Linking a European cohort of children born with congenital anomalies to vital statistics and mortality records: A EUROlinkCAT study

EUROCAT is a European network of population-based congenital anomaly (CA) registries. Twenty-one registries agreed to participate in the EUROlinkCAT study to determine if reliable information on the survival of children born with a major CA between 1995 and 2014 can be obtained through linkage to national vital statistics or mortality records. Live birth children with a CA could be linked using personal identifiers to either their national vital statistics (including birth records, death records, hospital records) or to mortality records only, depending on the data available within each region. In total, 18 of 21 registries with data on 192,862 children born with congenital anomalies participated in the study. One registry was unable to get ethical approval to participate and linkage was not possible for two registries due to local reasons. Eleven registries linked to vital statistics and seven registries linked to mortality records only; one of the latter only had identification numbers for 78% of cases, hence it was excluded from further analysis. For registries linking to vital statistics: six linked over 95% of their cases for all years and five were unable to link at least 85% of all live born CA children in the earlier years of the study. No estimate of linkage success could be calculated for registries linking to mortality records. Irrespective of linkage method, deaths that occurred during the first week of life were over three times less likely to be linked compared to deaths occurring after the first week of life. Linkage to vital statistics can provide accurate estimates of survival of children with CAs in some European countries. Bias arises when linkage is not successful, as early neonatal deaths were less likely to be linked. Linkage to mortality records only cannot be recommended, as linkage quality, and hence bias, cannot be assessed.

EUROCAT: an update on its functions and activities

This paper provides an outline of the development and growth of EUROCAT, the European network of congenital anomaly registers. In recent years the network has been through a period of transition and change. The Central Register of data has transferred from the Ulster University to the EU Joint-Research-Centre, Ispra, Italy.The benefits of combining data from across Europe, from different populations and countries are described by the uses to which these data can be put. These uses include:. surveillance of anomalies at a local, regional or pan-European level. pharmacovigilance. registration of rare diseasesNew studies and projects are underway, including EUROlinkCAT (a Horizon 2020 funded data-linkage project), promising a fruitful future in further research of congenital anomalies.

Risk of congenital anomalies after exposure to asthma medication in the first trimester of pregnancy - a cohort linkage study

Objective

To examine the effect of maternal exposure to asthma medications on the risk of congenital anomalies.

Design

Meta‐analysis of aggregated data from three cohort studies.

Setting

Linkage between healthcare databases and EUROCAT congenital anomaly registries.

Population

519 242 pregnancies in Norway (2004–2010), Wales (2000–2010) and Funen, Denmark (2000–2010).

Methods

Exposure defined as having at least one prescription for asthma medications issued (Wales) or dispensed (Norway, Denmark) from 91 days before to 91 days after the pregnancy start date. Odds ratios (ORs) were estimated separately for each register and combined in meta‐analyses.

Main outcome measures

ORs for all congenital anomalies and specific congenital anomalies.

Results

Overall exposure prevalence was 3.76%. For exposure to asthma medication in general, the adjusted OR (adjOR) for a major congenital anomaly was 1.21 (99% CI 1.09–1.34) after adjustment for maternal age and socioeconomic position. The OR of anal atresia was significantly increased in pregnancies exposed to inhaled corticosteroids (3.40; 99% CI 1.15–10.04). For severe congenital heart defects, an increased OR (1.97; 1.12–3.49) was associated with exposure to combination treatment with inhaled corticosteroids and long‐acting beta‐2‐agonists. Associations with renal dysplasia were driven by exposure to short‐acting beta‐2‐agonists (2.37; 1.20–4.67).

Conclusion

The increased risk of congenital anomalies for women taking asthma medication is small with little confounding by maternal age or socioeconomic status. The study confirmed the association of inhaled corticosteroids with anal atresia found in earlier research and found potential new associations with combination treatment. The potential new associations should be interpreted with caution due to the large number of comparisons undertaken.

Tweetable abstract

This cohort study found a small increased risk of congenital anomalies for women taking asthma medication.

This cohort study found a small increased risk of congenital anomalies for women taking asthma medication.

Prevalence and risk of Down syndrome in monozygotic and dizygotic multiple pregnancies in Europe: implications for prenatal screening

OBJECTIVE

To determine risk of Down syndrome (DS) in multiple relative to singleton pregnancies, and compare prenatal diagnosis rates and pregnancy outcome.

