Making stillbirths visible: a systematic review of globally reported causes of stillbirth

BACKGROUND

Stillbirth is a global health problem. The World Health Organization (WHO) application of the International Classification of Diseases for perinatal mortality (ICD-PM) aims to improve data on stillbirth to enable prevention.

OBJECTIVES

To identify globally reported causes of stillbirth, classification systems, and alignment with the ICD-PM.

SEARCH STRATEGY

We searched CINAHL, EMBASE, Medline, Global Health, and Pubmed from 2009 to 2016.

SELECTION CRITERIA

Reports of stillbirth causes in unselective cohorts.

DATA COLLECTION AND ANALYSIS

Pooled estimates of causes were derived for country representative reports. Systems and causes were assessed for alignment with the ICD-PM. Data are presented by income setting (low, middle, and high income countries; LIC, MIC, HIC).

MAIN RESULTS

Eighty-five reports from 50 countries (489 089 stillbirths) were included. The most frequent categories were Unexplained, Antepartum haemorrhage, and Other (all settings); Infection and Hypoxic peripartum (LIC), and Placental (MIC, HIC). Overall report quality was low. Only one classification system fully aligned with ICD-PM. All stillbirth causes mapped to ICD-PM. In a subset from HIC, mapping obscured major causes.

CONCLUSIONS

There is a paucity of quality information on causes of stillbirth globally. Improving investigation of stillbirths and standardisation of audit and classification is urgently needed and should be achievable in all well-resourced settings. Implementation of the WHO Perinatal Mortality Audit and Review guide is needed, particularly across high burden settings.

FUNDING

HR, SH, SHL, and AW were supported by an NHMRC-CRE grant (APP1116640). VF was funded by an NHMRC-CDF (APP1123611).

TWEETABLE ABSTRACT

Urgent need to improve data on causes of stillbirths across all settings to meet global targets.

PLAIN LANGUAGE SUMMARY

Background and methods Nearly three million babies are stillborn every year. These deaths have deep and long-lasting effects on parents, healthcare providers, and the society. One of the major challenges to preventing stillbirths is the lack of information about why they happen. In this study, we collected reports on the causes of stillbirth from high-, middle-, and low-income countries to: (1) Understand the causes of stillbirth, and (2) Understand how to improve reporting of stillbirths. Findings We found 85 reports from 50 different countries. The information available from the reports was inconsistent and often of poor quality, so it was hard to get a clear picture about what are the causes of stillbirth across the world. Many different definitions of stillbirth were used. There was also wide variation in what investigations of the mother and baby were undertaken to identify the cause of stillbirth. Stillbirths in all income settings (low-, middle-, and high-income countries) were most frequently reported as Unexplained, Other, and Haemorrhage (bleeding). Unexplained and Other are not helpful in understanding why a baby was stillborn. In low-income countries, stillbirths were often attributed to Infection and Complications during labour and birth. In middle- and high-income countries, stillbirths were often reported as Placental complications. Limitations We may have missed some reports as searches were carried out in English only. The available reports were of poor quality. Implications Many countries, particularly those where the majority of stillbirths occur, do not report any information about these deaths. Where there are reports, the quality is often poor. It is important to improve the investigation and reporting of stillbirth using a standardised system so that policy makers and healthcare workers can develop effective stillbirth prevention programs. All stillbirths should be investigated and reported in line with the World Health Organization standards.

Changes in management policies for extremely preterm births and neonatal outcomes from 2003 to 2012: two population-based studies in ten European regions

OBJECTIVE

To investigate changes in maternity and neonatal unit policies towards extremely preterm infants (EPTIs) between 2003 and 2012, and concurrent trends in their mortality and morbidity in ten European regions.

DESIGN

Population-based cohort studies in 2003 (MOSAIC study) and 2011/2012 (EPICE study) and questionnaires from hospitals.

SETTING

70 hospitals in ten European regions.

POPULATION

Infants born at <27 weeks of gestational age (GA) in hospitals participating in both the MOSAIC and EPICE studies (1240 in 2003, 1293 in 2011/2012).

METHODS

We used McNemar's Chi² test, paired t-tests and conditional logistic regression for comparisons over time.

MAIN OUTCOMES MEASURES

Reported policies, mortality and morbidity of EPTIs.

RESULTS

The lowest GA at which maternity units reported performing a caesarean section for acute distress of a singleton non-malformed fetus decreased from an average of 24.7 to 24.1 weeks (P < 0.01) when parents were in favour of active management, and 26.1 to 25.2 weeks (P = 0.01) when parents were against. Units reported that neonatologists were called more often for spontaneous deliveries starting at 22 weeks GA in 2012 and more often made decisions about active resuscitation alone, rather than in multidisciplinary teams. In-hospital mortality after live birth for EPTIs decreased from 50% to 42% (P < 0.01). Units reporting more active management in 2012 than 2003 had higher mortality in 2003 (55% versus 43%; P < 0.01) and experienced larger declines (55 to 44%; P < 0.001) than units where policies stayed the same (43 to 37%; P = 0.1).

CONCLUSIONS

European hospitals reporting changes in management policies experienced larger survival gains for EPTIs.

TWEETABLE ABSTRACT

Changes in reported policies for management of extremely preterm births were related to mortality declines.

Prevention of neural tube defects in the UK: a missed opportunity

OBJECTIVE

In 1991, the Medical Research Council (MRC) Vitamin Study demonstrated that folic acid taken before pregnancy and in early pregnancy reduced the risk of a neural tube defect (NTD). We aimed to estimate the number of NTD pregnancies that would have been prevented if flour had been fortified with folic acid in the UK from 1998 as it had been in the USA.

DESIGN

Estimates of NTD prevalence, the preventive effect of folic acid and the proportion of women taking folic acid supplements before pregnancy were used to predict the number of NTD pregnancies that would have been prevented if folic acid fortification had been implemented.

SETTING

Eight congenital anomaly registers in England and Wales.

MAIN OUTCOME MEASURES

The prevalence of pregnancies with an NTD in the UK and the number of these pregnancies that would have been prevented if folic acid fortification had been implemented.

RESULTS

From 1991 to 2012, the prevalence of NTD pregnancies was 1.28 (95% CI 1.24 to 1.31) per 1000 total births (19% live births, 81% terminations and 0.5% stillbirths and fetal deaths ≥20 weeks' gestation). If the USA levels of folic acid fortification from 1998 onwards had been adopted in the UK, an estimated 2014 fewer NTD pregnancies would have occurred.

CONCLUSIONS

Failure to implement folic acid fortification in the UK has caused, and continues to cause, avoidable terminations of pregnancy, stillbirths, neonatal deaths and permanent serious disability in surviving children.

The effects of a one-to-one nurse-to-patient ratio on the mortality rate in neonatal intensive care: a retrospective, longitudinal, population-based study

OBJECTIVE

To estimate the effect of the provision of a one-to-one nurse-to-patient ratio on mortality rates in neonatal intensive care units.

DESIGN

A population-based analysis of operational clinical data using an instrumental variable method.

SETTING

National Health Service neonatal units in England contributing data to the National Neonatal Research Database at the Neonatal Data Analysis Unit and participating in the Neonatal Economic, Staffing, and Clinical Outcomes Project.

PARTICIPANTS

43 tertiary-level neonatal units observed monthly over the period January 2008 to December 2012.

INTERVENTION

Proportion of neonatal intensive care days or proportion of intensive care admissions for which one-to-one nursing was provided.

OUTCOMES

Monthly in-hospital intensive care mortality rate.

RESULTS

Over the study period, the provision of one-to-one nursing in tertiary neonatal units declined from a median of 9.1% of intensive care days in 2008 to 5.9% in 2012. A 10 percentage point decrease in the proportion of intensive care days on which one-to-one nursing was provided was associated with an increase in the in-hospital mortality rate of 0.6 (95% CI 1.2 to 0.0) deaths per 100 infants receiving neonatal intensive care per month compared with a median monthly mortality rate of 4.5 deaths per 100 infants per month. The results remained robust to sensitivity analyses that varied the estimation sample of units, the choice of instrumental variables, unit classification and the selection of control variables.

