701 research outputs found
Impact of Caesarean section on subsequent fertility: a systematic review and meta-analysis.
STUDY QUESTION: Is there an association between a Caesarean section and subsequent fertility? SUMMARY ANSWER: Most studies report that fertility is reduced after Caesarean section compared with vaginal delivery. However, studies with a more robust design show smaller effects and it is uncertain whether the association is causal. WHAT IS KNOWN ALREADY: A previous systematic review published in 1996 summarizing six studies including 85 728 women suggested that Caesarean section reduces subsequent fertility. The included studies suffer from severe methodological limitations. STUDY DESIGN, SIZE, DURATION: Systematic review and meta-analysis of cohort studies comparing subsequent reproductive outcomes of women who had a Caesarean section with those who delivered vaginally. PARTICIPANTS/MATERIALS, SETTING, METHODS: Searches of Cochrane Library, Medline, Embase, CINAHL Plus and Maternity and Infant Care databases were conducted in December 2011 to identify randomized and non-randomized studies that compared the subsequent fertility outcomes after a Caesarean section and after a vaginal delivery. Eighteen cohort studies including 591 850 women matched the inclusion criteria. Risk of bias was assessed by the Newcastle-Ottawa scale (NOS). Data extraction was done independently by two reviewers. The meta-analysis was based on a random-effects model. Subgroup analyses were performed to assess whether the estimated effect was influenced by parity, risk adjustment, maternal choice, cohort period, and study quality and size. MAIN RESULTS AND THE ROLE OF CHANCE: The impact of Caesarean section on subsequent pregnancies could be analysed in 10 studies and on subsequent births in 16 studies. A meta-analysis suggests that patients who had undergone a Caesarean section had a 9% lower subsequent pregnancy rate [risk ratio (RR) 0.91, 95% confidence interval (CI) (0.87, 0.95)] and 11% lower birth rate [RR 0.89, 95% CI (0.87, 0.92)], compared with patients who had delivered vaginally. Studies that controlled for maternal age or specifically analysed primary elective Caesarean section for breech delivery, and those that were least prone to bias according to the NOS reported smaller effects. LIMITATIONS, REASONS FOR CAUTION: There is significant variation in the design and methods of included studies. Residual bias in the adjusted results is likely as no study was able to control for a number of important maternal characteristics, such as a history of infertility or maternal obesity. WIDER IMPLICATIONS OF THE FINDINGS: Further research is needed to reduce the impact of selection bias by indication through creating more comparable patient groups and applying risk adjustment
National Vascular Registry: 2014 Progress Report.
The National Vascular Registry is commissioned by the Healthcare Quality Improvement
Partnership (HQIP) to measure the quality and outcomes of care for patients who undergo
major vascular surgery in NHS hospitals in England and Wales. It aims to provide
comparative information on the performance of NHS hospitals and thereby support local
quality improvement as well as inform patients about the care delivered in the NHS. As
such, all NHS hospitals in England, Wales, Scotland and Northern Ireland are encouraged to
participate in the Registry.
The measures used to describe the patterns and outcomes of care are drawn from various
national guidelines including: the “2014 The Provision of Services for Patients with Vascular
Disease” and the Quality Improvement Frameworks published by the Vascular Society, and
the National Institute for Health and Care Excellence (NICE) guidelines on stroke and
peripheral arterial disease.
In 2014, the Registry published NHS trust and surgeon-level information for elective infrarenal
Abdominal Aortic Aneurysm (AAA) repair and carotid endarterectomy on the Registry
website. From 28 October, information on both procedures has been available on the
www.vsqip.org.uk website for all UK NHS trusts that currently perform them. For English
NHS trusts, the same information was published for individual consultants, as part of NHS
England’s “Everyone Counts: Planning for Patients 2013/4” initiative. Consultant-level
information was also published for NHS hospitals in Wales, Scotland and Northern Ireland
for consenting surgeons.
This progress report aims to complement that information by (1) providing an overview of
care delivered by the NHS at a national level, and (2) describing various developments
within the National Vascular Registry. The Registry will publish its next annual report on
major vascular surgery in November 2015
National Vascular Registry: 2015 Annual Report.
The National Vascular Registry is commissioned by the Healthcare Quality Improvement
Partnership (HQIP) to measure the quality and outcomes of care for patients who undergo
major vascular surgery in NHS hospitals in England and Wales. It aims to provide
comparative information on the performance of NHS vascular units and thereby support
local quality improvement as well as inform patients about major vascular interventions
delivered in the NHS. As such, all NHS hospitals in England, Wales, Scotland and Northern
Ireland are encouraged to participate in the Registry.
The measures used to describe the patterns and outcomes of care are drawn from various
national guidelines including: the “Provision of Services for Patients with Vascular Disease”
document and the Quality Improvement Frameworks published by the Vascular Society, and
the National Institute for Health and Care Excellence (NICE) guidelines on stroke and
peripheral arterial disease.