DESIGN

Population-based prevalence study based on EUROCAT congenital anomaly registries.

SETTING

Eight European countries.

POPULATION

14.8 million births 1990-2009; 2.89% multiple births.

METHODS

DS cases included livebirths, fetal deaths from 20 weeks, and terminations of pregnancy for fetal anomaly (TOPFA). Zygosity is inferred from like/unlike sex for birth denominators, and from concordance for DS cases.

MAIN OUTCOME MEASURES

Relative risk (RR) of DS per fetus/baby from multiple versus singleton pregnancies and per pregnancy in monozygotic/dizygotic versus singleton pregnancies. Proportion of prenatally diagnosed and pregnancy outcome.

STATISTICAL ANALYSIS

Poisson and logistic regression stratified for maternal age, country and time.

RESULTS

Overall, the adjusted (adj) RR of DS for fetus/babies from multiple versus singleton pregnancies was 0.58 (95% CI 0.53-0.62), similar for all maternal ages except for mothers over 44, for whom it was considerably lower. In 8.7% of twin pairs affected by DS, both co-twins were diagnosed with the condition. The adjRR of DS for monozygotic versus singleton pregnancies was 0.34 (95% CI 0.25-0.44) and for dizygotic versus singleton pregnancies 1.34 (95% CI 1.23-1.46). DS fetuses from multiple births were less likely to be prenatally diagnosed than singletons (adjOR 0.62 [95% CI 0.50-0.78]) and following diagnosis less likely to be TOPFA (adjOR 0.40 [95% CI 0.27-0.59]).

CONCLUSIONS

The risk of DS per fetus/baby is lower in multiple than singleton pregnancies. These estimates can be used for genetic counselling and prenatal screening.

Trends in the prevalence, risk and pregnancy outcome of multiple births with congenital anomaly: a registry-based study in 14 European countries 1984-2007

OBJECTIVE

To assess the public health consequences of the rise in multiple births with respect to congenital anomalies.

DESIGN

Descriptive epidemiological analysis of data from population-based congenital anomaly registries.

SETTING

Fourteen European countries.

POPULATION

A total of 5.4 million births 1984-2007, of which 3% were multiple births.

METHODS

Cases of congenital anomaly included live births, fetal deaths from 20 weeks of gestation and terminations of pregnancy for fetal anomaly.

MAIN OUTCOME MEASURES

Prevalence rates per 10,000 births and relative risk of congenital anomaly in multiple versus singleton births (1984-2007); proportion prenatally diagnosed, proportion by pregnancy outcome (2000-07). Proportion of pairs where both co-twins were cases.

RESULTS

Prevalence of congenital anomalies from multiple births increased from 5.9 (1984-87) to 10.7 per 10,000 births (2004-07). Relative risk of nonchromosomal anomaly in multiple births was 1.35 (95% CI 1.31-1.39), increasing over time, and of chromosomal anomalies was 0.72 (95% CI 0.65-0.80), decreasing over time. In 11.4% of affected twin pairs both babies had congenital anomalies (2000-07). The prenatal diagnosis rate was similar for multiple and singleton pregnancies. Cases from multiple pregnancies were less likely to be terminations of pregnancy for fetal anomaly, odds ratio 0.41 (95% CI 0.35-0.48) and more likely to be stillbirths and neonatal deaths.

CONCLUSIONS

The increase in babies who are both from a multiple pregnancy and affected by a congenital anomaly has implications for prenatal and postnatal service provision. The contribution of assisted reproductive technologies to the increase in risk needs further research. The deficit of chromosomal anomalies among multiple births has relevance for prenatal risk counselling.

Survey of prenatal screening policies in Europe for structural malformations and chromosome anomalies, and their impact on detection and termination rates for neural tube defects and Down's syndrome

Objective

To ‘map’ the current (2004) state of prenatal screening in Europe.

Design

(i) Survey of country policies and (ii) analysis of data from EUROCAT (European Surveillance of Congenital Anomalies) population-based congenital anomaly registers.

Setting

Europe.

Population

Survey of prenatal screening policies in 18 countries and 1.13 million births in 12 countries in 2002–04.

