Please cite this paper as: McCowan L, Roberts C, Dekker G, Taylor R, Chan E, Kenny L, Baker P, Moss‐Morris R, Chappell L, North R on behalf of the SCOPE consortium. Risk factors for ...small‐for‐gestational‐age infants by customised birthweight centiles: data from an international prospective cohort study. BJOG 2010;117:1599–1607.
Objective To identify clinical and ultrasound variables associated with the birth of small‐for‐gestational‐age (SGA) infants by customised centiles, subclassified according to whether their mothers were normotensive or developed hypertensive complications.
Design Prospective, multicentre cohort study.
Setting Participating centres of the Screening for Pregnancy Endpoints (SCOPE) study in Auckland, New Zealand, Adelaide, Australia, Manchester and London, UK, and Cork, Ireland.
Population The 3513 nulliparous participants of the SCOPE study.
Methods Women were interviewed at 15 ± 1 weeks, and had ultrasound growth measurements and umbilical and uterine Doppler studies at 20 ± 1 weeks. Variables associated with SGA infants were identifed using logistic regression.
Main outcome measures Small for gestational age (i.e. a birthweight of less than the tenth customised centile), normotensive‐SGA and hypertensive‐SGA. Comparison groups for statistical analyses were non‐SGA, normotensive non‐SGA and hypertensive non‐SGA.
Results Among 376 (10.7%) SGA infants, 281 (74.7%) were normotensive‐SGA and 95 (25.3%) were hypertensive‐SGA. Independent risk factors for normotensive‐SGA were low maternal birthweight, low fruit intake pre‐pregnancy, cigarette smoking, increasing maternal age, daily vigorous exercise, being a tertiary student, head and abdominal circumference of less than the tenth centile and increasing uterine artery Doppler indices at the 20‐week scan. Protective factors were: high green leafy vegetable intake pre‐pregnancy, and rhesus‐negative blood group. Risk factors for hypertensive‐SGA were conception by in vitro fertilisation, previous early pregnancy loss and femur length of less than tenth centile at the 20‐week scan.
Conclusions Risk factors for infants who are SGA by customised centiles have been identified in a cohort of healthy nulliparous women. A number of these factors are modifiable; however, further studies are needed to replicate these findings.
Objective
To establish a gestation‐specific reference range for D‐dimer in healthy pregnant women with a singleton pregnancy using the Auto‐Dimer assay.
Design
Cross‐sectional study
Setting
Cork ...University Maternity Hospital, Ireland.
Population
Healthy pregnant women attending for routine antenatal care.
Methods
Simultaneous‐quantile regression was performed to construct a median, 5th percentile, and 95th percentile, model of normal pregnancy D‐dimer concentration versus gestational week, ranging from week 6 to 42. Additionally, pair‐wise Mann–Whitney U‐tests were performed to compare distributions of D‐dimer concentrations for each of the four discrete gestational sampling windows with the distribution of D‐dimer concentrations 48 hours postpartum.
Main outcome measures
D‐dimer concentrations (ng/ml) during normal gestation (approximately week 6 to week 42).
Results
Seven hundred and sixty healthy pregnant women were investigated between gestational age week 5 and 48 hours postpartum. There was a clear steady increase in median D‐dimer concentrations over the complete gestational period. Additionally, the 95th centile estimates for all gestational time‐points were above the accepted non‐pregnancy normal cut‐off concentration (224 ng/ml). The results of the Mann–Whitney U‐tests suggested that the long‐term postnatal return to normal D‐dimer concentrations begins in the immediate postpartum period.
Conclusions
We found that there is a continuous increase in D‐dimer concentrations across all gestations. This research is potentially beneficial to future diagnosis of venous thromboembolism (VTE) in pregnancy using the new recommended 95th centile potential cut‐offs. Possible further investigation involves an observational study comparing D‐dimer concentrations in women with proven DVT with those that don't, generating likelihood ratios.
