A complex intervention to improve pregnancy outcome in obese women; the UPBEAT randomised controlled trial

Background: Despite the widespread recognition that obesity in pregnant women is associated with adverse outcomes for mother and child, there is no intervention proven to reduce the risk of these complications. The primary aim of this randomised controlled trial is to assess in obese pregnant women, whether a complex behavioural intervention, based on changing diet (to foods with a lower glycemic index) and physical activity, will reduce the risk of gestational diabetes (GDM) and delivery of a large for gestational age (LGA) infant. A secondary aim is to determine whether the intervention lowers the long term risk of obesity in the offspring.Methods/Design: Multicentre randomised controlled trial comparing a behavioural intervention designed to improve glycemic control with standard antenatal care in obese pregnant women.Inclusion criteria; women with a BMI ≥30 kg/m2 and a singleton pregnancy between 15+0 weeks and 18+6 weeks' gestation. Exclusion criteria; pre-defined, pre-existing diseases and multiple pregnancy. Randomisation is on-line by a computer generated programme and is minimised by BMI category, maternal age, ethnicity, parity and centre. Intervention; this is delivered by a health trainer over 8 sessions. Based on control theory, with elements of social cognitive theory, the intervention is designed to improve maternal glycemic control. Women randomised to the control arm receive standard antenatal care until delivery according to local guidelines. All women have a 75 g oral glucose tolerance test at 27+0- 28+6 weeks' gestation.Primary outcome; Maternal: diagnosis of GDM, according to the International Association of Diabetes in Pregnancy Study Group (IADPSG) criteria. Neonatal; infant LGA defined as >90th customised birth weight centile.Sample size; 1546 women to provide 80% power to detect a 25% reduction in the incidence of GDM and a 30% reduction in infants large for gestational age.Discussion: All aspects of this protocol have been evaluated in a pilot randomised controlled trial, with subsequent optimisation of the intervention. The findings of this trial will inform whether lifestyle mediated improvement of glycemic control in obese pregnant women can minimise the risk of pregnancy complications

Haemodynamic changes during human pregnancy

MD ThesisThe aim of this work was to investigate the physiological adaptations that occur in the maternal cardiovascular system during singleton and twin pregnancy. The cardiovascular system has been shown to undergo major adaptations during human pregnancy. Most investigators agreed that cardiac output increased during pregnancy however there was no unanimity regarding the extent and timing of this increase nor about the physiological mechanisms underlying it. Even less was known about the haemodynamic readjustments following delivery and about the alterations in multiple pregnancy. Further study has been limited by the lack of an accurate noninvasive technique which is applicable and reproducible during pregnancy. Cross-sectional echocardiography combined with Doppler ultrasound measurement of blood velocity provides a noninvasive method for measuring cardiac output at a number of locations within the heart and great vessels. Preliminary investigations revealed that cardiac outputs determined by this method correlated closely with those measured by the direct Fick technique in non-pregnant subjects. In addition the method was highly reproducible in both pregnant and nonpregnant subjects. M-mode echocardiography allows accurate and noninvasive measurements of cardiac chamber size and ventricular function. These measurements were also found to be highly reproducible in pregnant and non-pregnant subjects. Using these techniques the aims of this thesis were to investigate the extent, timing and mechanisms of the changes in cardiac output during singleton and twin pregnancy. Echocardiographic investigations were performed prior to and during singleton pregnancy, during the first 6 months after singleton pregnancy, and during and 6 months after twin pregnancy. All subjects were studied in the left semi-lateral position. The results suggested that; (1) During singleton pregnancy cardiac output was increased early in the first trimester and continued to rise until 24 weeks gestation when values were 43-49% above pre-pregnant control values. Thereafter there was no further change. Heart rate and left ventricular function increased during the first trimester. Left atrial and left ventricular end-diastolic dimensions increased during the second trimester suggesting an increase in venous return. Cardiac valve cross-sectional areas and left ventricular wall thickness also increased during pregnancy. After delivery cardiac output had fallen to non-pregnant values by 2 weeks. This was associated with reductions in left ventricular performance and left atrial and left ventricular end-diastolic dimensions. The decrease in valve cross-sectional areas and left ventricular wall thickness was not evident until later in the puerperium. (2) During twin pregnancy cardiac output was increased by 20 weeks gestation and thereafter showed no further change. Maximum cardiac output was 59-62% above postnatal control values. This increase was greater than that recorded during singleton pregnancy due to a relatively greater increase in heart rate. Twin pregnancy was also associated with a greater increase in left atrial dimension. The results of these studies shed light on some of the the unanswered questions in the field of maternal haemodynamics. The noninvasive Doppler techniques used allowed accurate and reproducible measurements of cardiac output in pregnant subjects. This work has important implications for the future investigation of cardiac and hypertensive disorders during pregnancy.Newcastle Health Authority: Birthright

