Derek Tuffnell

Ambient air pollution and low birthweight: a European cohort study (ESCAPE)

BACKGROUNDnAmbient air pollution has been associated with restricted fetal growth, which is linked with adverse respiratory health in childhood. We assessed the effect of maternal exposure to low concentrations of ambient air pollution on birthweight.nnnMETHODSnWe pooled data from 14 population-based mother-child cohort studies in 12 European countries. Overall, the study population included 74u2008178 women who had singleton deliveries between Feb 11, 1994, and June 2, 2011, and for whom information about infant birthweight, gestational age, and sex was available. The primary outcome of interest was low birthweight at term (weight <2500 g at birth after 37 weeks of gestation). Mean concentrations of particulate matter with an aerodynamic diameter of less than 2·5 μm (PM2·5), less than 10 μm (PM10), and between 2·5 μm and 10 μm during pregnancy were estimated at maternal home addresses with temporally adjusted land-use regression models, as was PM2·5 absorbance and concentrations of nitrogen dioxide (NO2) and nitrogen oxides. We also investigated traffic density on the nearest road and total traffic load. We calculated pooled effect estimates with random-effects models.nnnFINDINGSnA 5 μg/m(3) increase in concentration of PM2·5 during pregnancy was associated with an increased risk of low birthweight at term (adjusted odds ratio [OR] 1·18, 95% CI 1·06-1·33). An increased risk was also recorded for pregnancy concentrations lower than the present European Union annual PM2·5 limit of 25 μg/m(3) (OR for 5 μg/m(3) increase in participants exposed to concentrations of less than 20 μg/m(3) 1·41, 95% CI 1·20-1·65). PM10 (OR for 10 μg/m(3) increase 1·16, 95% CI 1·00-1·35), NO2 (OR for 10 μg/m(3) increase 1·09, 1·00-1·19), and traffic density on nearest street (OR for increase of 5000 vehicles per day 1·06, 1·01-1·11) were also associated with increased risk of low birthweight at term. The population attributable risk estimated for a reduction in PM2·5 concentration to 10 μg/m(3) during pregnancy corresponded to a decrease of 22% (95% CI 8-33%) in cases of low birthweight at term.nnnINTERPRETATIONnExposure to ambient air pollutants and traffic during pregnancy is associated with restricted fetal growth. A substantial proportion of cases of low birthweight at term could be prevented in Europe if urban air pollution was reduced.nnnFUNDINGnThe European Union.

Treatments for gestational diabetes

BACKGROUNDnGestational diabetes (GDM) affects 3% to 6% of all pregnancies. Women are often intensively managed with increased obstetric monitoring, dietary regulation, and insulin. However, there has been no sound evidence base to support intensive treatment. The key issue for clinicians and consumers is whether treatment of GDM improves perinatal outcome.nnnOBJECTIVESnTo compare the effect of alternative treatment policies for GDM on both maternal and infant outcomes.nnnSEARCH STRATEGYnWe searched the Cochrane Pregnancy and Childbirth Groups Trials Register (January 2009) and bibliographies of relevant papers.nnnSELECTION CRITERIAnRandomised controlled trials comparing alternative management strategies for women with GDM and impaired glucose tolerance in pregnancy.nnnDATA COLLECTION AND ANALYSISnTwo authors and a member of the Cochrane Pregnancy and Childbirth Groups editorial team extracted and checked data independently. Disagreements were resolved through discussion with the third author.nnnMAIN RESULTSnEight randomised controlled trials (1418 women) were included.Caesarean section rate was not significantly different when comparing any specific treatment with routine antenatal care (ANC) including data from five trials with 1255 participants (risk ratio (RR) 0.94, 95% confidence interval (CI) 0.80 to 1.12). However, when comparing oral hypoglycaemics with insulin as treatment for GDM, there was a significant reduction (RR 0.46, 95% CI 0.27 to 0.77, two trials, 90 participants). There was a reduction in the risk of pre-eclampsia with intensive treatment (including dietary advice and insulin) compared to routine ANC (RR 0.65, 95% CI 0.48 to 0.88, one trial, 1000 participants). More women had their labours induced when given specific treatment compared to routine ANC (RR 1.33, 95% CI 1.13 to 1.57, two trials, 1068 participants). The composite outcome of perinatal morbidity (death, shoulder dystocia, bone fracture and nerve palsy) was significantly reduced for those receiving intensive treatment for mild GDM compared to routine ANC (RR 0.32, 95% CI 0.14 to 0.73, one trial, 1030 infants).There was a reduction in the proportion of infants weighing more than 4000 grams (RR 0.46, 95% CI 0.34 to 0.63, one trial, 1030 infants) and the proportion of infants weighing greater than the 90th birth centile (RR 0.55, 95% CI 0.30 to 0.99, three trials, 223 infants) of mothers receiving specific treatment for GDM compared to routine ANC. However, there was no statistically significant difference in this proportion between infants of mothers receiving oral drugs compared to insulin as treatment for GDM.nnnAUTHORS CONCLUSIONSnSpecific treatment including dietary advice and insulin for mild GDM reduces the risk of maternal and perinatal morbidity. However, it is associated with higher risk of labour induction. More research is needed to assess the impact of different types of intensive treatment, including oral drugs and insulin, on individual short- and long-term infant outcomes.