CONCLUSIONS

Our study suggests that decreases in the provision of one-to-one nursing in tertiary-level neonatal intensive care units increase the in-hospital mortality rate.

Economic costs associated with moderate and late preterm birth: a prospective population-based study

OBJECTIVE

We sought to determine the economic costs associated with moderate and late preterm birth.

DESIGN

An economic study was nested within a prospective cohort study.

SAMPLE

Infants born between 32(+0) and 36(+6)  weeks of gestation in the East Midlands of England. A sample of infants born at ≥37 weeks of gestation acted as controls.

METHODS

Data on resource use, estimated from a National Health Service (NHS) and personal social services perspective, and separately from a societal perspective, were collected between birth and 24 months corrected age (or death), and valued in pounds sterling, at 2010-11 prices. Descriptive statistics and multivariable analyses were used to estimate the relationship between gestational age at birth and economic costs.

MAIN OUTCOME MEASURES

Cumulative resource use and economic costs over the first two years of life.

RESULTS

Of all eligible births, 1146 (83%) preterm and 1258 (79%) term infants were recruited. Mean (standard error) total societal costs from birth to 24 months were £12 037 (£1114) and £5823 (£1232) for children born moderately preterm (32(+0) -33(+6)  weeks of gestation) and late preterm (34(+0) -36(+6)  weeks of gestation), respectively, compared with £2056 (£132) for children born at term. The mean societal cost difference between moderate and late preterm and term infants was £4657 (bootstrap 95% confidence interval, 95% CI £2513-6803; P < 0.001). Multivariable regressions revealed that, after controlling for clinical and sociodemographic characteristics, moderate and late preterm birth increased societal costs by £7583 (£874) and £1963 (£337), respectively, compared with birth at full term.

CONCLUSIONS

Moderate and late preterm birth is associated with significantly increased economic costs over the first 2 years of life. Our economic estimates can be used to inform budgetary and service planning by clinical decision-makers, and economic evaluations of interventions aimed at preventing moderate and late preterm birth or alleviating its adverse consequences.

TWEETABLE ABSTRACT

Moderate and late preterm birth is associated with increased economic costs over the first 2 years of life.

Observational study of children admitted to United Kingdom and Republic of Ireland Paediatric Intensive Care Units after out-of-hospital cardiac arrest

AIMS

To estimate the prevalence of children admitted after out-of-hospital cardiac arrest (OHCA) to UK and Republic of Ireland (RoI) Paediatric Intensive Care Units (PICUs) and factors associated with mortality to inform future clinical trial feasibility.

METHOD

Observational study using a prospectively collected dataset of the Paediatric Intensive Care Audit Network (PICANet) of 33 UK and RoI PICUs (January 2003 to June 2010). Cases (0 to <16 years), with documented OHCA surviving to PICU admission and requiring mechanical ventilation were included. Main outcomes were prevalence for admission and death within PICU. Factors associated with mortality were examined with multiple logistic regression analysis.

RESULTS

827 of 111,170 admissions (0.73%; 95% CI [0.48 to 0.98%]) were identified as children admitted following OHCA. PICU mortality for OHCA was 50.5% (418/827). Recruitment into an adequately sized clinical trial would not be feasible with the current prevalence rate. Characteristics at PICU admission associated with increased risk of death included; bilateral unreactive pupils, genetically inherited condition, inter-hospital transfer to PICU, requirement for vasoactive drugs and greater base deficit. Factors associated with reduced risk of death were submersion or a respiratory aetiology and pre-existing respiratory or cardiac conditions.

CONCLUSIONS

Less than 120 children a year are admitted to PICUs in the UK and RoI after OHCA, limiting options for conducting UK intervention trials. The risk factors associated with mortality identified in this study will allow risk stratification in future studies.

Experiences with maternal and perinatal death reviews in the UK--the MBRRACE-UK programme

Established in 1952, the programme of surveillance and Confidential Enquiries into Maternal Deaths in the UK is the longest running such programme worldwide. Although more recently instituted, surveillance and confidential enquiries into perinatal deaths are also now well established nationally. Recent changes to funding and commissioning of the Enquiries have enabled both a reinvigoration of the processes and improvements to the methodology with an increased frequency of future reporting. Close engagement with stakeholders and a regulator requirement for doctors to participate have both supported the impetus for involvement of all professionals leading to greater potential for improved quality of care for women and babies.

The effects of designation and volume of neonatal care on mortality and morbidity outcomes of very preterm infants in England: retrospective population-based cohort study

OBJECTIVE

To examine the effects of designation and volume of neonatal care at the hospital of birth on mortality and morbidity outcomes in very preterm infants in a managed clinical network setting.

DESIGN

A retrospective, population-based analysis of operational clinical data using adjusted logistic regression and instrumental variables (IV) analyses.

SETTING

165 National Health Service neonatal units in England contributing data to the National Neonatal Research Database at the Neonatal Data Analysis Unit and participating in the Neonatal Economic, Staffing and Clinical Outcomes Project.

PARTICIPANTS

20 554 infants born at <33 weeks completed gestation (17 995 born at 27-32 weeks; 2559 born at <27 weeks), admitted to neonatal care and either discharged or died, over the period 1 January 2009-31 December 2011.

INTERVENTION

Tertiary designation or high-volume neonatal care at the hospital of birth.

OUTCOMES

Neonatal mortality, any in-hospital mortality, surgery for necrotising enterocolitis, surgery for retinopathy of prematurity, bronchopulmonary dysplasia and postmenstrual age at discharge.

RESULTS

Infants born at <33 weeks gestation and admitted to a high-volume neonatal unit at the hospital of birth were at reduced odds of neonatal mortality (IV regression odds ratio (OR) 0.70, 95% CI 0.53 to 0.92) and any in-hospital mortality (IV regression OR 0.68, 95% CI 0.54 to 0.85). The effect of volume on any in-hospital mortality was most acute among infants born at <27 weeks gestation (IV regression OR 0.51, 95% CI 0.33 to 0.79). A negative association between tertiary-level unit designation and mortality was also observed with adjusted logistic regression for infants born at <27 weeks gestation.

CONCLUSIONS

High-volume neonatal care provided at the hospital of birth may protect against in-hospital mortality in very preterm infants. Future developments of neonatal services should promote delivery of very preterm infants at hospitals with high-volume neonatal units.

Perinatal outcomes for extremely preterm babies in relation to place of birth in England: the EPICure 2 study

BACKGROUND

Expertise and resources may be important determinants of outcome for extremely preterm babies. We evaluated the effect of place of birth and perinatal transfer on survival and neonatal morbidity within a prospective cohort of births between 22 and 26 weeks of gestation in England during 2006.

METHODS

We studied the whole population of 2460 births where the fetus was alive at the admission of the mother to hospital for delivery. Outcomes to discharge were compared between level 3 (most intensive) and level 2 maternity services, with and without transfers, and by activity level of level 3 neonatal unit; ORs were adjusted for gestation at birth and birthweight for gestation (adjusted ORs (aOR)).

FINDINGS

Of this national birth cohort, 56% were born in maternity services with level 3 and 34% with level 2 neonatal units; 10% were born in a setting without ongoing intensive care facilities (level 1). When compared with level 2 settings, risk of death in level 3 services was reduced (aOR 0.73 (95% CI 0.59 to 0.90)), but the proportion surviving without neonatal morbidity was similar (aOR 1.27 (0.93 to 1.74)). Analysis by intended hospital of birth confirmed reduced mortality in level 3 services. Following antenatal transfer into a level 3 setting, there were fewer intrapartum or labour ward deaths, and overall mortality was higher for those remaining in level 2 services (aOR 1.44 (1.09 to 1.90)). Among level 3 services, those with higher activity had fewer deaths overall (aOR 0.68 (0.52 to 0.89)).

