401 research outputs found
Prenatal Application of the Individualized Fetal Growth Reference
Get PDFThe individualized reference for defining small for gestational age (SGA) at birth has gained popularity in recent years. However, its utility on fetal assessment has not been evaluated. The authors compare an individualized with an ultrasound reference in predicting poor perinatal outcomes. Data from a large clinical trial in predominantly white US women (1987–1991) with singleton pregnancies (n = 9,526) were used. The individualized reference classified fewer SGA fetuses than the ultrasound reference, but the risks of adverse outcomes were similar between fetuses classified by both references. The risk increased substantially only when the percentiles fell below the 5th percentile (likelihood ratio positive at birth = 2.68 (95% confidence interval (CI): 2.00, 3.58) and 3.13 (95% CI: 2.34, 4.18) for ultrasound and individualized references, respectively). SGA fetuses defined by either the individualized or ultrasound reference alone had risk ratios of adverse outcomes of 1.91 (95% CI: 0.77, 4.77) and 1.18 (95% CI: 0.37, 3.77), respectively, compared with normal fetuses (the difference between these 2 risk ratios, P = 0.71). The authors conclude that neither the ultrasound-based nor the individualized reference does well in predicting adverse perinatal outcomes. The 5th percentile may be a better cutpoint than the 10th percentile in defining SGA
An evaluation of the potential to improve perinatal outcomes by improving antenatal detection of small for gestational age babies in Scotland: a retrospective population cohort study
Get PDFTunable SNAP Microresonators via Internal Ohmic Heating
Get PDFWe demonstrate a thermally tunable Surface Nanoscale Axial Photonics (SNAP) platform. Stable tuning is achieved by heating a SNAP structure fabricated on the surface of a silica capillary with a metal wire positioned inside. Heating a SNAP microresonator with a uniform wire introduces uniform variation of its effective radius which results in constant shift of its resonance wavelengths. Heating with a nonuniform wire allows local nanoscale variation of the capillary effective radius, which enables differential tuning of the spectrum of SNAP structures as well as creation of temporary SNAP microresonators that exist only when current is applied. As an example, we fabricate two bottle microresonators coupled to each other and demonstrate differential tuning of their resonance wavelengths into and out of degeneracy with precision better than 0.2 pm. The developed approach is beneficial for ultraprecise fabrication of tunable ultralow loss parity-time symmetric, optomechanical, and cavity QED devices
Photonic Microresonators Created by Slow Optical Cooking
Get PDFSilica and water are known as exceptionally inert chemical materials whose interaction is not completely understood. Here we show that the effect of this interaction can be significantly enhanced by optical whispering gallery modes (WGMs) propagating in a silica microcapillary filled with water. Our experiments demonstrate that WGMs, which evanescently heat liquid water over several hours, induce permanent alterations in silica material characterized by the subnanometer variation of the WGM spectrum. We use the discovered effect to fabricate optical WGM microresonators having potential applications in optical signal processing and microfluidic sensing. Our results pave the way for the ultraprecise fabrication of resonant optical microdevices and the ultra-accurate characterization of physical and chemical processes at solid-liquid interfaces
Prevalence of maternal smoking and environmental tobacco smoke exposure during pregnancy and impact on birth weight: retrospective study using Millennium Cohort
Get PDF<p>Abstract</p> <p>Background</p> <p>Meta-analyses of studies investigating the impact of maternal environmental tobacco smoke (ETS) on birth weight have not produced robust findings. Although, ante natal ETS exposure probably reduces infant's birth weights, the scale of this exposure remains unknown. We conducted a large, cohort study to assess the impact of ETS exposure on birth weight whilst adjusting for the many factors known to influence this.</p> <p>Method</p> <p>Retrospective study using interview data from parents of 18,297 children born in 2000/2001 and living in the UK 9 months afterwards (the Millennium Cohort Survey). Comparison of birth weight, sex and gestational age specific (SGA) z score, birth before 37 weeks and birth weight < 2.5 Kg (LBW) in infants born to women exposed to: i) no tobacco smoke, ii) ETS only and iii) maternal smoking whilst pregnant.</p> <p>Results</p> <p>13% of UK infants were exposed to ETS and 36% to maternal smoking ante natally. Compared to no ante natal tobacco smoke exposure, domestic ETS lowered infants' adjusted mean birth weights by 36 g (95% CI, 5 g to 67 g) and this effect showed a dose-response relationship. ETS exposure also caused non-significant increases in the adjusted risks of Low Birth Weight (<2.5 Kg) [OR 1.23 (95% CI, 0.96 to 1.58) and premature birth [OR 1.21 (95% CI, 0.96 to 1.51)], whilst the impacts of maternal smoking were greater and statistically significant.</p> <p>Conclusion</p> <p>UK prevalences of domestic ETS exposure and maternal smoking in pregnancy remain high and ETS exposure lowers infants' birth weights.</p
Going to sleep in the supine position is a modifiable risk factor for late pregnancy stillbirth; findings from the New Zealand multicentre stillbirth case-control study