Methods

(i) Questionnaire on national screening policies and termination of pregnancy for fetal anomaly (TOPFA) laws in 2004. (ii) Analysis of data on prenatal detection and termination for Down's syndrome and neural tube defects (NTDs) using the EUROCAT database.

Main outcome measures

Existence of national prenatal screening policies, legal gestation limit for TOPFA, prenatal detection and termination rates for Down's syndrome and NTD.

Results

Ten of the 18 countries had a national country-wide policy for Down's syndrome screening and 14/18 for structural anomaly scanning. Sixty-eight percent of Down's syndrome cases (range 0–95%) were detected prenatally, of which 88% resulted in termination of pregnancy. Eighty-eight percent (range 25–94%) of cases of NTD were prenatally detected, of which 88% resulted in termination. Countries with a first-trimester screening policy had the highest proportion of prenatally diagnosed Down's syndrome cases. Countries with no official national Down's syndrome screening or structural anomaly scan policy had the lowest proportion of prenatally diagnosed Down's syndrome and NTD cases. Six of the 18 countries had a legal gestational age limit for TOPFA, and in two countries, termination of pregnancy was illegal at any gestation.

Conclusions

There are large differences in screening policies between countries in Europe. These, as well as organisational and cultural factors, are associated with wide country variation in prenatal detection rates for Down's syndrome and NTD.

Please cite this paper as: Boyd P, DeVigan C, Khoshnood B, Loane M, Garne E, Dolk H, and the EUROCAT working group. Survey of prenatal screening policies in Europe for structural malformations and chromosome anomalies, and their impact on detection and termination rates for neural tube defects and Down's syndrome. BJOG 2008;115:689–696.

Agreement between Cochrane Neonatal reviews and clinical practice guidelines for newborns in Denmark: a cross-sectional study

OBJECTIVE

To assess agreement between Cochrane Neonatal Group reviews and clinical practice guidelines in Denmark.

DESIGN

Retrospective analysis of clinical guidelines for newborn infants.

MATERIALS

All Cochrane neonatal reviews and Danish clinical guidelines for newborn infants.

MAIN OUTCOME MEASURES

The recommendations from the Cochrane reviews and local clinical guidelines were compared and classified as being in agreement, in partial agreement or in disagreement. Authors of guidelines were asked whether Cochrane reviews had been considered during guideline development and reasons for any disagreements. Heterogeneity among departments was assessed.

RESULTS

173 interventions evaluated in Cochrane neonatal reviews were included. All 17 Danish neonatal departments agreed to participate, but only 14 (82%) delivered data. Agreement between reviews and guidelines was observed for a median of 132 interventions (76%) (range 129-134), partial agreement was observed for 31 interventions (18%) (range 29-33), and disagreement was observed for 10 interventions (6%) (range 8-13) (kappa = 0.56, range 0.53-0.59). Most of the latter 10 interventions were not recommended in the reviews but were recommended in the guidelines. There were numerous reasons for disagreement, the most common being usage of evidence with higher bias risks than randomised trials in guidelines development. Overall, Cochrane reviews were rarely (10%) used during guideline development. For nine guideline topics (5%) there was diversity among the Danish departments' recommendations.

CONCLUSIONS

There is good agreement between Cochrane reviews and neonatal guidelines in Denmark. However, Cochrane reviews were rarely used for guideline development. Heterogeneity among guidelines produced by the various neonatal departments seems moderate.

Trends and geographic inequalities in the prevalence of Down syndrome in Europe, 1980-1999

BACKGROUND

EUROCAT is a network of population-based registries for the epidemiologic surveillance of congenital anomalies covering approximately one quarter of births in the European Union. Down syndrome constitutes approximately 8% of cases of registered congenital anomaly in Europe, with over 7000 affected pregnancies in the 15 current member states of the European Union each year. In this paper, we aim to examine trends in the live birth prevalence of Down syndrome in Europe in the light of trends in maternal age and in prenatal diagnosis.

METHODS

Descriptive analysis of data from 24 EUROCAT registries, covering 8.3 million births 1980-99. Cases include live births, stillbirths and terminations of pregnancy following prenatal diagnosis.