INTERPRETATION

Despite national policy, only 56% of births between 22 and 26 weeks of gestation occurred in maternity services with a level 3 neonatal facility. Survival was significantly enhanced following birth in level 3 services, particularly those with high activity; this was not at the cost of increased neonatal morbidity.

Contemporary management and outcomes for infants born with oesophageal atresia

Background

Reports on the management and outcome of rare conditions, such as oesophageal atresia, are frequently limited to case series reporting single-centre experience over many years. The aim of this study was to identify all infants born with oesophageal atresia in the UK and Ireland to describe current clinical practice and outcomes.

Methods

This was a prospective multicentre cohort study of all infants born with oesophageal atresia and/or tracheo-oesophageal fistula in 2008–2009 in the UK and Ireland to record current clinical management and early outcomes.

Results

A total of 151 infants admitted to 28 paediatric surgical units were identified. Some aspects of perioperative management were universal, including oesophageal decompression, operative technique and the use of transanastomotic tubes. However, there were a number of areas where clinical practice varied considerably, including the routine use of perioperative chest drains, postoperative contrast studies and antireflux medication, with each of these being employed in 30–50 per cent of patients. There was a trend towards routine postoperative ventilation.

Conclusion

The prospective methodology used in this study can help identify practices that all surgeons employ and also those that few surgeons use. Areas of clinical equipoise can be recognized and avenues for further research identified.

An investigation into the reporting and management of late terminations of pregnancy (between 22 +0 and 26 +6 weeks of gestation) within NHS Hospitals in England in 2006: the EPICure preterm cohort study

OBJECTIVE

To review all late terminations of pregnancy, between 22(+0) and 26(+6) weeks of gestation, collected as part of the EPICure2 study.

DESIGN

Prospective cohort study.

SETTING

All National Health Service (NHS) hospitals providing perinatal services for extremely preterm infants.

POPULATION

All births between 22(+0) and 26(+6) weeks of gestation in England during 2006.

METHODS

Data were collected for the defined cohort of births, including terminations of pregnancy, by designated unit staff using a standardised questionnaire. Rigorous validation processes were established to ensure comprehensive data collection. Gestational age was validated using a hierarchical classification of scan dates, certain date of last menstrual period and working gestation. Data for terminations of pregnancy (TOPs) were categorised into two groups, terminations for fetal abnormality and for maternal or fetal compromise, and were analysed in terms of their reporting, management and outcomes.

MAIN OUTCOME MEASURES

Classification, rate of feticide and outcome following TOP.

RESULTS

Of 3782 births between 22(+0) and 26(+6) weeks of gestation, 647 (17.1%) were TOPs; of these 584 (90.3%) were for fetal abnormality and 63 (9.7%) for maternal or fetal compromise. Feticide was carried out in 489 of 584 (83.7%) TOPs for fetal abnormality, and in 38 of 63 (60.3%) of the TOPs for maternal or fetal compromise. Live births resulted following 2.2% TOPs for fetal abnormality and 4.8% TOPs for maternal or fetal compromise.

CONCLUSION

Terminations of pregnancy represent a relatively large proportion of very preterm births. Fetal abnormalities are the main cause for these terminations, and most include feticide. Better screening strategies are required to avoid the need for late terminations of pregnancy for fetal abnormalities.

Schizencephaly prevalence, prenatal diagnosis and clues to etiology: a register-based study

OBJECTIVES

To establish the prevalence and antenatal diagnosis of schizencephaly in the UK.

METHODS

Data on schizencephaly were extracted from six regional congenital anomaly registers.

RESULTS

Thirty-eight cases of schizencephaly were identified in 2 567 165 livebirths and stillbirths, giving a total prevalence of 1.48/100 000 births (95% CI, 1.01-1.95). Eighteen (47% (95% CI, 31-63%)) of the 38 cases were identified antenatally. No affected fetus had an abnormal karyotype identified. A high proportion of cases of schizencephaly occurred in younger mothers: 63% were aged 24 years or less, significantly higher (P < 0.0001) than the corresponding proportion (26%) of mothers in England and Wales. The majority of cases were not identified until after 22 weeks of pregnancy. Additional anomalies associated with vascular disruption sequences were found in eight cases which had septo-optic dysplasia or absent septum pellucidum, one of which also had gastroschisis.

CONCLUSIONS

Schizencephaly occurs more frequently in the fetuses of younger mothers. It is often associated with septo-optic dysplasia, suggesting that the two conditions may share a common origin, arising as a result of destructive processes that cause changes in the brain which only become apparent on ultrasound in the second half of pregnancy.

Neonatal intensive care outcomes and resource utilisation of infants born <26 weeks in the former Trent region: 2001-2003 compared with 1991-1993

OBJECTIVES

To provide survival data and rates of severe disability at 2 years of corrected age in infants born prior to 26 weeks' gestation in 2001-2003 and to compare these outcomes with an earlier cohort from 1991 to 1993.

DESIGN

Population-based prospective cohort study.

SETTING

Former Trent region of UK covering a population of approximately five million and around 55 000 births per annum.

PARTICIPANTS

The authors identified a 3-year cohort of infants born before 26 weeks' gestation between 1 January 2001 and 31 December 2003 from The Neonatal Survey (TNS). Questionnaires based on the Oxford minimum dataset were completed.

MAIN OUTCOME MEASURES

Survival, service use and disability levels were compared between the 2001- 2003 cohort and the cohort from 1991 to 1993.

RESULTS

In 2001-2003, 0%, 18% and 35% of live born babies were alive at 2 years without any evidence of severe disability at 23, 24 and 25 weeks' gestation, respectively. Overall, of those children admitted to neonatal care, the proportion with no evidence of severe disability at 2 years corrected age improved from 14.5% in 1991-1993 to 26.5% in 2001-2003. There was an increase in the proportion of children with at least one severe disability, out of total admissions to neonatal unit (8% vs 17%) and of those assessed at 2 years (35% vs 39%).

CONCLUSIONS

This study has shown an improvement in survival to discharge in babies admitted for neonatal care. However, this improved survival has been associated with an increase in the proportion of children with at least one severe disability at a corrected age of 2 years.

Deprivation, ethnicity and prematurity in infant respiratory failure in PICU in the UK

AIM

To describe the epidemiology of infants admitted to Paediatric Intensive Care (PIC) with acute respiratory failure including bronchiolitis.

METHODS

Data from all consecutive admissions from 2004 to 2007 in all 29 designated Paediatric Intensive Care Units (PICUs) in England and Wales were collected. Admission rates, risk-adjusted mortality, length of stay, ventilation status, preterm birth, deprivation and ethnicity were studied.

RESULTS

A total of 4641 infants under 1 year of age had an unplanned admission to PIC with acute respiratory failure (ARF), an admission rate of 1.80 per 1000 infants per year. There was a reduced rate of admission with bronchiolitis in South Asian children admitted to PICU, which is not explained by case-mix. Children born preterm had a higher rate of admission and longer stay, but a similar low mortality. Risk-adjusted mortality was higher in South Asian infants and the highest in those with ARF (OR 1.76, 95% CI 1.20-2.57) compared with the rest of the PICU population.

CONCLUSION

Acute respiratory failure in infants causes most of the seasonal variation in unplanned admission to intensive care. Socioeconomic deprivation and prematurity are additional risk factors for admission. Fewer South Asian infants are admitted to PICU with a diagnosis of bronchiolitis, but risk-adjusted mortality is higher in South Asian infants overall.

Estimates of length of neonatal stay for very premature babies in the UK

OBJECTIVE

To describe simple estimates of likely duration of stay for very premature babies born in the UK and discharged home.

DESIGN

Statistical modelling of data from thirty neonatal units in a geographically defined region of the UK.

PARTICIPANTS

All babies born at 23 to 32 completed weeks of gestation in 2005, 2006 and 2007 who were discharged home with the expectation that they would survive.