Get PDFObjective: Our objective was to test the primary hypothesis that maternal non-left, in particular supine going-to-sleep position, would be a risk factor for late stillbirth (≥28 weeks of gestation). Methods: A multicentre case-control study was conducted in seven New Zealand health regions, between February 2012 and December 2015. Cases (n=164) were women with singleton pregnancies and late stillbirth, without congenital abnormality. Controls (n=569) were women with on-going singleton pregnancies, randomly selected and frequency matched for health region and gestation. The primary outcome was adjusted odds of late stillbirth associated with self-reported going-to-sleep position, on the last night. The last night was the night before the late stillbirth was thought to have occurred or the night before interview for controls. Going to- sleep position on the last night was categorised as: supine, left-side, right-side, propped or restless. Multivariable logistic regression adjusted for known confounders. Results: Supine going-to-sleep position on the last night was associated with increased late stillbirth risk (adjusted odds ratios (aOR) 3.67, 95% confidence interval (CI) 1.74 to 7.78) with a population attributable risk of 9.4%. Other independent risk factors for late stillbirth (aOR, 95% CI) were: BMI (1.04, 1.01 to 1.08) per unit, maternal age ≥40 (2.88, 1.31 to 6.32), birthweight <10th customised centile (2.76, 1.59 to 4.80), and <6 hours sleep on the last night (1.81, 1.14 to 2.88). The risk associated with supine-going-to sleep position was greater for term (aOR 10.26, 3.00 to 35.04) than preterm stillbirths (aOR 3.12, 0.97 to 10.05). Conclusions: Supine going-to-sleep position is associated with a 3.7 fold increase in overall late stillbirth risk, independent of other common risk factors. A public health campaign encouraging women not to go-to-sleep supine in the third trimester has potential to reduce late stillbirth by approximately 9%
Stillbirth Classification-Developing an International Consensus for Research Executive Summary of a National Institute of Child Health and Human Development Workshop
Get PDFStillbirth is a major obstetric complication, with 3.2 million stillbirths worldwide and 26,000 stillbirths in the United States every year. The Eunice Kennedy Shriver National Institute of Child Health and Human Development held a workshop from October 22-24, 2007, to review the pathophysiology of conditions underlying stillbirth to define causes of death. The optimal classification system would identify the pathophysiologic entity initiating the chain of events that irreversibly led to death. Because the integrity of the classification is based on available pathologic, clinical, and diagnostic data, experts emphasized that a complete stillbirth workup should be performed. Experts developed evidence-based characteristics of maternal, fetal, and placental conditions to attribute a condition as a cause of stillbirth. These conditions include infection, maternal medical conditions, antiphospholipid syndrome, heritable thrombophilias, red cell alloimmunization, platelet alloimmunization, congenital malformations, chromosomal abnormalities including confined placental mosaicism, fetomaternal hemorrhage, placental and umbilical cord abnormalities including vasa previa and placental abruption, complications of multifetal gestation, and uterine complications. In all cases, owing to lack of sufficient knowledge about disease states and normal development, there will be a degree of uncertainty regarding whether a specific condition was indeed the cause of death. (Obstet Gynecol 2009,114:901-14
Cohort profile: Scottish Health and Ethnicity Linkage Study of 4.65 million people exploring ethnic variations in disease in Scotland
Get PDFMany countries require health services to show that
they are meeting the needs of ethnic minority
populations. This requires data on health status,
healthcare uptake and outcomes and population
denominators. Weaknesses in routine data collection
often make such requirements difficult to meet.
Routine data sources in Scotland, as in most countries,
may not include a patient’s ethnicity. In
Scotland, the need for such data is driven by both
policy and legislation responding to rapidly increasing
ethnic diversity. Fair For All (2003), Scotland’s policy,
provides a strategic approach to improve the health of
minority ethnic groups. The UK Race Relations
(Amendment) Act (2000) placed a duty on public
bodies to promote racial equality. These mandates
are reflected in guidance on ethnic monitoring.
Appropriate service and research is undermined by
the lack of data. Ethnic variations occur in all of
Scotland’s national health priority areas, including
coronary heart disease/stroke, cancer, maternal
and child health and mental health.
In view of the mismatch between need for and
availability of data by ethnic group, Bhopal proposed
a demonstration project to explore retrospective
approaches. The project tested proposals including
name search methods, analyses by country of birth,
modelling/extrapolation from other nations’ datasets,
and linkage methods. The demonstration project concluded
that census health records linkage methods—
in the context of this project first mooted by Povey—
held most promise. To our knowledge, attempting
matching of a national health dataset to a complete
national census using demographic identifiers rather
than national identity numbers had not been reported
though health data linkage is well-established in the
UK and internationally, including exploring ethnicity
and health
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