This report provides a description of the care provided by NHS vascular units, and contains
information on the process and outcomes of care for: (i) patients undergoing abdominal
aortic aneurysm (AAA) repair, (ii) patients undergoing carotid endarterectomy, (iii) patients
undergoing a revascularisation procedure (angioplasty/stent or bypass) or major
amputation for lower-limb peripheral arterial disease (PAD). In addition, the report
presents the findings of an organisational audit conducted in August 2015
A population-based cohort study of the effect of Caesarean section on subsequent fertility
STUDY QUESTION Is there an association between Caesarean section and subsequent fertility?
SUMMARY ANSWER There is no or only a slight effect of Caesarean section on future fertility.
WHAT IS KNOWN ALREADY Previous studies have reported that delivery by a Caesarean section is associated with fewer subsequent pregnancies and longer inter-pregnancy intervals. The interpretation of these findings is difficult because of significant weaknesses in study designs and analytical methods, notably the potential effect of the indication for Caesarean section on subsequent delivery.
STUDY DESIGN, SIZE, DURATION Retrospective cohort study of 1 047 644 first births to low-risk women using routinely collected, national administrative data of deliveries in English maternity units between 1 April 2000 and 31 March 2012.
PARTICIPANTS/MATERIALS, SETTING, METHODS Primiparous women aged 15–40 years who had a singleton, term, live birth in the English National Health Service were included. Women with high-risk pregnancies involving placenta praevia, pre-eclampsia, eclampsia (gestational or pre-existing), hypertension or diabetes were excluded from the main analysis. Kaplan–Meier analyses and Cox proportional hazard models were used to assess the effect of mode of delivery on time to subsequent birth, adjusted for age, ethnicity, socio-economic deprivation and year of index delivery.
MAIN RESULTS AND THE ROLE OF CHANCE Among low-risk primiparous women, 224 024 (21.4%) were delivered by Caesarean section. The Kaplan–Meier estimate of the subsequent birth rate at 10 years for the cohort was 74.7%. Compared with vaginal delivery, subsequent birth rates were marginally lower after elective Caesarean for breech (adjusted hazard ratio, HR 0.96, 95% CI 0.94–0.98). Larger effects were observed after elective Caesarean for other indications (adjusted HR 0.81, 95% CI 0.78–0.83), and emergency Caesarean (adjusted HR 0.91, 95% CI 0.90–0.93). The effect was smallest for elective Caesarean for breech, and this was not statistically significant in women younger than 30 years of age (adjusted HR 0.98, 95% CI 0.96–1.01).
LIMITATIONS, REASONS FOR CAUTION We used birth cohorts from maternity units with good quality parity information. The data are likely to be nationally representative because the characteristics of the deliveries in included and omitted units were similar. There may be residual bias in our adjusted results due to unmeasured maternal factors such as obesity and voluntary absence of conception. Any residual bias would lead to an overestimate of the effect of Caesarean section on fertility, and the true effect is therefore likely to be smaller than the effect reported in our study.
WIDER IMPLICATIONS OF THE FINDINGS Our results provide strong evidence that there is no or only a slight effect of Caesarean section on future fertility. The clinical and social circumstances leading to the Caesarean section have a greater effect on future fertility than the Caesarean section itself. This finding is important in light of rising Caesarean section rates.
STUDY FUNDING/COMPETING INTEREST(S) IG-U is supported by the Lindsay Stewart R&D Centre, Royal College of Obstetricians and Gynaecologists, UK. The authors have no conflicts of interest to declare.
TRIAL REGISTRATION NUMBER n/a
Elastic energy of polyhedral bilayer vesicles
In recent experiments [M. Dubois, B. Dem\'e, T. Gulik-Krzywicki, J.-C.
Dedieu, C. Vautrin, S. D\'esert, E. Perez, and T. Zemb, Nature (London) Vol.
411, 672 (2001)] the spontaneous formation of hollow bilayer vesicles with
polyhedral symmetry has been observed. On the basis of the experimental
phenomenology it was suggested [M. Dubois, V. Lizunov, A. Meister, T.
Gulik-Krzywicki, J. M. Verbavatz, E. Perez, J. Zimmerberg, and T. Zemb, Proc.
Natl. Acad. Sci. U.S.A. Vol. 101, 15082 (2004)] that the mechanism for the
formation of bilayer polyhedra is minimization of elastic bending energy.
Motivated by these experiments, we study the elastic bending energy of
polyhedral bilayer vesicles. In agreement with experiments, and provided that
excess amphiphiles exhibiting spontaneous curvature are present in sufficient
quantity, we find that polyhedral bilayer vesicles can indeed be energetically
favorable compared to spherical bilayer vesicles. Consistent with experimental
observations we also find that the bending energy associated with the vertices
of bilayer polyhedra can be locally reduced through the formation of pores.
However, the stabilization of polyhedral bilayer vesicles over spherical
bilayer vesicles relies crucially on molecular segregation of excess
amphiphiles along the ridges rather than the vertices of bilayer polyhedra.