MAIN OUTCOME MEASURE

Total duration of stay in the neonatal service.

RESULTS

5528 babies were initially identified. 558 (10.1%) who died or who did not follow a normal care pathway were excluded. In a further 27, data were either missing or inadequate, leaving a study population of 4702 babies. As expected, gestation and birthweight exhibited strong influence on length of stay. Of the other variables tested, initial reason for admission (need for early respiratory support) showed the most consistent association. These factors were combined to produce predictive tables. The predictive performance of the tables was found to fit the data well for various groups, with the exception of multiple births who tended to have longer stays. However, when tested against individual units, much greater variation was seen independent of unit size and case mix.

CONCLUSION

The prediction tables should permit parents to make sensible estimates about the duration of their baby's stay in the neonatal service; however, there appear to be important differences between units. The variation noted in length of stay between otherwise similar units merits further investigation.

Predicting neonatal mortality among very preterm infants: a comparison of three versions of the CRIB score

OBJECTIVE

To validate Clinical Risk Index for Babies (CRIB) and CRIB II mortality prediction scores in a UK population of infants born at </=32 weeks' gestation, and investigate CRIB II calculated without admission temperature.

METHODS

Infants born at 22-32 weeks' gestation to mothers resident in a UK region in 2005-2006 admitted for neonatal care were identified. Predictive probabilities for mortality were calculated using CRIB, CRIB II and CRIB II without admission temperature (CRIB II((-T))) using published algorithms and after recalibration. Predictive performance was investigated overall and for groups defined by gestation and admission temperature and summarised by area under receiver-operating curve, Cox's regression, Brier scores and Spiegelhalter's z-scores.

RESULTS

3268 infants were included: 317 (9.7%) died before discharge. Using published algorithms each score showed excellent discrimination (area under the curve = 0.92). The total number of deaths was predicted well for CRIB (324.4) but for both versions of CRIB II the number of deaths was underpredicted (255.2 and 216.6). All scores performed poorly for subgroups. After recalibration CRIB II displayed excellent predictive characteristics overall (Spiegelhalter's z-score p = 0.52) and in the gestation groups (p = 0.44 and 0.57) but not for the temperature groups (p = 0.026 and 0.97). CRIB II((-T)) displayed excellent predictive characteristics for all groups: overall p = 0.53; gestation groups p = 0.64 and 0.42; temperature groups p = 0.42 and 0.66.

CONCLUSIONS

The published algorithm for CRIB II was poorly calibrated but simple linear recalibration provided good results. The CRIB II score without admission temperature showed good predictive characteristics once recalibrated and this version of the score should be used when benchmarking mortality in neonatal intensive care units.

Rates of very preterm birth in Europe and neonatal mortality rates

OBJECTIVE

To estimate the influence of variation in the rate of very preterm delivery on the reported rate of neonatal death in 10 European regions.

DESIGN

Comparison of 10 separate geographically defined European populations, from nine European countries, over a 1-year period (7 months in one region).

PARTICIPANTS

All births that occurred between 22(+0) and 31(+6) weeks of gestation in 2003.

MAIN OUTCOME MEASURE

Neonatal death rate adjusted for rate of delivery at this gestation.

RESULTS

Rate of delivery of all births at 22(+0)-31(+6) weeks of gestation and live births only were calculated for each region. Two regions had significantly higher rates of very preterm delivery per 1000 births: Trent UK (16.8, 95% CI 15.7 to 17.9) and Northern UK (17.1, 95% CI 15.6 to 18.6); group mean 13.2 (95% CI 12.9 to 13.5). Four regions had rates significantly below the group average: Portugal North (10.7, 95% CI 9.6 to 11.8), Eastern and Central Netherlands (10.6, 95% CI 9.7 to 11.6), Eastern Denmark (11.2, 95% CI 10.1 to 12.4) and Lazio in Italy (11.0, 95% CI 10.1 to 11.9). Similar trends were seen in live birth data. Published rates of neonatal death for each region were then adjusted by applying (a) a standardised rate of very preterm delivery and (b) the existing death rate for babies born at this gestation in the individual region. This produced much greater homogeneity in terms of neonatal mortality.

CONCLUSIONS

Variation in the rate of very preterm delivery has a major influence on reported neonatal death rates.

Investigating the variations in survival rates for very preterm infants in 10 European regions: the MOSAIC birth cohort

OBJECTIVE

To investigate the variation in the survival rate and the mortality rates for very preterm infants across Europe.

DESIGN

A prospective birth cohort of very preterm infants for 10 geographically defined European regions during 2003, followed to discharge home from hospital.

PARTICIPANTS

All deliveries from 22 + 0 to 31 + 6 weeks' gestation.

MAIN OUTCOME MEASURE

All outcomes of pregnancy by gestational age group, including termination of pregnancy for congenital anomalies and other reasons, antepartum stillbirth, intrapartum stillbirth, labour ward death, death after admission to a neonatal intensive care unit (NICU) and survival to discharge.

RESULTS

Overall the proportion of this very preterm cohort who survived to discharge from neonatal care was 89.5%, varying from 93.2% to 74.8% across the regions. Less than 2% of infants <24 weeks' gestation and approximately half of the infants from 24 to 27 weeks' gestation survived to discharge home from the NICU. However large variations were seen in the timing of the deaths by region. Among all fetuses alive at onset of labour of 24-27 weeks' gestation, between 84.0% and 98.9% were born alive and between 64.6% and 97.8% were admitted to the NICU. For babies <24 weeks' gestation, between 0% and 79.6% of babies alive at onset of labour were admitted to neonatal intensive care.

CONCLUSIONS

There are wide variations in the survival rates to discharge from neonatal intensive care for very preterm deliveries and in the timing of death across the MOSAIC regions. In order to directly compare international statistics for mortality in very preterm infants, data collection needs to be standardised. We believe that the standard point of comparison should be using all those infants alive at the onset of labour as the denominator for comparisons of mortality rates for very preterm infants analysing the cohort by gestational age band.

Epidemiology of critically ill children in England and Wales: incidence, mortality, deprivation and ethnicity

OBJECTIVE

The purpose of this work was to investigate the incidence rate for admission and mortality of children receiving paediatric intensive care in relation to socioeconomic status and ethnicity in England and Wales.

DESIGN

National cohort of sequential hospital admissions.

SETTING

Twenty nine paediatric intensive care units in England and Wales.

PARTICIPANTS

All children aged under 16 years admitted to paediatric intensive care in the 4 years 2004-2007.

MAIN OUTCOME MEASURES

Incidence rates for admission and odds ratios (OR) for risk-adjusted mortality by an area based measure of deprivation (Townsend score) and ethnic group (south Asian vs non-south Asian determined using two-name analysis algorithms).

RESULTS

The incidence for south Asian children was higher than that of non-south Asian children (138 vs 95/100,000, incidence rate ratio 1.36, 95% CI 1.32 to 1.40). The age-sex standardised incidence for children admitted to paediatric intensive care ranged from 69/100,000 in the least deprived fifth of the population to 124/100,000 in the most deprived fifth. The risk-adjusted OR for mortality for south Asian children was 1.36 (95% CI 1.18 to 1.57) overall, rising to 2.40 (95% CI 1.40 to 4.10) in the least deprived fifth of the population when a statistical interaction term for deprivation was included.

CONCLUSIONS

In England and Wales, the admission rate to paediatric intensive care is higher for children from more deprived areas and 36% higher for children from the south Asian population. Risk-adjusted mortality increases in south Asian children as deprivation decreases.

Geographically based investigation of the influence of very-preterm births on routine mortality statistics from the UK and Australia

BACKGROUND

Comparisons of national perinatal and neonatal mortality often neglect the underlying causes.

OBJECTIVE

To assess effects of very-preterm births in the UK and Australia.

SETTING

Two geographically defined populations: the former Trent Health Region of the UK and New South Wales (NSW)/the Australian Capital Territory (ACT), Australia.