RESULTS

Since 1980, the proportion of births to mothers of 35 years of age and over has risen quite dramatically from 8 to 14% for the European Union as a whole, with steeper rises in some regions. By 1995-1999, the proportion of "older" mothers varied between regions from 10% to 25%, and the total prevalence (including terminations of pregnancy) of Down syndrome varied from 1 to 3 per 1000 births. Some European regions have shown a more than twofold increase in total prevalence of Down syndrome since 1980. The proportion of cases of Down syndrome which were prenatally diagnosed followed by termination of pregnancy in 1995-1999 varied from 0% in the three regions of Ireland and Malta where termination of pregnancy is illegal, to less than 50% in 14 further regions, to 77% in Paris. The extent to which terminations of pregnancy were concen trated among older mothers varied between regions. The live birth prevalence has since 1980 increasingly diverged from the rising total prevalence, in some areas remaining approximately stable, in others decreasing over time.

CONCLUSION

The rise in average maternal age in Europe has brought with it an increase in the number of pregnancies affected by Down syndrome. The widespread practice of prenatal screening and termination of pregnancy has in most of the regions covered by EUROCAT counteracted the effect of maternal age in its effect on live birth prevalence. Under the joint influences of maternal age and prenatal screening the pattern of geographic inequalities in Down syndrome live birth prevalence in Europe has also been changed.

Prenatal diagnosis of severe structural congenital malformations in Europe

OBJECTIVES

To assess at a population-based level the frequency with which severe structural congenital malformations are detected prenatally in Europe and the gestational age at detection, and to describe regional variation in these indicators.

METHODS

In the period 1995-1999, data were obtained from 17 European population-based registries of congenital malformations (EUROCAT). Included were all live births, fetal deaths and terminations of pregnancy diagnosed with one or more of the following malformations: anencephalus, encephalocele, spina bifida, hydrocephalus, transposition of great arteries, hypoplastic left heart, limb reduction defect, bilateral renal agenesis, diaphragmatic hernia, omphalocele and gastroschisis.

RESULTS

The 17 registries reported 4366 cases diagnosed with the 11 severe structural malformations and of these 2300 were live births (53%), 181 were fetal deaths (4%) and 1863 were terminations of pregnancy (43%); in 22 cases pregnancy outcome was unknown. The overall prenatal detection rate was 64% (range, 25-88% across regions). The proportion of terminations of pregnancy varied between regions from 15% to 59% of all cases. Gestational age at discovery for prenatally diagnosed cases was less than 24 weeks for 68% (range, 36-88%) of cases. There was a significant relationship between high prenatal detection rate and early diagnosis (P < 0.0001). For individual malformations, the prenatal detection rate was highest for anencephalus (469/498, 94%) and lowest for transposition of the great arteries (89/324, 27%). Termination of pregnancy was performed in more than half of the prenatally diagnosed cases, except for those with transposition of the great arteries, diaphragmatic hernia and gastroschisis, in which 30-40% of the pregnancies with a prenatal diagnosis were terminated.

CONCLUSION

European countries currently vary widely in the provision and uptake of prenatal screening and its quality, as well as the "culture" in terms of decision to continue the pregnancy. This inevitably contributes to variation between countries in perinatal and infant mortality and in childhood prevalence and cost to health services of congenital anomalies.

Declining autopsy rates in stillbirths and infant deaths: results from Funen County, Denmark, 1986-96

OBJECTIVE

The aim of this study was to describe the development of the autopsy rate in stillbirths and infant deaths in an 11-year period and evaluate the information gained by performing an autopsy.

METHODS

Included in the study were all stillbirths and infant deaths in Funen County, Denmark, in 1986-96. Data sources were death certificates and autopsy reports.

RESULTS

The study included 273 stillbirths and 351 deaths in infancy. The rates of stillbirth and infant death did not change significantly during the period. The overall autopsy rate for stillbirths was 70% and for infant deaths 57%. There was a significant decline in autopsy rate during the years 1991-96 as compared with 1986-90 for stillbirths, infant deaths and infant deaths excluding sudden infant death syndrome. In stillbirth, the autopsy changed the diagnosis in 9% of the cases. In 22%, the clinical diagnosis was maintained, but additional information was obtained. In infant death, the numbers were 10% and 40%, respectively.