Furthermore, our analysis implies that, contrary to what has been suggested on
the basis of experiments, the icosahedron does not minimize elastic bending
energy among arbitrary polyhedral shapes and sizes. Instead, we find that, for
large polyhedron sizes, the snub dodecahedron and the snub cube both have lower
total bending energies than the icosahedron
Patient experience of the process to diagnosis of chronic limb‐threatening ischaemia: a qualitative study
Introduction
Delays exist at each stage of the chronic limb-threatening ischaemia (CLTI) care pathway, but there is little known about patient factors influencing delay to diagnosis of CLTI. This study explores the experiences and perceptions of patients recently diagnosed with CLTI.
Methods
A qualitative interview study was conducted. Sixteen participants underwent semi-structured interviews. Reflexive thematic analysis was performed on the data, aiming to understand factors which can influence delay in the CLTI care pathway.
Results
Five interrelated themes were developed: CLTI is a devastating condition; Reluctance to ask for help; When we are empowered we get better care; Luck plays a role in the process to diagnosis; and Vascular units can do better, comprising sub-themes of information transfer—consider communication and arterial versus non-arterial centres—proximity isn't everything.
Conclusions
The five themes generated from the interview data describe factors relevant to delay given meaning by participants who have lived experience of CLTI. Theme content should be noted by clinicians, commissioners and providers looking to improve care pathways for patients with CLTI. The importance of awareness for the public, patients and clinicians linked ideas in some themes and interventions to raise awareness should be considered
Characterization of Knots and Links Arising From Site-specific Recombination on Twist Knots
We develop a model characterizing all possible knots and links arising from
recombination starting with a twist knot substrate, extending previous work of
Buck and Flapan. We show that all knot or link products fall into three
well-understood families of knots and links, and prove that given a positive
integer , the number of product knots and links with minimal crossing number
equal to grows proportionally to . In the (common) case of twist knot
substrates whose products have minimal crossing number one more than the
substrate, we prove that the types of products are tightly prescribed. Finally,
we give two simple examples to illustrate how this model can help determine
previously uncharacterized experimental data.Comment: 32 pages, 7 tables, 27 figures, revised: figures re-arranged, and
minor corrections. To appear in Journal of Physics
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Effectiveness of a quality improvement collaborative in reducing time to surgery for patients requiring emergency cholecystectomy.
Background:Acute gallstone disease is a high-volume emergency general surgery presentation with wide variations in the quality of care provided across the UK. This controlled cohort evaluation assessed whether participation in a quality improvement collaborative approach reduced time to surgery for patients with acute gallstone disease to fewer than 8 days from presentation, in line with national guidance. Methods:Patients admitted to hospital with acute biliary conditions in England and Wales between 1 April 2014 and 31 December 2017 were identified from Hospital Episode Statistics data. Time series of quarterly activity were produced for the Cholecystectomy Quality Improvement Collaborative (Chole-QuIC) and all other acute National Health Service hospitals (control group). A negative binomial regression model was used to compare the proportion of patients having surgery within 8 days in the baseline and intervention periods. Results:Of 13 sites invited to join Chole-QuIC, 12 participated throughout the collaborative, which ran from October 2016 to January 2018. Of 7944 admissions, 1160 patients had a cholecystectomy within 8 days of admission, a significant improvement (P < 0·050) from baseline performance. This represented a relative change of 1·56 (95 per cent c.i. 1·38 to 1·75), compared with 1·08 for the control group. At the individual site level, eight of the 12 Chole-QuIC sites showed a significant improvement (P < 0·050), with four sites increasing their 8-day surgery rate to over 20 per cent of all emergency admissions, well above the mean of 15·3 per cent for control hospitals. Conclusion:A surgeon-led quality improvement collaborative approach improved care for patients requiring emergency cholecystectomy
Bringing research alive through stories: reflecting on research storytelling as a public engagement method
Stories are vital in making sense of our lives – and research. Consequently, 12 researchers from the University of Sheffield underwent a three-month training process from September to November 2019 to learn how to shape their research experiences into accessible, ten-minute, spoken stories. This culminated in a storytelling evening as part of the Economic and Social Research Council’s Festival of Social Science, at which researchers from different disciplines discussed various nature–society dynamics in diverse field sites in the Global South. By reflecting on the training process and the performance through qualitative interviews with storytellers and audience members, our study answers the research question: What lessons emerge from an interdisciplinary group of researchers engaging with research storytelling for public engagement? Our study addresses gaps in the literature by focusing on interdisciplinary research storytelling, spoken ten-minute stories, bringing together storytellers’ and audience’s viewpoints, and providing practical recommendations for researchers and practitioners. We argue that research storytelling can have diverse benefits for both researchers and listeners by promoting learning in an accessible format, boosting self-confidence and helping (un/re)learn scholarly communication. However, professional guidance and peer support, as well as ethical sensitivity, are crucial
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