METHOD

All births 22(+0) to 31(+6) weeks in 2000, 2001 and 2002 were identified by established surveys of perinatal care. Rates of birth and death were compared.

RESULTS

The population of NSW/ACT was 35% higher and there were 66% more births than in Trent (273 495 vs 164 824). The proportion of liveborn infants between 22 and 31 weeks gestation was about 25% higher in Trent (NSW/ACT 2945, rate per 1000 live births 10.82 (95% CI 10.43 to 11.22); Trent 2208, rate per 1000 live births 13.47 (95% CI 12.92 to 14.05)). The proportion of these infants admitted to a neonatal unit was also higher in Trent (91.2% vs 94.4%; OR 1.63 (95% CI 1.30 to 2.05)). Unadjusted mortality in infants admitted to a neonatal unit was similar: NSW/ACT 332/2686 (12.4%); Trent 284/2085 (13.6%); unadjusted OR 1.12 (95% CI 0.94 to 1.33; p = 0.21).

CONCLUSIONS

The higher rates of very premature birth and more ready admission to neonatal intensive care for infants in the UK may help to explain why perinatal and neonatal mortality are higher there than in Australia. Efforts to understand why the rate of premature birth in the UK is so high should be a national priority.

Antenatal umbilical Doppler abnormalities: an independent risk factor for early onset neonatal necrotizing enterocolitis in premature infants

BACKGROUND

Necrotizing enterocolitis (NEC) is the most common gastrointestinal (GI) emergency seen in neonatal units. Many factors have been considered as potentially important aetiologically, including gut ischaemia, sepsis and feeding. However, evidence remains equivocal.

OBJECTIVE

This study investigated whether preterm babies born to mothers with abnormal antenatal umbilical Dopplers (absent or reversed end diastolic flow--AREDF), that is exposed to antenatal gut ischaemia, are at an identical risk of developing NEC early in life, compared to babies born to mothers with normal Dopplers.

METHODS

All preterm (<or=32+6 week gestation) babies with no congenital anomaly, born to mothers resident in the county of Leicestershire in United Kingdom in 2001 and 2002 were identified using the Trent Neonatal Survey (TNS). Clinical data including the presence and severity of any NEC were extracted from the notes.

RESULTS

Two hundred forty-three preterm babies who met the criteria were identified during the period. Babies in whom umbilical Dopplers were not available and babies that died in the first 48 h were excluded. Complete data was thus available for 206 of these babies. A strong relation between AREDF and subsequent development of NEC was noted in these babies (OR: 5.88, 95% CI: 2.41 to 14.34, p<0.0001). This association still held after adjustment for gestational age at birth (OR: 7.64, 95% CI: 2.96 to 19.70, p<0.0001) and after adjustment for birthweight for gestational age z-score (OR: 6.72, 95% CI: 2.23 to 20.25, p=0.0007).

CONCLUSIONS

This study, based on a neonatal cohort, indicates that AREDF is an important independent risk factor for the production of NEC.

Socioeconomic inequalities in very preterm birth rates

AIMS

To investigate the extent of socioeconomic inequalities in the incidence of very preterm birth over the past decade.

METHODS

Ecological study of all 549 618 births in the former Trent health region, UK, from 1 January 1994 to 31 December 2003. All singleton births of 22(+0) to 32(+6) weeks gestation (7 185 births) were identified from population surveys of neonatal services and stillbirths. Poisson regression was used to calculate incidence of very preterm birth (22-32 weeks) and extremely preterm birth (22-28 weeks) by year of birth and decile of deprivation (child poverty section of the Index of Multiple Deprivation).

RESULTS

Incidence of very preterm singleton birth rose from 11.9 per 1000 births in 1994 to 13.7 per 1000 births in 2003. Those from the most deprived decile were at nearly twice the risk of very preterm birth compared with those from the least deprived decile, with 16.4 per 1000 births in the most deprived decile compared with 8.5 per 1000 births in the least deprived decile (incidence rate ratio 1.94; 95% CI (1.73 to 2.17)). This deprivation gap remained unchanged throughout the 10-year period. The magnitude of socio-economic inequalities was the same for extremely preterm births (22-28 weeks incidence rate ratio 1.94; 95% CI (1.62 to 2.32)).

CONCLUSIONS

This large, unique dataset of very preterm births shows wide socio-economic inequalities that persist over time. These findings are likely to have consequences on the burden of long-term morbidity. Our research can assist future healthcare planning, the monitoring of socio-economic inequalities and the targeting of interventions in order to reduce this persistent deprivation gap.

Respiratory outcome in late childhood after neonatal continuous negative pressure ventilation

BACKGROUND

The outcome in late childhood for children entered into a randomised trial of continuous negative extrathoracic pressure (CNEP) versus standard respiratory management for the treatment of neonatal respiratory distress was studied. In the original trial, there were advantages in the duration of oxygen and the prevalence of chronic lung disease for those assigned to receive CNEP.

AIM

To determine whether the above differences had persisted into childhood.

METHODS

Outpatient evaluation of children by a paediatrician using Spirometry (Vitalograph Spirometer 2120, Ennis, Ireland) and MicroRint (Micro Medical, Rochester, Kent, UK) techniques independently of the original trial. Parents completed questionnaires about their child's respiratory history and social-demographic information.

RESULTS

133 (65%) survivors were evaluated at 9.6-14.9 years of age. The group examined were representative of the original cohort and no significant baseline differences were observed between children evaluated who had been allocated to CNEP or standard treatments. We compared Rint (before and after bronchodilator) and forced expiratory flow, volume and vital capacity between the two study groups; none were significant. Children in the standard group had received paediatric intensive care more often (p = 0.19) and were more likely to be receiving inhaled drugs for asthma (p = 0.19; all not significant).

CONCLUSIONS

No important differences were found at follow-up in late childhood in respiratory outcomes for children treated with neonatal CNEP or standard treatment. Caution should be exercised, as the original trial was not powered to show these differences, but there seems to be no long-term detriment in respiratory outcomes for children treated with CNEP in the neonatal period.

Neuropsychological and educational problems at school age associated with neonatal encephalopathy

BACKGROUND

Adverse cognitive and educational outcomes are often ascribed to perinatal hypoxia without good evidence.

OBJECTIVE

To investigate neurocognitive and behavioural outcomes after neonatal encephalopathy.

METHODS

Sixty five children with neonatal encephalopathy, identified using the Trent Neonatal Survey database for 1992-1994, were followed up at the age of 7 years. They were examined at school, with a classmate for those in mainstream school, by a paediatrician and a psychologist. Neonatal encephalopathy was graded as moderate or severe using published definitions.

FINDINGS

Fifteen children had major disability, all with cerebral palsy; eight were in special school with severe cognitive impairment (IQ<55). Disability was present in 6% of the moderate and 42% of the severe encephalopathy group. Of the 50 children without motor disability, cognitive scores were lowest in the severe group (mean IQ difference from peers -11.3 points (95% confidence interval (CI) -19.0 to -3.6) and with similar scores for the moderate group compared with classmates (mean difference -1.7 points (95% CI -7.3 to +3.9). Neuropsychological testing showed similar findings in all domains. In particular, memory and attention/executive functions were impaired in the severe group. Despite relatively small differences in performance of the moderate group, special educational needs were identified more often in both encephalopathy groups, associated with lower achievement on national curriculum attainment targets.

INTERPRETATION

After neonatal encephalopathy, subtle cognitive impairments are found in the absence of neuromotor impairment. Subtle impairments are found more commonly after a more severe clinical course. Studies of brain protection strategies require long term follow up to study effects on cognitive outcome.

The potential impact on costs and staffing of introducing clinical networks and British Association of Perinatal Medicine standards to the delivery of neonatal care

OBJECTIVE

To produce models to estimate the impact of introducing clinical networks and the 2001 BAPM standards to the delivery of neonatal care.

DESIGN

Prospective observational study using a geographically defined population and data collected by questionnaire on staffing levels and cot availability.