CONCLUSION

In 10% of the autopsies the diagnosis was changed completely, with an impact on genetic counseling as well as on statistical records of causes of death in fetuses and infants. With additional information in 22-40% of the autopsies, the study emphasizes autopsy as a useful investigation.

Gastrointestinal malformations in Funen county, Denmark--epidemiology, associated malformations, surgery and mortality

AIM

To report the epidemiology, associated malformations, morbidity and mortality for the first 5 years of life for infants with gastrointestinal malformations (GIM).

METHODS

Population-based study using data from a registry of congenital malformations (Eurocat) and follow-up data from hospital records. The study included livebirths, fetal deaths with a gestational age of 20 weeks and older and induced abortions after prenatal diagnosis of malformations born during the period 1980 - 1993.

RESULTS

A total of 109 infants/fetuses with 118 GIM were included in the study giving a prevalence of 15.3 (12.6 - 18.5) cases per 10 000 births. Anal atresia was present in seven of the 9 cases with more than one GIM. There were 38 cases (35 %) with associated malformations and/or karyotype anomalies. Thirty-two of the 90 live-born infants died during the first 5 years of life with the majority of deaths during the first week of life. Mortality was significantly increased for infants with associated malformations or karyotype anomalies compared to infants with isolated GIM (p < 0.01). An uneventful surgical course was reported for 74 % of the 58 survivors.

CONCLUSIONS

The prognosis for infants with GIM is highly dependent on the presence of associated malformations or karyotype anomalies. Surgery for GIM can be performed with low mortality. Morbidity is high for a small group of infants, but the majority of survivors have an uncomplicated surgical course.

Congenital diaphragmatic hernia: evaluation of prenatal diagnosis in 20 European regions

OBJECTIVE

To evaluate prenatal diagnosis of congenital diaphragmatic hernia by ultrasound in well-defined European populations.

DESIGN

Data from 20 registries of congenital malformations in 12 European countries were included. The prenatal ultrasound screening programs in the countries ranged from no routine screening to three ultrasound investigations per patient being routinely performed.

RESULTS

There were 187 cases with congenital diaphragmatic hernia, with an overall prenatal detection rate of 59% (110/187). There was considerable variation in prenatal detection rate between regions. There was a significant difference in the detection rate of isolated congenital diaphragmatic hernia (59/116, 51%) compared with congenital diaphragmatic hernia associated with multiple malformations, karyotype anomalies or syndromes (51/71, 72%) (P = 0.01). Termination of pregnancy was performed in 39 cases (21%) of which 14 cases were isolated congenital diaphragmatic hernia. Mean gestational age at discovery was 24.2 weeks (range, 11-38 weeks).

CONCLUSIONS

The overall prenatal detection rate of congenital diaphragmatic hernia is high (59%) but varies significantly between European regions. The gestational age at discovery was greater than 24 weeks in half of the prenatally diagnosed cases.

Chromosomal congenital anomalies and residence near hazardous waste landfill sites

Previous findings of the EUROHAZCON study showed a 33% increase in risk of non-chromosomal anomalies near hazardous waste landfill sites. Here, we studied 245 cases of chromosomal anomalies and 2412 controls who lived near 23 such sites in Europe. After adjustment for confounding by maternal age and socioeconomic status, we noted a higher risk of chromosomal anomalies in people who lived close to sites (0-3 km) than in those who lived further away (3-7 km; odds ratio 1.41, 95% CI 1.00-1.99). Our results suggest an increase in risk of chromosomal anomalies similar to that found for non-chromosomal anomalies.

Different policies on prenatal ultrasound screening programmes and induced abortions explain regional variations in infant mortality with congenital malformations

OBJECTIVE

To compare the impact of induced abortions (IA) on the mortality of infants with congenital malformations in four European regions with different policies on IA and prenatal ultrasound screening for congenital malformations.

METHODS

A registry-based collection of data on congenital malformations in four different countries: Ireland (Dublin), Denmark (Funen County), Austria (Styria), and France (Strasbourg).

RESULTS

The proportion of infant deaths with malformations ranged from 23 to 44% of all infant deaths with the highest proportion in Dublin, where IA is not allowed and prenatal ultrasound screening not performed. There were highly significant differences in the prevalences of IA (p < 0.001), fetal deaths (p < 0.01), and deaths in infants with congenital malformations (p < 0.001) between the four regions. The differences in total mortality with congenital malformations (IA + fetal deaths + infant deaths) between regions decreased, and only Strasbourg differs significantly from the other three regions.