Cohort Profile: The Born in Bradford multi-ethnic family cohort study

Bradford Institute for Health Research, Bradford Teaching Hospitals Foundation Trust, Bradford, UK, School of Health Studies, University of Bradford, Bradford, UK, Edinburgh Ethnicity and Health Research Group, Centre for Population Health Sciences, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, UK, School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire, UK, Medical Research Council Centre for Causal Analyses in Translational Epidemiology, School of Social and Community Medicine, University of Bristol, Bristol, UK, Paediatric Epidemiology Group, Centre for Epidemiology and Biostatistics, Leeds Institute of Genetics, Health and Therapeutics, Faculty of Medicine and Health, University of Leeds, Leeds, UK and Department of Health Sciences, University of York, York, UK

Interval between decision and delivery by caesarean section-are current standards achievable? Observational case series.

Abstract Objectives: To audit interval from decision to delivery in urgent caesarean section to determine whether the current standard of 30 minutes is achievable routinely; to determine whether delay leads to an excess of admissions to special care. Design: Three audit cycles over four years followed by a continuous audit over 32 months. Setting: Large district general hospital delivering 5500 women each year. Participants: All women delivered by urgent caesarean section for abnormal fetal heart rate patterns, cord prolapse, failed instrumental delivery, or suspected placental abruption. Main outcome measures: Proportion of women delivered within 30 and 40 minutes of decision. Admission rates to special care by length of interval between decision and delivery. Results: In the continuous audit 478 of 721 (66.3%) women were delivered in 30 minutes and 637 (88.3%) within 40 minutes; 29 (4.0%) were undelivered at 50 minutes. If the woman was taken to theatre in 10 minutes, 409 of 500 (81.8%) were delivered in 30 minutes and 495 (97%) in 40 minutes. There was no significant difference in the proportion of babies born at 36 weeks or later who were admitted to special care, when analysed by interval from decision to delivery. 36/449 (8%) babies with an interval from decision to delivery of less than 30 minutes were admitted to special care and 3/23 (13%) with an interval of more than 50 minutes were admitted. Conclusions: The current recommendations for the interval between decision and delivery are not being achieved in routine practice. Failure to meet the recommendations does not seem to increase neonatal morbidity. What is already known on this topic Many national bodies recommend that when a decision is made to deliver a baby by caesarean section because of fetal distress, the baby should be delivered within 30 minutes There are no clear classifications of what is urgent nor any evidence that this standard is achievable in routine practice What this study adds Delivery within 30 minutes is achievable in only two out of three cases; 88% will be delivered in 40 minutes; up to 4% of women will remain undelivered at 50 minutes Delay in delivery made no difference to the rate of admission to special care for babies over 36 weeks gestation

A randomised double blind placebo controlled trial of fish oil in high risk pregnancy

Objective To determine whether n‐3 fatty acid (EPA/DCHA) prophylaxis is beneficial in high risk pregnancies.