SETTING

Trent Health Region UK.

SUBJECTS

All infants born to Trent resident mothers at or before 32 weeks gestation between 1 January 1998 and 31 December 1999. Staffing numbers and cot availability for neonatal care in 2001.

METHODS

A modelling exercise was carried out using information for all neonatal admissions for Trent resident infants. Three models were investigated: (a). the current care provision; (b). a network where three lead centres provided the intensive care for the region and the remaining units provided either high dependency or special care alone; (c). a network where six lead centres provided the intensive care for the region and the remaining units provided either high dependency or special care alone. Overall costings, staffing levels, and cot requirements were calculated for each model. Data on staffing levels and cot availability were used to calculate current care provision costings.

RESULTS

The current cost of running the service is approximately pound 33.35 million, although a proportion of nursing posts are currently unfilled. Estimates for the introduction of a three centre model meeting BAPM 2001 standards range from pound 37.31 to pound 43.40 million. Equivalent figures for the six centre model were: pound 36.32 to pound 42.62 million. Approximately 370 and 230 babies a year would be involved in transfer in the three and six centre models respectively. This is in contrast with 374 and 368 urgent transfers that actually took place in 1998 and 1999 respectively.

CONCLUSION

The costs associated with the introduction of managed clinical networks and meeting BAPM standards of care are not excessive, especially when considered against the likely implementation timetable of perhaps 7-10 years. Attracting and retaining sufficient staff will pose the major challenge.

Congenital cystic adenomatoid malformation: accuracy of prenatal diagnosis, prevalence and outcome in a general population

OBJECTIVES

Most available data regarding accuracy of prenatal diagnosis, prevalence and outcome of congenital cystic adenomatoid malformation (CCAM) are derived largely from tertiary referral centres and may not reflect general population rates. We aimed to describe the accuracy of prenatal diagnosis, ascertain the population prevalence and post-natal outcome for cases of suspected CCAM.

METHODS

Retrospective collection of prenatal and paediatric data for cases of suspected CCAM notified to the Trent Congenital Anomalies Register 1997 to 2001.

RESULTS

Thirty-seven cases of CCAM were suspected prenatally. Twenty-one cases were confirmed post-natally as having a CCAM (positive predictive value 57%). Eighteen of the 21 cases were delivered at term as live births, 15 of which have undergone successful surgery to date. Thirteen of the 37 cases had apparently resolved by delivery. Three further cases were subsequently found to be cases of lung sequestration or lobar emphysema. Five cases of CCAM were detected after delivery (sensitivity of prenatal detection 81%). The population prevalence at delivery was 9.0 per 1,00,000 total births. Five confirmed cases of CCAM developed hydrops, three required in utero intervention and delivered as live births at term, one was terminated and one died in utero. The overall mortality in the confirmed cases of CCAM was 23% of which the majority were terminations of pregnancy.

CONCLUSIONS

Problems of diagnostic accuracy and apparent resolution of CCAM render counselling difficult, although our data suggest that the prognosis is better than others have reported. Confirmation of the diagnosis in the neonatal period is vital in order to obtain the true population prevalence figures and to interpret outcome data.

Trisomy 13 and trisomy 18 in a defined population: epidemiological, genetic and prenatal observations

OBJECTIVES

To establish precise incidence figures for trisomy 13 and trisomy 18 in the former Trent region, to identify current prenatal diagnostic practice, and to assess the potential impact of the introduction of recently devised prenatal diagnostic practices.

METHODS

An audit of all cases of trisomy 13 and trisomy 18 ascertained through the records of the Trent Congenital Anomalies Register and the Trent Regional Cytogenetic Laboratories.

RESULTS

Forty-four cases of trisomy 13 and 88 cases of trisomy 18 were ascertained. Advanced maternal age effects were observed. Of all cases, 64% were first detected through chromosomal analysis initiated because of abnormalities noted on fetal anomaly scanning in the second trimester, whereas only 3% of cases were detected through the serum-screening programme currently offered for Down syndrome. In 11% of cases, the diagnosis was first suspected after birth. Twelve percent of couples chose to continue pregnancy following chromosomal confirmation of a suspected diagnosis.

CONCLUSION

The introduction of a highly sensitive prenatal diagnostic screening programme would have a major impact on the timing and proportions of all trisomy 13 and 18 cases diagnosed in pregnancy as gauged by current practice. It is important that health professionals involved in prenatal counselling be aware that, as with Down syndrome and anencephaly, around 12% of prospective parents of a child with trisomy 13 or 18 choose to continue rather than terminate the pregnancy.

Extreme prematurity in the UK and Denmark: population differences in viability

BACKGROUND

Previous studies comparing different models of neonatal intensive care have generally not been population based. The objective of this study was to compare the perinatal services of two total populations.

METHODS

Observational study based on two geographically defined populations: the whole of Demark (some centralisation of neonatal intensive care but most delivered locally by small perinatal centres-48 in total) and the Trent Health Region of the UK (no formal centralisation however deliveries almost all focussed on 16 major hospitals with > 90% of the intensive care provided by 13 hospitals). Information was recorded about the course of every liveborn infant < 28 weeks gestation and or < 1000g birth weight and > or = 21 weeks gestation in 1994 and 1995.

RESULTS

Despite having a smaller population the number of liveborn children meeting the study criteria was significantly higher in Trent (Demark 461 (3.3 per 1000 births, 95% confidence interval (CI) 3.0 to 3.6); Trent 572 (4.9 per 1000 births, 95% CI 4.5 to 5.3)). In Denmark 91.1% of these infants were admitted for intensive care and 85.5% in Trent. Despite significantly more Trent infants being exposed to antenatal steroids their outcome was worse (median Clinical Risk Index for Babies (CRIB) score 7 v 4; proportion receiving ventilation 87.6% v 40.0%; survival to discharge (uncorrected for disease severity) 42.3% v 35.0%).

CONCLUSION

The population characteristics of Trent seemed to produce a higher prematurity rate compared to Denmark. These infants as a group appeared sicker and, despite more intensive care delivered by a more specialised service, outcomes were worse.

A confidential enquiry into cases of neonatal encephalopathy

OBJECTIVES

To assess the quality of care and timing of possible asphyxial events for infants with neonatal encephalopathy; to compare the quality of care findings with those relating to the deaths from the Confidential Enquiry into Stillbirths and Deaths in Infancy (CESDI); and to assess whether the confidential enquiry method is a useful clinical governance tool for investigating morbidity.

DESIGN

Independent, anonymised, multidisciplinary case reviews.

SETTING

Trent Health Region, UK.

PATIENTS

All cases of grade II and III neonatal encephalopathy born in 1997, excluding those due to congenital malformation, inborn error of metabolism, or infection. All CESDI deaths thought to have resulted from intrapartum asphyxia in 1996 and 1997.

MAIN MEASURES

Quality of care provided, timing of possible asphyxial episodes, and the source and timing of episodes of suboptimal care.

RESULTS

Significant or major episodes of suboptimal care were identified for 64% of the encephalopathy cases and 75% of the deaths. An average of 2.8 and 2.5 episodes of suboptimal care were identified for the deaths and encephalopathy cases respectively. Over 90% of episodes involved the care provided by health professionals. Results were fed directly back to the units concerned on request and changes in practice have been reported.

CONCLUSIONS

The findings were very similar for the encephalopathy cases and the deaths. We have demonstrated that with minor adaptations the CESDI process can be applied to serious cases of morbidity. However, explicit quality standards, control data, and a more formal mechanism for the implementation of findings would strengthen the confidential enquiry process as part of clinical governance.

Measuring later health status of high risk infants: randomised comparison of two simple methods of data collection

OBJECTIVE

To test two methods of providing low cost information on the later health status of survivors of neonatal intensive care.

DESIGN

Cluster randomised comparison.

SETTING

Nine hospitals distributed across two UK health regions. Each hospital was randomised to use one of two methods of follow up.

