH was 1.02 (95% confidence interval [CI], 0.48-2.16; P = 0.96) in unadjusted analyses and was 1.15 (95% CI, 0.49-2.71) in the matched sample adjusted for maternal age, BMI and gestational age. Conclusions These results, although exploratory, provide indirect evidence of no increased risk of LGA infants among women prescribed LMWH.

Patterns of pregnancy exposure to prescription FDA C, D and X drugs in a Canadian population.

OBJECTIVE: To examine prescription Food and Drug Administration (FDA) C, D and X drugs in general obstetric population. STUDY DESIGN: Historical cohort study. RESULT: A total of 18 575 women who gave a birth in Saskatchewan between January 1997 and December 2000 were included. Among them, 3604 (19.4%) received FDA C, D or X drugs at least once during pregnancy. The pregnancy exposure rates were 15.8, 5.2 and 3.9%, respectively, for category C, D and X drugs, and were 11.2, 7.3 and 8.2%, respectively, in the first, second and third trimesters. Salbutamol (albuterol), trimethoprim/sulfamethoxazole (co-trimoxazole), ibuprofen, naproxen and oral contraceptives were the most common C, D, X drugs used during pregnancy. CONCLUSION: About one in every five women uses FDA C, D and X drugs at least once during pregnancy, and the most common prescription drugs in pregnancy are antiasthmatic, antibiotics, nonsteroid anti-inflammation drugs, antianxiety or antidepressants and oral contraceptives.

Hepatitis C infection and survivals of liver transplant patients in Canada, 1997-2003.

INTRODUCTION: Liver transplantation is an important health and health care issue for Canadians. Very few studies have estimated the survival results among liver transplant patients infected with hepatitis C virus (HCV) in Canada. METHODS: We carried out a retrospective cohort study to analyze 1- to 5-year survival rates among liver transplant patients, using Canadian Organ Replacement Registry data (1997-2003). Patients less than 19 years old were excluded from the study. The patients were categorized according to previous HCV infection status. The HCV-positive and HCV-negative groups were compared in the following characteristics: age group, gender, ethnicity, blood groups, donor type, pretransplantation medical status. Survival curves were plotted by Kaplan-Meier method. Stepwise regression model was applied to control the confounding impact related to gender, age, and HCV infection status. RESULTS: A total of 1842 liver transplant patients were included in the analysis. One-year survival rate for all patients was 85.4%. There were 319 HCV-positive recipients in the exposed group and 813 in the HCV-negative group. The HCV-positive and HCV-negative groups were comparable in age groups, ethnicity, ABO blood group, pretransplantation medical status, and donor organ type. The HCV-positive group had the higher male:female ratio (2.32:1) than the HCV-negative recipients (1.49:1) (Mantel Haenszel (MH) chi2 = 10.0311, P = .0015). There was no significant difference in 1-year survival rate between HCV-positive and HCV-negative groups, but the differences in the 2-year and 5-year survival rates were significant even after adjusting gender factor by stepwise regression analysis (MH chi2 = 4.4203, P = .0355). CONCLUSION: In Canada, the first-year survival rate is about 85.4%, which is comparable with other industrialized countries. The exaggerated survival disadvantage for HCV-positive recipients seems to be middle and long term, not short term.

Association of caesarean delivery for first birth with placenta praevia and placental abruption in second pregnancy.

OBJECTIVE: To quantify the risk of placenta praevia and placental abruption in singleton, second pregnancies after a caesarean delivery of the first pregnancy. DESIGN: Retrospective cohort study. SETTING: Linked birth and infant mortality database of the USA between 1995 and 2000. POPULATION: A total of 5,146,742 singleton second pregnancies were available for the final analysis after excluding missing information. METHODS: Multiple logistic regressions were used to describe the relationship between caesarean section at first birth and placenta praevia and placental abruption in second-birth singletons. MAIN OUTCOME MEASURES: Placenta praevia and placental abruption. RESULTS: Placenta praevia was recorded in 4.4 per 1000 second-birth singletons whose first births delivered by caesarean section and 2.7 per 1000 second-birth singletons whose first births delivered vaginally. About 6.8 per 1000 births were complicated with placental abruption in second-birth singletons whose first births delivered by caesarean section and 4.8 per 1000 birth in second-birth singletons whose first births delivered vaginally. The adjusted odds ratio (95% CIs) of previous caesarean section for placenta praevia in following second pregnancies was 1.47 (1.41, 1.52) after controlling for maternal age, race, education, marital status, maternal drinking and smoking during pregnancy, adequacy of prenatal care, and fetal gender. The corresponding figure for placental abruption was 1.40 (1.36, 1.45). CONCLUSION: Caesarean section for first live birth is associated with a 47% increased risk of placenta praevia and 40% increased risk of placental abruption in second pregnancy with a singleton.

Pregnancy-induced hypertension and infant mortality in triplets.