Outcomes of severe pre-eclampsia/eclampsia in Yorkshire 1999/2003

Objectiveu2003 To establish the risk of serious complications from severe pre‐eclampsia and eclampsia in a region using a common guideline for the management of these conditions.

The UK Obstetric Surveillance System for rare disorders of pregnancy.

A new UK Obstetric Surveillance System (UKOSS) has recently been launched to investigate uncommon disorders of pregnancy. UKOSS is a joint initiative of the Royal College of Obstetricians and Gynaecologists and the National Perinatal Epidemiology Unit and has the backing of the Royal College of Midwives, the Faculty of Public Health, the Health Protection Agency and the Department of Health Patient Safety Research Programme. Many uncommon disorders of pregnancy are difficult to study because routine information sources are unreliable, and comprehensive studies, such as the BEST survey of eclampsia in 1992, require a large collaboration to identify relatively few cases. Information requests from multiple sources about different problems can overburden reporting clinicians. Many rare disorders are also ‘near-miss’ events, ‘a severe life-threatening obstetric complication necessitating an urgent medical intervention in order to prevent likely death of the mother’. The 50 years of triennial Confidential Enquiries into UK maternal deaths have led to many important changes in care, but the authors of recent reports have suggested that study of ‘near-miss’ events may be useful. The reporting can be faster, and the number of cases studied larger, than when deaths alone are considered. The quality of care in maternal deaths and near-misses can be compared, risk factors identified and information to improve service planning provided. Over the last 20 years the British Paediatric Surveillance Unit (BPSU) has developed a reliable method to study uncommon disorders of childhood. BPSU surveys have informed policy on antenatal screening, documented the association between Reye’s syndrome and aspirin, identified the risks of faulty packaging of chemistry sets and investigated concerns about vitamin K therapy, water-births and variant CJD in British children. UKOSS will use similar methods to the BPSU, namely a prospective monthly case-collection scheme. Each hospital with a consultant obstetric unit will nominate four individuals (obstetrician, midwife, anaesthetist and perinatal risk management co-ordinator) who will be sent a monthly report card with a list of conditions currently under surveillance (Fig. 1). Only conditions with an estimated incidence of fewer than one in 2000 births will be surveyed, and thus the most common response will be a nil return. The methods to identify women who should be reported to UKOSS may include discussing the list at regular perinatal mortality and morbidity meetings. Conditions that are on existing perinatal risk ‘trigger event’ lists will be notified already to the perinatal risk co-ordinator. Women with fatal disorders will be identified through CEMACH midwives. Women affected by some of the conditions studied will not necessarily be seen at the time of diagnosis in obstetric departments; for example, women with tuberculosis or antenatal pulmonary embolism. However, they will be treated for these disorders throughout the remainder of their pregnancy and unless they lose the pregnancy at an early stage will be cared for by obstetric and midwifery staff after the acute event. In order to ensure complete data collection, reporting staff will be asked to notify women with these disorders as soon as they become aware of the condition, whether or not they were caring for the woman at the time of her first diagnosis. On receiving a case report (return of the monthly card mailing), the UKOSS team will dispatch a form to collect more detailed information. These have been developed individually for each condition and are designed to be short and easily completed from a woman’s case notes without requiring reference to any other sources of information. They seek confirmation of the appropriate case definition and additional information on risk factors, management and outcomes according to the protocol relating to each condition. UKOSS will not collect any personally identifiable information, such as names, addresses, dates of birth or hospital numbers. Reporting clinicians will only be asked to keep their own record of the names of women they have reported, in order that they can retrieve the woman’s case notes to complete the data collection form. The London Multi-centre Research Ethics Committee has approved the collection of anonymised information in this way without seeking the consent of individual women. In order to perform case–control studies, UKOSSwill also collect anonymised information on control women for some surveys. For these studies only, clinicians who report a case will also be asked to identify one or two appropriate control women and complete a similar data collection form from their case notes. The process of selecting control women will be individual for each study. For example, for one of the studies running during the first year, peripartum hysterectomy, clinicians will be asked to identify the two women who delivered in the same hospital immediately before the case was delivered. Results will be presented in quarterly newsletters, an annual report and peer-reviewed publications. BJOG: an International Journal of Obstetrics and Gynaecology March 2005, Vol. 112, pp. 263–265

Measuring placental transfusion for term births: weighing babies with cord intact

Please cite this paper as: Farrar D, Airey R, Law G, Tuffnell D, Cattle B, Duley L. Measuring placental transfusion for term births: weighing babies with cord intact. BJOG 2011;118:70–75.