'This line across my belly...' Studies in caesarean section

Stephen Robson undertook a number of studies of caesarean section. He found that age is the largest single contributor to rising rates, and that male partners influence decisions about birth. Psychological problems increase the risk of caesarean. Further studies are needed

A new methodology for network scale simulation of emerging power line communication standards

This paper presents the development of a new methodology for the simulation of Power Line Communication (PLC) within the popular Electromagnetic Transients Programme-Alternative Transients Programme (EMTP-ATP). As a first application, the comparative performance of the emerging Orthogonal Frequency Division Multiplexing (OFDM) based Prime and G3-PLC narrowband standards is investigated. Models of both standards have been created within the EMTP-ATP and simulations performed using frequency dependent line models and realistic transformer models as terminations. It is observed that both standards are severely affected by the highly frequency selective nature of the MV power line channel and a more considered choice of OFDM parameters may be necessary for optimal performance on MV networks

Clinical Cases in Obstetrics, Gynaecology and Women's Health

An updated edition for our popular Clinical Cases collection, this book is aimed medical students following the core curriculum in Australia and New Zealand; and the United Kingdom, junior doctors at resident or house officer level, and general practitioners. This handy, lab coat pocket-sized book broadly covers the whole syllabus for the medical student, and the whole range of obstetric and gynaecological problems likely to come into the path of the busy junior hospital doctor or general practitioner, but it is not a textbook providing simply a list of differential diagnoses and treatments. The approach has been developed from the experienced authors teaching of problem-based learning scenarios (PBLs) to clinical students. PBLs introduce students to typical clinical situations and then encourage those students to think about how they would take appropriate histories, examine, investigate and finally treat their patients. In this book, by using case histories that are more developed and complex, we aim to show readers in greater detail how women may present with particular conditions, and demonstrate what should take place in the way of consultation, investigations and treatment. However, by questioning our readers as we go along we also hope to encourage them to think about why they would choose a certain clinical course of action and to base their decisions firmly on current scientific evidence. In addition to the purely clinical aspects of the cases, the emotional, social and psychological aspects of the care of each woman is described. Each of the 50 case histories commences with a straightforward description following a woman through the clinical presentation of a particular condition. Along the way, important points in clinical examination and diagnosis, complications, investigations and management are incorporated into the text as a conversation with the reader, and essential points are highlighted in boxes. Being an Australian author team, tips are included for those junior doctors faced with obstetric or gynaecological problems in a smaller metropolitan or rural setting - facilities for care and the advice of senior practitioners may be more limited in such surroundings and different care paths may be more appropriate, especially in remote parts of Australia

Recurring patterns in stationary intervals of abdominal uterine electromyograms during gestation

Abdominal uterine electromyograms (uEMG) studies have focused on uterine contractions to describe the evolution of uterine activity and preterm birth (PTB) prediction. Stationary, non-contracting uEMG has not been studied. The aim of the study was to investigate the recurring patterns in stationary uEMG, their relationship with gestation age and PTB, and PTB predictivity. A public database of 300 (38 PTB) three-channel (S1-S3) uEMG recordings of 30 min, collected between 22 and 35 weeks' gestation, was used. Motion and labour contraction-free intervals in uEMG were identified as 5-min weak-sense stationarity intervals in 268 (34 PTB) recordings. Sample entropy (SampEn), percentage recurrence (PR), percentage determinism (PD), entropy (ER), and maximum length (L MAX) of recurrence were calculated and analysed according to the time to delivery and PTB. Random time series were generated by random shuffle (RS) of actual data. Recurrence was present in actual data (p<0.001) but not RS. In S3, PR (p<0.005), PD (p<0.01), ER (p<0.005), and L MAX (p<0.05) were higher, and SampEn lower (p<0.005) in PTB. Recurrence indices increased (all p<0.001) and SampEn decreased (p<0.01) with decreasing time to delivery, suggesting increasingly regular and recurring patterns with gestation progression. All indices predicted PTB with AUC≥0.62 (p<0.05). Recurring patterns in stationary non-contracting uEMG were associated with time to delivery but were relatively poor predictors of PTB