CONCLUSION

Prenatal ultrasound screening programmes have only a minor impact on total mortality with congenital malformations from 2nd trimester of pregnancy to 1 year of age, but seem to change the time of death which may be important for both the parents and the community.

Evaluation of prenatal diagnosis of congenital heart diseases by ultrasound: experience from 20 European registries

OBJECTIVES

To evaluate prenatal diagnosis of congenital heart diseases by ultrasound investigation in well-defined European populations.

DESIGN

Data from 20 registries of congenital malformations in 12 European countries were included. The prenatal ultrasound screening programs in the countries ranged from no routine screening to three ultrasound investigations per patient routinely performed.

RESULTS

There were 2454 cases with congenital heart disease with an overall prenatal detection rate of 25%. Termination of pregnancy was performed in 293 cases (12%). There was considerable variation in prenatal detection rate between regions, with the lowest detection rates being in countries without ultrasound screening (11%) and in Eastern European countries (Croatia, Lithuania and Ukraine; 8%). In Western European countries with ultrasound screening, detection rate ranged from 19-48%. There was a significant difference in prenatal detection rate and proportion of induced abortions between isolated congenital heart disease and congenital heart disease associated with chromosome anomalies, multiple malformations and syndromes (P < 0.0001). There were 1694 cases with isolated congenital heart disease of which 16% were diagnosed prenatally. Malformations affecting the size of the ventricles were detected prenatally in half of the cases.

CONCLUSIONS

Prenatal detection rate of congenital heart disease varies significantly between countries even with the same screening recommendations. The presence of associated malformations significantly increases the prenatal detection rate.

Evaluation of prenatal diagnosis of associated congenital heart diseases by fetal ultrasonographic examination in Europe

Ultrasound scans in the mid trimester of pregnancy are now a routine part of antenatal care in most European countries. With the assistance of Registries of Congenital Anomalies a study was undertaken in Europe. The objective of the study was to evaluate prenatal detection of congenital heart defects (CHD) by routine ultrasonographic examination of the fetus. All congenital malformations suspected prenatally and all congenital malformations, including chromosome anomalies, confirmed at birth were identified from the Congenital Malformation Registers, including 20 registers from the following European countries: Austria, Croatia, Denmark, France, Germany, Italy, Lithuania, Spain, Switzerland, The Netherlands, UK and Ukrainia. These registries follow the same methodology. The study period was 1996-1998, 709 030 births were covered, and 8126 cases with congenital malformations were registered. If more than one cardiac malformation was present the case was coded as complex cardiac malformation. CHD were subdivided into 'isolated' when only a cardiac malformation was present and 'associated' when at least one other major extra cardiac malformation was present. The associated CHD were subdivided into chromosomal, syndromic non-chromosomal and multiple. The study comprised 761 associated CHD including 282 cases with multiple malformations, 375 cases with chromosomal anomalies and 104 cases with non-chromosomal syndromes. The proportion of prenatal diagnosis of associated CHD varied in relation to the ultrasound screening policies from 17.9% in countries without routine screening (The Netherlands and Denmark) to 46.0% in countries with only one routine fetal scan and 55.6% in countries with two or three routine fetal scans. The prenatal detection rate of chromosomal anomalies was 40.3% (151/375 cases). This rate for recognized syndromes and multiply malformed with CHD was 51.9% (54/104 cases) and 48.6% (137/282 cases), respectively; 150/229 Down syndrome (65.8%) were livebirths. Concerning the syndromic cases, the detection rate of deletion 22q11, situs anomalies and VATER association was 44.4%, 64.7% and 46.6%, respectively. In conclusion, the present study shows large regional variations in the prenatal detection rate of CHD with the highest rates in European regions with three screening scans. Prenatal diagnosis of CHD is significantly higher if associated malformations are present. Cardiac defects affecting the size of the ventricles have the highest detection rate. Mean gestational age at discovery was 20-24 weeks for the majority of associated cardiac defects.