Treatments for gestational diabetes and impaired glucose tolerance in pregnancy

BACKGROUNDnGestational diabetes and impaired glucose tolerance (IGT) in pregnancy affects between 3 and 6% of all pregnancies and both have been associated with pregnancy complications. A lack of conclusive evidence has led clinicians to equate the risk of adverse perinatal outcome with pre-existing diabetes. Consequently, women are often intensively managed with increased obstetric monitoring, dietary regulation, and in some cases insulin therapy. However, there has been no sound evidence base to support intensive treatment. The key issue for clinicians and consumers is whether treatment of gestational diabetes and IGT will improve perinatal outcome.nnnOBJECTIVESnThe objective of this review was to compare alternative policies of care for women with gestational diabetes and IGT in pregnancy.nnnSEARCH STRATEGYnWe searched the Cochrane Pregnancy and Childbirth Group trials register (12 September 2002) and the bibliographies of relevant papers. The Cochrane Central Register of Controlled Trials was also searched (The Cochrane Library, Issue 3, 2002).nnnSELECTION CRITERIAnRandomised controlled trials comparing alternative management strategies for women with gestational diabetes and IGT in pregnancy.nnnDATA COLLECTION AND ANALYSISnQuality was assessed according to the criteria defined by the Cochrane Reviewers Handbook. Data were extracted and checked independently by two reviewers. Any disagreements were resolved through discussion with the third reviewer.nnnMAIN RESULTSnThree studies with a total of 223 women were included. All three included studies involved women with IGT. No trials reporting treatments for gestational diabetes met the criteria. There are insufficient data for any reliable conclusions about the effect of treatments for IGT on perinatal outcome. The difference in abdominal operative delivery rates is not statistically significant (relative risk (RR) 0.86, 95% confidence interval 0.51 to 1.45) and the effect on special care baby unit admission is also not significant (RR 0.49, 95% confidence interval (CI) 0.19 to 1.24). Reduction in birthweight greater than 90th centile (RR 0.55, 95% CI 0.19 to 1.61) was not found to be significant. This review suggests that an interventionist policy of treatment may be associated with a reduced risk of neonatal hypoglycaemia (RR 0.25, 95% CI 0.07 to 0.86). No other statistically significant differences were detected. A number of outcomes are only reported by one study resulting in a small sample and wide confidence intervals.nnnREVIEWERS CONCLUSIONSnThere are insufficient data for any reliable conclusions about the effects of treatments for impaired glucose tolerance on perinatal outcome.

Continuous subcutaneous insulin infusion versus multiple daily injections of insulin for pregnant women with diabetes.