PARTICIPANTS

All infants born

METHOD

Families were recruited at the time of discharge. In one method of follow up families were asked to complete a questionnaire about their child's health at the age of 2 years (corrected for gestation). In the other method the children's progress was followed by clerks in the local community child health department by using sources of routine information.

RESULTS

236 infants were recruited to each method of follow up. Questionnaires were returned by 214 parents (91%; 95% confidence interval 84% to 97%) and 223 clerks (95%; 86% to 100%). Completed questionnaires were returned by 201 parents (85%; 76% to 94%) and 158 clerks (67%; 43% to 91%). Most parents found the forms easy to complete, but some had trouble understanding the concept of "corrected age" and hence when to return the form. Community clerks often had to rely on information that was out of date and difficult to interpret.

CONCLUSION

Neither questionnaires from parents nor routinely collected health data are adequate methods of providing complete follow up data on children who were born preterm and required neonatal intensive care, though both methods show potential.

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Key Words Collapse

MESH Headings

• Community Health Services/methods
• Costs and Cost Analysis
• Data Collection/economics
• Data Collection/methods
• Follow-Up Studies
• Health Status Indicators
• Humans
• Infant, Newborn
• Infant, Premature
• Intensive Care, Neonatal
• Parents
• Prognosis
• Reproducibility of Results
• Surveys and Questionnaires

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Grants Collapse

Affiliation(s)

D Field University of Leicester Medical School, Leicester, UK.
E S Draper
M J Gompels
C Green
A Johnson
D Shortland
M Blair
B Manktelow
C R Lamming
C Law

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Factors affecting the incidence of chronic lung disease of prematurity in 1987, 1992, and 1997

OBJECTIVE

To determine changes in the incidence of chronic lung disease of prematurity between 1987, 1992, and 1997.

METHODS

Observational study based on data derived from a geographically defined population: Trent Health Region, United Kingdom. Three time periods were compared: 1 February 1987 to 31 January 1988 (referred to as 1987); 1 April 1992 to 31 March 1993 (referred to as 1992); 1997. All infants of < or = 32 completed weeks gestation born to Trent resident mothers within the study periods and admitted to a neonatal unit were included. Rates of chronic lung disease were determined using two definitions: (a) infants who remained dependent on active respiratory support or increased oxygen at 28 days of age; (b) infants who remained dependent on active respiratory support or increased oxygen at a corrected age of 36 weeks gestation.

RESULTS

Between 1987 and 1992 there was a fall in the birth rate, but a significant increase was noted in the number of babies of < or = 32 weeks gestation admitted to a neonatal unit. There was no significant change in survival when the two groups of infants were directly compared. However, mean gestation and birth weight fell. Adjusting for this change showed a significant improvement in survival (28 day survival: odds ratio (OR) = 1.69; 95% confidence interval (95% CI) = 1.23 to 2.33. Survival to 36 week corrected gestation: OR = 1.45; 95% CI = 1.06 to 1.98). These changes were accompanied by a large increase in the incidence of chronic lung disease even after allowing for the change in population characteristics (28 day definition: OR = 2.20; 95% CI = 1.47 to 3.30. 36 week definition: OR = 3.04; 95% CI = 1.91 to 4.83). Between 1992 and 1997 a different pattern emerged. There was a further increase in the number of babies admitted for neonatal care at </= 32 weeks gestation despite a continuing fall in overall birth rate. Survival, using both raw data and data corrected for changes in gestation and birth weight, improved significantly in 1997 (adjusted data: 28 day survival: OR = 1.72 (95% CI = 1.22 to 2.38); survival to 36 week corrected gestation: OR = 1.90 (95% CI = 1.36 to 2.64)). Rates of chronic lung disease showed no significant change between 1992 and 1997 despite improved survival (adjusted data: 28 day definition: OR = 0.72 (95% CI = 0.50 to 1.03); 36 week definition: OR = 0.88 (95% CI = 0.61 to 1.26).

CONCLUSIONS

Current high rates of chronic lung disease are the result of policies to offer neonatal intensive care more widely to the most immature infants. Recent improvements in survival have been achieved without further increases in the risk of infants developing chronic lung disease.

Chronic lung disease and survival in 4 tertiary neonatal units

AIM

To compare mortality and respiratory morbidity in preterm infants born at 4 United Kingdom centers during 1994 and 1995.

METHOD

Collection of CRIB scores, respiratory parameters and mortality rates from unit databases.

RESULTS

Mortality in center A was 27% (actual number of deaths 36/135), in center B was 30% (39/130), in center C was 28% (51/182), in center D was 39% (60/156). The rate of chronic lung disease (36 week definition) in center A was 16%, in center B was 12%, in center C was 13%, in center D was 15%. The predicted number of deaths by CRIB scores in center A was 54 (95% confidence intervals 45-63), in center B was 33 (25-41), in center C was 53 (43-63), in center D was 46 (37-56).

CONCLUSION

Center A had a lower than predicted mortality. Center D had a higher than predicted mortality. There is an urgent need for a national neonatal database to allow comparison between center and to identify reasons for variation in outcomes.

Severe retinopathy of prematurity and its association with different rates of survival in infants of less than 1251 g birth weight

BACKGROUND

There is controversy over whether improved survival of preterm infants has resulted in a higher incidence of severe (grade 3 or greater) retinopathy of prematurity (ROP).

AIM

To compare survival rates and rates of > or = stage 3 ROP-that is, with a high risk of sequelae-in preterm infants in five English cities where, anecdotally, the incidence of ROP is reported to show considerable variation.

METHODS

All infants of birth weight < 1500 g and or gestational age < 32 weeks, born in 1994 in one of the cities or transferred in within 48 hours, were studied. The populations were adjusted for case mix variation using CRIB (clinical risk index for babies, a disease severity scoring system). The incidence of severe ROP, the actual death rate, and that adjusted for disease severity were determined.

RESULTS

The rate of severe ROP per 1000 births was higher in city 1 than in all the other cities. This increase in comparison with city 2 and city 4 was significant (city 1, 167 (95% confidence interval (CI) 96 to 260); city 2, 24 (6 to 59); city 4, 16 (1 to 84)). A significant difference was not seen between city 1 and cities 3 (23 (1 to 120)) and 5 (74 (21 to 79)). The relative risk of developing severe ROP in city 1 compared with all the other cities was 5.5 (2.5 to 11.9). The actual death rate per 1000 births in city 1 was significantly lower than that predicted by modelling death against CRIB score (city 1: actual 270; predicted 385 (95% CI 339 to 431)). In contrast, the other cities had actual death rates as predicted, or worse than predicted, by CRIB.

INTERPRETATION

A significantly higher incidence of severe ROP was identified in one of the five cities studied. Variation in survival rates among high risk infants may explain this observation.

Prediction of survival for preterm births by weight and gestational age: retrospective population based study

OBJECTIVE

To produce current data on survival of preterm infants.

DESIGN

Retrospective population based study.

SETTING

Trent health region.

SUBJECTS

All European and Asian live births, stillbirths, and late fetal losses from 22 to 32 weeks' gestation, excluding those with major congenital malformations, in women resident in the Trent health region between 1 January 1994 and 31 December 1997.

MAIN OUTCOME MEASURES

Birth weight and gestational age specific survival for both European and Asian infants (a) known to be alive at the onset of labour, and (b) admitted for neonatal care.

RESULTS

738 deaths occurred in 3760 infants born between 22 and 32 weeks' gestation during the study period, giving an overall survival rate of 80.4%. The survival rate for the 3489 (92.8%) infants admitted for neonatal care was 86.6%. For European infants known to be alive at the onset of labour, significant variations in gestation specific survival by birth weight emerged from 24 weeks' gestation: survival ranged from 9% (95% confidence interval 7% to 13%) for infants of birth weight 250-499 g to 21% (16% to 28%) for those of 1000-1249 g. At 27 weeks' gestation, survival ranged from 55% (49% to 61%) for infants of birth weight 500-749 g (below the 10th centile) to 80% (76% to 85%) for those of 1250-1499 g. Infants who were large for dates (>/=27 weeks' gestation) had a slightly reduced, but not significant, predicted survival. Similar survival rates were observed for Asian infants. The odds ratio for the survival of infants from a multiple birth compared with singleton infants was 1.4 (1.1 to 1.8). Survival graphs for infants admitted for neonatal care are presented by sex.