Obesity during pregnancy is associated with increased risk of gestational diabetes mellitus (GDM) and other complications. Physical activity is a modifiable lifestyle factor that may help to prevent ...these complications but many women reduce their physical activity levels during pregnancy. Interventions targeting physical activity in pregnancy are on-going but few identify the underlying behaviour change mechanisms by which the intervention is expected to work. To enhance intervention effectiveness, recent tools in behavioural science such as the Theoretical Domains Framework (TDF) and COM-B model (capability, opportunity, motivation and behaviour) have been employed to understand behaviours for intervention development. Using these behaviour change methods, this study aimed to identify the enablers and barriers to physical activity in overweight and obese pregnant women.
Semi-structured interviews were conducted with a purposive sample of overweight and obese women at different stages of pregnancy attending a public antenatal clinic in a large academic maternity hospital in Cork, Ireland. Interviews were recorded and transcribed into NVivo V.10 software. Data analysis followed the framework approach, drawing on the TDF and the COM-B model.
Twenty one themes were identified and these mapped directly on to the COM-B model of behaviour change and ten of the TDF domains. Having the social opportunity to engage in physical activity was identified as an enabler; pregnant women suggested being active was easier when supported by their partners. Knowledge was a commonly reported barrier with women lacking information on safe activities during pregnancy and describing the information received from their midwife as 'limited'. Having the physical capability and physical opportunity to carry out physical activity were also identified as barriers; experiencing pain, a lack of time, having other children, and working prevented women from being active.
A wide range of barriers and enablers were identified which influenced women's capability, motivation and opportunity to engage in physical activity with "knowledge" as the most commonly reported barrier. This study is a theoretical starting point in making a 'behavioural diagnoses' and the results will be used to inform the development of an intervention to increase physical activity levels among overweight and obese pregnant women.
Abstract Preeclampsia remains a leading cause of maternal and fetal morbidity and mortality and has an unknown etiology. The limited progress made regarding new treatments to reduce the incidence and ...severity of preeclampsia has been attributed to the difficulties faced in the development of suitable animal models for the mechanistic research of this disease. In addition, animal models need hypotheses on which to be based and the slow development of testable hypotheses has also contributed to this poor progress. The past decade has seen significant advances in our understanding of preeclampsia and the development of viable reproducible animal models has contributed significantly to these advances. Although many of these models have features of preeclampsia, they are still poor overall models of the human disease and limited due to lack of reproducibility and because they do not include the complete spectrum of pathophysiological changes associated with preeclampsia. This review aims to provide a succinct and comprehensive assessment of current animal models of preeclampsia, their uses and limitations with particular attention paid to the best validated and most comprehensive models, in addition to those models which have been utilized to investigate potential therapeutic interventions for the treatment or prevention of preeclampsia.
Objective
To determine: (1) the association between metabolic syndrome (MetS), time to pregnancy (TTP), and infertility; (2) associations between individual and an increasing number of MetS ...components, TTP, and infertility; and (3) whether these relationships differ by body mass index (BMI < 30 kg/m2 versus BMI ≥ 30 kg/m2).
Design
Retrospective cohort study.
Setting
Multiple centres (in Australia, Ireland, New Zealand, and the UK).
Population
Five thousand five hundred and nineteen low‐risk nulliparous pregnant women.
Methods
Data on retrospectively reported TTP (number of months to conceive) and a blood sample to assess metabolic health were collected between 14 and 16 weeks of gestation. MetS was defined according to the International Diabetes Federation criteria. Accelerated failure time models with log‐normal distribution were conducted to estimate time ratios (TRs) and 95% CIs. Differences in MetS on infertility (TTP > 12 months) were compared using a generalised linear model (Poisson distribution) with robust variance estimates (relative risks, RRs; 95% CIs). All analyses (entire cohort and split by BMI) were controlled for a range of maternal and paternal confounding factors.
Main outcome measures
Time to pregnancy and infertility.