BACKGROUNDnDiabetes results in a rise in blood glucose above normal physiological levels; if untreated this may cause damage to many systems including the cardiovascular and renal systems. Pregnancy increases resistance to insulin action; for those women who have pre-gestational diabetes, this results in an increasing insulin requirement. There are several methods of administering insulin. Conventionally, insulin has been administered subcutaneously, formally referred to as intensive conventional treatment, but now more usually referred to as multiple daily injections (MDI). An alternative method of insulin administration is the continuous subcutaneous insulin infusion pump (CSII).nnnOBJECTIVESnTo compare CSII with MDI of insulin for pregnant women with pre-existing and gestational diabetes.nnnSEARCH METHODSnWe searched the Cochrane Pregnancy and Childbirth Groups Trials Register (31 March 2016) and reference lists of retrieved studies.nnnSELECTION CRITERIAnRandomised trials comparing CSII with MDI for pregnant women with diabetes.nnnDATA COLLECTION AND ANALYSISnThree review authors independently assessed studies and two review authors extracted data. Disagreements were resolved through discussion with the third author. We assessed the quality of the evidence using the GRADE approach.nnnMAIN RESULTSnWe included five single-centre trials (undertaken in Italy) with 153 women and 154 pregnancies in this review.There were no clear differences in the primary outcomes reported between CSII and MDI in the included trials: caesarean section (risk ratio (RR) 1.09, 95% confidence interval (CI) 0.66 to 1.77; three trials, 71 women, evidence graded very low), large-for-gestational age (RR 4.15, 95% CI 0.49 to 34.95; three trials, 73 infants; evidence graded very low), and perinatal mortality (RR 2.33, 95% CI 0.38 to 14.32; four trials, 83 infants, evidence graded very low). Other primary outcomes were not reported in these trials (hypertensive disorders of pregnancy, development of type 2 diabetes, composite outcome of serious neonatal outcomes, and neurosensory disability).There was no clear evidence of differences in the maternal secondary outcomes: maternal weight gain during pregnancy, 24 hour mean blood glucose in each trimester, mean maternal HbA1c in each trimester, maternal hypoglycaemia, and maternal hyperglycaemia. The included studies did not report several GRADE outcomes: perineal trauma, return to pre-pregnancy weight, postnatal depression, induction of labour. Many maternal secondary outcomes were also not reported.In two trials, including a total of 61 infants, CSII was associated with an increase in mean birthweight compared with MDI (mean difference (MD) 220.56 g, 95% CI -2.09 g to 443.20 g; P = 0.05). However, the large CI including anything from a small reduction to an increase in mean birthweight and the lack of a difference in macrosomia rate (RR 3.20, CI 0.14 to 72.62; two trials, 61 infants) suggests uncertainty. Large-for-gestational age (see above), andsmall-for-gestational age also suggests uncertainty of effect. No significant differences were found in: gestation at delivery, preterm birth < 37 weeks gestation, preterm birth < 32 weeks gestation, neonatal hypoglycaemia (evidence graded very low), respiratory distress syndrome, neonatal hyperbilirubinaemia, and fetal anomaly. There were no data reported on many important infant outcomes, including the GRADE outcomes adiposity and diabetes. There was no follow-up of infants in childhood or adulthood, so longer-term outcomes were not reported.The only outcome reported for use of health service resources wasmaternal days hospitalised, which did not show a difference between groups in the small number of women included (MD 9.40, CI -6.04 to 24.84; one trial, 10 women).The methods used by the trials were poorly reported, for example although blinding of participants and clinicians regarding intervention allocation is impossible, it is possible to blind assessors and this along with other aspects of trial methods was not reported, which means that the trials are at an unclear or high risk of bias. We do not know if the women who participated were representative, and therefore if the results can be generalised. Most GRADE outcomes were not reported. For the GRADE outcomes that were reported, our assessment was that the evidence is very low quality (caesarean section, large-for-gestational age, perinatal mortality, andneonatal hypoglycaemia). This was due to design limitations in the included trials, small sample sizes in the trials contributing data, wide CIs crossing both the line of no effect and the line of appreciable benefit and/or harm, and often few events. We are therefore uncertain whether CSII or MDI improves outcomes for pregnant women with diabetes and their infants, and the results of further studies may differ substantially from those presented in this review.nnnAUTHORS CONCLUSIONSnThere is no evidence to support the use of one particular form of insulin administration over another for pregnant women with diabetes. There are only a small number of trials appropriate for meta-analysis, a small number of women included and questionable generalisability of the trial population.Pump technology has progressed since these trials were undertaken. Well-designed randomised trials are required to evaluate comparisons such as patch pumps against MDI and more conventional CSII against MDI. These trials should be adequately powered to assess the effect of interventions, and report the core set of outcomes used in Cochrane reviews of diabetes in pregnancy. Trials to assess the effects of pumps on birthweight and macrosomia rates are needed. It would be beneficial for future trials to undertake longer-term follow-up of participants and their infants, assess womens preferences, and conduct an economic evaluation.