CONCLUSION

Easy to use birth weight and gestational age specific predicted survival graphs for preterm infants facilitate decision making for clinicians and parents. It is important that these graphs are representative, are produced for a geographically defined population, and are not biased towards the outcomes of particular centres. Such graphs, produced in two stages, allow for the changing pattern of survival of infants from the start of the intrapartum period to immediately after admission for neonatal care.

Assessment of separate contributions to perinatal mortality of infertility history and treatment: a case-control analysis

BACKGROUND

Few studies have described the perinatal risks associated with infertility, other than for infertility treated by in-vitro fertilisation or gamete intrafallopian transfer. The aim of this analysis was to estimate the risks of perinatal death associated with treated and untreated infertility.

METHODS

A population-based case-control study of perinatal deaths was carried out in Leicestershire Health District over the period 1990-94, during which 60,922 babies were delivered. Of these, 567 perinatal deaths were associated with 542 women. 972 mothers were randomly selected as controls. Medical, obstetric, and social data were collected for cases and controls from the medical notes and interviews with the women. The relative risks of perinatal death associated with treated and untreated infertility before the index pregnancy were estimated as odds ratios by means of unconditional logistic regression analysis.

FINDINGS

65 (10%) of cases and 34 (3.5%) of the controls had infertility before the index pregnancy. History of infertility in the index pregnancy, irrespective of treatment, increased the risk of perinatal death (odds ratio 2.9 [95% CI 1.8-4.5]). The population attributable risk fraction for perinatal death related to infertility was 6.2% (3.4-9.0). 45 (54%) of the deaths, even in the untreated group, were associated with immaturity. Compared with women without infertility, women with untreated infertility were at increased risk of perinatal death (3.3 [1.6-6.8]). The risk of perinatal death associated with multiple births did not explain this finding. Similarly, treated infertility also increased the risk of perinatal death (2.7 [1.5-4.7]); the risks associated with multiple births explained some, but not all, of this excess. In Leicestershire, the overall underlying risk of a mother experiencing at least one perinatal death over the study was 9.0 per 1000 women. For women who experience infertility, this risk increases by about 18 per 1000 (6-30).

INTERPRETATION

Counselling for women before any form of infertility treatment should include discussion of the risks of perinatal death. Our results would benefit from confirmation. However, we advocate that at antenatal booking a history of infertility, irrespective of treatment, should be sought, because these women have a significantly increased risk of perinatal death, particularly associated with prematurity.

Health status of a population of infants born before 26 weeks gestation derived from routine data collected between 21 and 27 months post-delivery

This retrospective study was designed: (a) to determine the extent to which routine data sources in the UK can provide data relating to the later health status of selected groups of infants; and (b) to use such an approach to describe the outcome of a geographically defined population of infants born before 26 weeks gestation. All infants of less than 26 weeks gestation admitted for neonatal intensive care during the period 1/1/91 and 31/12/93 whose mother's address at the time of birth was within the boundaries of the Trent Health Region were included. Health status was assessed against a previously described simple scheme and using information from existing sources only. During the 3-year period 249 infants of less than 26 weeks gestation were admitted for intensive care. Of these 66 (26.5%) survived to be discharged from the neonatal service. A further seven infants died before the age of 2 years. Of the remaining 59 four were lost to follow up (three could not be traced; one was living abroad). Of the 55 infants reviewed, 36 demonstrated no features, pre-defined in the classification scheme, of severe disability. However, only 30 children appeared to be considered entirely normal.

CONCLUSION

Infants born before 26 weeks gestation and admitted for neonatal intensive care had, approximately, a 12% chance of normal survival to 2 years. A slightly smaller proportion of infants survived with significant disability. Existing routine data sources could be adapted to provide useful public health information about the outcome of 'high risk' groups of infants.

Survival and place of delivery following preterm birth: 1994-96

AIM

To compare the survival of premature infants, adjusted for disease severity, in different types of neonatal intensive care setting.

METHODS

A prospective observational study in the Trent Health Region was carried out of all infants born to resident mothers at or before 32 weeks of gestation between 1 January 1994 to 31 December 1996 inclusive. The 16 neonatal units in Trent were subdivided into five relatively large units which regularly took outside referrals and 11 smaller units which provided intensive care for a variable proportion (sometimes nearly 100%) of their local population. Data regarding obstetric management, neonatal care, and outcome were collected by independent neonatal nurses who visited the units on a regular basis. Survival rates were compared with an expected rate calculated using the Clinical Risk Index for Babies (CRIB). For either setting to be abnormally good or bad actual deaths had to exceed the 95% confidence interval of the CRIB estimate.

RESULTS

Actual survival rates for infants < or = 32 weeks gestation and for the group of babies < or = 28 weeks gestation fell within the 95% confidence interval of the rate predicted by CRIB for both the larger referral units and the smaller district units. Similarly, compared with the CRIB prediction, infants transferred in utero or postnatally were not adversely affected in terms of the number who died.

CONCLUSION

Previous results from this geographical population, showing that survival of babies < or = 28 weeks gestation was better when their care was provided by referral units, are no longer sustained. Significant changes to the neonatal services over time make the current results plausible. However, the new structure poses potential threats to the teaching, training, and research base of the neonatal service as a whole.

The pregnant smoker: a preliminary investigation of the social and psychological influences

BACKGROUND

Smoking during pregnancy is an important challenge to public health. An understanding of the psychological and sociological bases of maternal smoking is essential to the development of effective smoking cessation interventions. The aim of this study was to explore the psychosocial factors that underpin maternal smoking.

METHODS

Semi-structured interviews were conducted with 200 antenatal attenders at Leicester Royal Infirmary, NHS Trust, UK.

RESULTS

Twenty-nine per cent were smokers, 22 per cent ex-smokers and 49 per cent were never smokers. Around half of the ex-smokers (49 per cent) had reportedly given up smoking during their current pregnancy. Around a third (29.5 per cent) of the ex-smokers had experienced previous problems associated with maternal smoking, including spontaneous abortion, cot death and premature birth. Of the current smokers, 69 per cent claimed that they would like to give up smoking; indeed, 59 per cent had tried to stop smoking. Emotional factors were important in maintaining smoking for two-thirds of the smokers. Significantly more of the smokers (75 per cent) had partners who smoked compared with the never-smoking women (30 per cent; p < 0.001). There was no difference in the level of knowledge about the dangers of maternal smoking between smokers, ex-smokers and never smokers.

CONCLUSIONS

Pregnant smokers are as aware of the health risks as non-smokers. Effective intervention strategies need to focus not only on the pregnant woman's smoking status but also offer help to partners, close family members and friends. Interventions need to address the social and psychological factors that maintain maternal smoking.

Impact of extremely immature infants on neonatal services

The impact of very immature infants on neonatal services was examined within the United Kingdom. The Trent Health Region was used as a geographically defined population. Data were obtained on all infants weighing less than 1501 g at birth and all infants born before 32 weeks gestation between 1991-93. Information relating to length of stay, duration of ventilation, and survival was documented. Only one of 49 infants born before 24 weeks gestation survived. However, 75% of this group were ventilated. Most of the remaining infants died before 48 hours of age. A similar pattern was also seen in infants of 24 and 25 weeks gestation. Infants under 24 weeks gestation comprised 1.5% of all ventilated infants and consumed 2.14% of the total neonatal ventilator days for the region. It is concluded that the United Kingdom operates a conservative policy towards infants born before 24 weeks gestation and as a result resources expended on them are limited.