Results
Of the 5519 women included, 12.4% (n = 684) had MetS. Compared with women without MetS, women with MetS had a longer TTP (adjusted TR 1.30; 95% CI 1.15–1.46), which was similar in women who were obese and in women who were not obese. Marginal estimates for median TTP in women with MetS versus without MetS was 3.1 months (3.0–3.3 months) versus 4.1 months (3.6–4.5 months), respectively. Women with MetS were at a 62% greater risk for infertility and were at a greater risk for infertility whether they were obese (adjusted RR 1.62; 95% CI 1.15–2.29) or not (adjusted RR 1.73; 95% CI 1.33–2.23). Reduced high‐density lipoprotein cholesterol (HDL‐C) and raised triglycerides (TGs) were the main individual components associated with risk for infertility.
Conclusion
Metabolic syndrome is associated with longer TTP and infertility, independent of obesity. Additional studies, before pregnancy, are required to support our findings and to determine the applicability of which combinations of metabolic abnormalities pose the greatest risk to delayed fertility, or whether individual components are amenable to modification.
Tweetable
Metabolic syndrome is associated with longer time to pregnancy and infertility, independent of obesity.
Tweetable
Metabolic syndrome is associated with longer time to pregnancy and infertility, independent of obesity.
The increasing prevalence of obesity is presenting a critical challenge to healthcare services. We examined the effect of Body Mass Index in early pregnancy on adverse pregnancy outcome. We performed ...a population register-based cohort study using data from the North Western Perinatal survey (N = 99,403 babies born during 2004-2006), based at The University of Manchester, UK. The main outcome measures were Caesarean section delivery, preterm birth, neonatal death, stillbirth, Macrosomia, small for gestational age and large for gestational age. The risk of preterm birth was reduced by almost 10% in overweight (RR = 0.89, 95% CI: 0.83, 0.95) and obese women (RR = 0.90, 95% CI: 0.84, 0.97) and was increased in underweight women (RR = 1.33, 95% CI: 1.16, 1.53). Overweight (RR = 1.17, 95% CI: 1.09, 1.25), obese (RR = 1.35, 95% CI: 1.25, 1.45) and morbidly obese (RR = 1.24, 95% CI: 1.02, 1.52) women had an elevated risk of post-term birth compared to normal women. The risk of fetal macrosomia and operative delivery increased with BMI such that morbidly obese women were at greatest risk of both (RR of macrosomia = 4.78 95% CI: 3.86, 5.92 and RR of Caesarean section = 1.66 95% CI: 1.61, 1.71 and a RR of emergency Caesarean section = 1.59 95% CI: 1.45, 1.75). Excessive leanness and obesity are associated with different adverse pregnancy outcomes with major maternal and fetal complications. Overweight and obese women have a higher risk of macrosomia and Caesarean delivery and lower risk of preterm delivery. The mechanism underlying this association is unclear and is worthy of further investigation.
3D printing is a manufacturing process that is usually used for modeling and prototyping. One of the most popular printing techniques is fused deposition modeling (FDM), which is based on adding ...melted material layer by layer. Although FDM has several advantages with respect to other manufacturing materials, there are several problems that have to be faced. When setting the printing options, several parameters have to be taken into account, such as temperature, speed, infill percentage, etc. Selecting these parameters is often a great challenge for the user, and is generally solved by experience without considering the influence of variations in the parameters on the mechanical properties of the printed parts.This article analyzes the influence of the infill percentage on the mechanical properties of ABS (Acrylonitrile Butadiene Styrene) printed parts. In order to characterize this influence, test specimens for tensile strength and Charpy tests were printed with a Makerbot Replicator 2X printer, in which the infill percentage was varied but the rest of the printing parameters were kept constant. Three different results were analyzed for these tests: tensile strength, impact resistance, and effective printing time. Results showed that the maximum tensile force (1438N) and tensile stress (34,57MPa) were obtained by using 100% infill. The maximum impact resistance, 1,55J, was also obtained with 100% infill. In terms of effective printing time, results showed that printing with an infill range between 50% and 98% is not recommended, since the effective printing time is higher than with a 100% infill and the tensile strength and impact resistance are smaller. In addition, in comparing the results of our analysis with results from other authors, it can be concluded that the printer type and plastic roll significantly influence the mechanical properties of ABS parts.