OBJECTIVE: To assess the effects of pregnancy-induced hypertension on infant mortality in triplets stratified by gestational age at birth. METHODS: A retrospective cohort study was conducted using the linked 1995-2000 US birth/infant death database. Generalized estimating equations were used to evaluate the observed association. RESULTS: Pregnancy-induced hypertension was associated with lesser neonatal mortality (odds ration [OR]: 0.34, 95% CI: 0.21, 0.54), postneonatal mortality (OR: 0.54, 95% CI: 0.30, 0.99) and infant mortality (OR, 0.37, 95% CI: 0.25, 0.55) in triplets. It was also associated with a decreased risk of neonatal death (OR, 0.38; 95% CI, 0.21-0.67), postneonatal death (OR, 0.45; 95% CI, 0.21-0.97), and infant death (OR, 0.39; 95% CI, 0.24-0.64) in early preterm triplets, whereas the association was not significant in late preterm or in full-term triplets. CONCLUSION: Pregnancy-induced hypertension is associated with a decreased risk of infant mortality in triplets. This effect varies with gestational age at birth.

Initiation and growth kinetics of solidification cracking during welding of steel.

Solidification cracking is a key phenomenon associated with defect formation during welding. To elucidate the failure mechanisms, solidification cracking during arc welding of steel are investigated in situ with high-speed, high-energy synchrotron X-ray radiography. Damage initiates at relatively low true strain of about 3.1% in the form of micro-cavities at the weld subsurface where peak volumetric strain and triaxiality are localised. The initial micro-cavities, with sizes from 10 × 10-6 m to 27 × 10-6 m, are mostly formed in isolation as revealed by synchrotron X-ray micro-tomography. The growth of micro-cavities is driven by increasing strain induced to the solidifying steel. Cavities grow through coalescence of micro-cavities to form micro-cracks first and then through the propagation of micro-cracks. Cracks propagate from the core of the weld towards the free surface along the solidifying grain boundaries at a speed of 2-3 × 10-3 m s-1.

Neonatal mortality and morbidity in vertex-vertex second twins according to mode of delivery and birth weight.

OBJECTIVE: To assess the risk of neonatal mortality and morbidity in vertex-vertex second twins according to mode of delivery and birth weight. STUDY DESIGN: Data from a historical cohort study based on a twin registry in the US (1995-1997) were used. Multivariate logistic regression was used to control for maternal age, race, marital status, cigarette smoking during pregnancy, parity, medical complications, gestational age, and other confounders. RESULTS: A total of 86 041 vertex-vertex second twins were classified into two groups: second twins delivered by cesarean section after cesarean delivery of first twin (C-C) (43.0%), second twins whose co-twins delivered vaginally (V-X) (57.0%). In infants of birth weight>or=2500 g group, the risks of noncongenital anomaly-related death (adjusted odds ratio (aOR): 4.64, 95% confidence interval (95% CI): 1.90, 13.92), low Apgar score (aOR: 2.39, 95% CI: 1.43, 4.14), and ventilation use (aOR: 1.31, 95% CI: 1.18, 1.47) were higher in the V-X group compared with the C-C group. No asphyxia-related neonatal deaths occurred in C-C group, whereas the incidence of this death was 0.04% in the V-X group. CONCLUSION: The risks of neonatal mortality and morbidity are increased in vertex-vertex second twins with birth weight>or=2500 g whose co-twins delivered vaginally compared with second twins delivered by cesarean section after cesarean delivery of first twin.

Survival analysis of liver transplant patients in Canada 1997-2002.

UNLABELLED: Liver transplantation is an important health care issue for Canadians. Very few studies have assessed survival and determinants of survival in liver transplant patients in Canada. METHODS: We carried out an epidemiological analysis of 1 year survival and determinants of 1 year survival in liver transplant patients, using Canadian Organ Replacement Registry data (1997-2002). Survival curves were plotted by the Kaplan-Meier method. Cox proportional hazards analysis was applied to evaluate hazard ratios with different age groups, gender, ethnicity, blood groups, donor type, pretransplantation medical status, and HBV infection status. RESULTS: A total of 1164 liver transplant patients were included in the analysis. One-year survival rate was 84.7%. Male recipients had a 21% higher risk of developing organ failure than females. Recipients over 60 years of age had a 5% lower survival probability in comparison with recipients below 20 years of age. Pacific Islanders and Aboriginals had 32% and 9% lower survival probabilities, respectively, in comparison with Caucasians. Type B blood recipients had a 12% higher survival probability, whereas type AB blood recipients had a 7% lower survival probability compared with type O blood recipients. Twenty-six live organ recipients had 40% higher survival probabilities than 1138 cadaveric organ recipients. Patients with fulminant hepatitis (status 3F) had the highest survival, while patients with fulminant failure in ICU with intubation/ventilation (status 4F) had the lowest survival. One hundred sixty-seven recipients with positive HBsAg antigen showed 10% lower survival probability than 997 cases with negative HBsAg antigen. CONCLUSION: In Canada, the first year survival rate is about 85%, which is comparable with other industrialized countries. Type of donor organs and recipient gender, ethnicity, ABO blood group, pretransplantation medical status, and HBV infection status had significant affects on the recipient survival.