Antenatal telephone support intervention with and without uterine artery Doppler screening for low risk nulliparous women: a randomised controlled trial

BACKGROUND: The number of routine antenatal visits provided to low risk nulliparous women has been reduced in the UK, acknowledging this change in care may result in women being less satisfied with their care and having poorer psychosocial outcomes. The primary aim of the study was to investigate whether the provision of proactive telephone support intervention (TSI) with and without uterine artery Doppler screening (UADS) would reduce the total number of antenatal visits required. A secondary aim was to investigate whether the interventions affected psychological outcomes. METHODS: A three-arm randomised controlled trial involving 840 low risk nulliparous women was conducted at a large maternity unit in North East England. All women received antenatal care in line with current UK guidance. Women in the TSI group (T) received calls from a midwife at 28, 33 and 36 weeks and women in the telephone and Doppler group (T + D) received the TSI and additional UADS at 20 weeks’ gestation. The main outcome measure was the total number of scheduled and unscheduled antenatal visits received after 20 weeks’ gestation. RESULTS: The median number of unscheduled (n = 2.0), scheduled visits (n = 7.0) and mean number of total visits (n = 8.8) were similar in the three groups. The majority (67%) of additional antenatal visits were made to a Maternity Assessment Unit because of commonly occurring pregnancy complications. Additional TSI+/–UADS was not associated with differences in clinical outcomes, levels of anxiety, social support or satisfaction with care. There were challenges to the successful delivery of the telephone support intervention; 59% of women were contacted at 29 and 33 weeks gestation reducing to 52% of women at 37 weeks. CONCLUSIONS: Provision of additional telephone support (with or without UADS) in low risk nulliparous women did not reduce the number of unscheduled antenatal visits or reduce anxiety. This study provides a useful insight into the reasons why this client group attend for unscheduled visits. TRIAL REGISTRATION: ISRCTN6235458

Non-contact measurement and analysis of trapped charge decay rates for cable line switching transients

During reclosure of 275 kV cable circuits used for voltage control, excessive overvoltages were observed on the network. Such events cause onerous and costly failures. Transient simulations have shown that the normal voltage on its own cannot generate such excessive switching overvoltages. Initial investigations by the network operator pointed towards trapped charge on the unearthed as the cause of the failures. Measurement of these trapped charge voltages and their slow decay without interfering with the charge has, to the author’s knowledge, not been done before in an operational substation. This work introduces a technique to measure trapped charge at a 275 kV substation using the Electrostatic Field Mill. Since the electric field is a proxy measurement of surface voltage, field mills can also be used to measure voltage. In this paper, an on-site substation measurement setup using an electrostatic field mill has been developed for the non-contact measurement of trapped charge voltage on a 275 kV underground cable circuit following switching operations at a National Grid substation. Results of field measurements within the substation and laboratory experimentation are discussed. It is demonstrated that with adequate calibration, achieved by using the known pre-switching power frequency steady state voltage, the slowly decaying DC voltage caused by the cable trapped charge can be measured using this non-contact technique. The correlation between the instantaneous time constant and the relative humidity is also analysed

Response to comment on "solid recovered fuel: Materials flow analysis and fuel property development during the mechanical processing of biodried waste"

Laner and Cencic1 comment on Velis et al. (2013)2 clarifying certain points on the use of the material flow analysis (MFA) software STAN3. We welcome the correspondence and the opportunity this exchange provides to discuss optimal approaches to using STAN. In keeping with Velis et al.2 these physically impossible, and otherwise insignificant, negative flows have enabled improvements to STAN. Here, we elaborate on the practicalities of using STAN in our research and on the correctness and validation of our results, notwithstanding the inclusion of negative flows. We explain the contribution of our approach to solid waste management and resource recovery