Objectives
To assess the performance of clinical risk factors, uterine artery Doppler and angiogenic markers to predict preterm pre‐eclampsia in nulliparous women.
Design
Predictive test accuracy ...study.
Setting
Prospective multicentre cohort study Screening for Pregnancy Endpoints (SCOPE).
Methods
Low‐risk nulliparous women with a singleton pregnancy were recruited. Clinical risk factor data were obtained and plasma placental growth factor (PlGF), soluble endoglin and soluble fms‐like tyrosine kinase‐1 (sFlt‐1) were measured at 14–16 weeks of gestation. Prediction models were developed using multivariable stepwise logistic regression.
Main outcome measure
Preterm pre‐eclampsia (delivered before 37+0 weeks of gestation).
Results
Of the 3529 women recruited, 187 (5.3%) developed pre‐eclampsia of whom 47 (1.3%) delivered preterm. Controls (n = 188) were randomly selected from women without preterm pre‐eclampsia and included women who developed other pregnancy complications. An area under a receiver operating characteristic curve (AUC) of 0.76 (95% CI 0.67–0.84) was observed using previously reported clinical risk variables. The AUC improved following the addition of PlGF measured at 14–16 weeks (0.84; 95% CI 0.77–0.91), but no further improvement was observed with the addition of uterine artery Doppler or the other angiogenic markers. A sensitivity of 45% (95% CI 0.31–0.59) (5% false‐positive rate) and post‐test probability of 11% (95% CI 9–13) were observed using clinical risk variables and PlGF measurement.
Conclusions
Addition of plasma PlGF at 14–16 weeks of gestation to clinical risk assessment improved the identification of nulliparous women at increased risk of developing preterm pre‐eclampsia, but the performance is not sufficient to warrant introduction as a clinical screening test. These findings are marker dependent, not assay dependent; additional markers are needed to achieve clinical utility.
Introduction
We present the first study to critically appraise the quality of reporting of the data analysis step in metabolomics studies since the publication of minimum reporting guidelines in ...2007.
Objectives
The aim of this study was to assess the standard of reporting of the data analysis step in metabolomics biomarker discovery studies and to investigate whether the level of detail supplied allows basic understanding of the steps employed and/or reuse of the protocol. For the purposes of this review we define the data analysis step to include the data pretreatment step and the actual data analysis step, which covers algorithm selection, univariate analysis and multivariate analysis.
Method
We reviewed the literature to identify metabolomic studies of biomarker discovery that were published between January 2008 and December 2014. Studies were examined for completeness in reporting the various steps of the data pretreatment phase and data analysis phase and also for clarity of the workflow of these sections.
Results
We analysed 27 papers, published anytime in 2008 until the end of 2014 in the area or biomarker discovery in serum metabolomics. The results of this review showed that the data analysis step in metabolomics biomarker discovery studies is plagued by unclear and incomplete reporting. Major omissions and lack of logical flow render the data analysis’ workflows in these studies impossible to follow and therefore replicate or even imitate.
Conclusions
While we await the holy grail of computational reproducibility in data analysis to become standard, we propose that, at a minimum, the data analysis section of metabolomics studies should be readable and interpretable without omissions such that a data analysis workflow diagram could be extrapolated from the study and therefore the data analysis protocol could be reused by the reader. That inconsistent and patchy reporting obfuscates reproducibility is a given. However even basic understanding and reuses of protocols are hampered by the low level of detail supplied in the data analysis sections of the studies that we reviewed.
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