Prenatal diagnosis of six major cardiac malformations in Europe--a population based study

AIM

To present data on prenatal diagnosis of six major cardiac malformations in low-risk European populations.

METHODS

Data from 12 Eurocat registries on congenital malformations. All registries have multiple sources of information and use the same methods of data collection and coding. The six cardiac malformations included were hypoplastic left heart, tricuspid atresia, single ventricle, Tetralogy of Fallot, transposition of great arteries and common A-V-canal.

RESULTS

There were significant differences in the proportion of cases diagnosed prenatally, with the highest detection rate in France (91% for single ventricle in Paris) and the lowest detection rate in countries without prenatal ultrasound screening (no cases diagnosed prenatally in the Danish registry area). Prenatal detection rate was significantly higher for the three malformations affecting the size of the ventricles (hypoplastic left heart, tricuspid atresia, single ventricle) compared to the other three malformations (46% versus 24%, p<0.001). Time of diagnosis was late, with only one third diagnosed before 24 weeks of gestation. The risk of fetal death seems to be low.

CONCLUSION

There are significant regional differences in prenatal detection rate of major cardiac malformations in Europe.

Tetralogy of Fallot. A population-based study of epidemiology, associated malformations and survival in western Denmark 1984-1992

The study describes the epidemiology and mortality of tetralogy of Fallot (TOF) in a population-based study in Western Denmark. Ninety-two infants with TOF were born during 1984-1992. Prevalence was 3.01 per 10,000 livebirths. Karyotype anomalies were present in 12 (13%) and extracardiac malformations in 16 (17%) of the infants. Down syndrome, cleft palate, cleft lip and palate and combined skeletal, gastrointestinal and renal lesions (VACTERL association) were prevalent. Twenty-four infants died (26% of total), 13 (54%) of the deaths occurring during the first year of life. Mortality was significantly increased in infants with extracardiac malformations (50% vs 19%, p < 0.05). Eighteen deaths (75% of total deaths) occurred before corrective surgery and 7 of these deaths were sudden. Extracardiac malformation(s) in infants with TOF is a significant risk factor for death. The study stresses the importance of population-based studies for the assessment of mortality from congenital heart malformations. Overall mortality may be very different from mortality related to cardiac surgery.

Risk of congenital anomalies near hazardous-waste landfill sites in Europe: the EUROHAZCON study

BACKGROUND

Waste-disposal sites are a potential hazard to health. This study is a multicentre case-control study of the risk of congenital anomalies associated with residence near hazardous-waste landfill sites in Europe.

METHODS

We used data from seven regional registers of congenital anomalies in five countries. We studied 1089 livebirths, stillbirths, and terminations of pregnancy with non-chromosomal congenital anomalies and 2366 control births without malformation, whose mothers resided within 7 km of a landfill site; 21 sites were included. A zone within 3 km radius of each site was defined as the "proximate zone" of most likely exposure to teratogens.

FINDINGS

Residence within 3 km of a landfill site was associated with a significantly raised risk of congenital anomaly (295 cases/511 controls living 0-3 km from sites, 794/1855 living 3-7 km from sites; combined odds ratio 1.33 [95% CI 1.11-1.59], adjusted for maternal age and socioeconomic status). There was a fairly consistent decrease in risk with distance away from the sites. A significantly raised odds ratio for residence within 3 km of a landfill site was found for neural-tube defects (odds ratio 1.86 [1.24-2.79]), malformations of the cardiac septa (1.49 [1.09-2.04]), and anomalies of great arteries and veins (1.81 [1.02-3.20]). Odds ratios of borderline significance were found for tracheo-oesophageal anomalies (2.25 [0.96-5.26]), hypospadias (1.96 [0.98-3.92]), and gastroschisis (3.19 [0.95-10.77]). There was little evidence of differences in risk between landfill sites but power to detect such differences was low.

INTERPRETATION

This study shows a raised risk of congenital anomaly in babies whose mothers live close to landfill sites that handle hazardous chemical wastes, although there is a need for further investigation of whether the association of raised risk of congenital anomaly and residence near landfill sites is a causal one. Apparent differences between malformation subgroups should be interpreted cautiously.

Heterogeneity of neural tube defects in Europe: the significance of site of defect and presence of other major anomalies in relation to geographic differences in prevalence

In the period 1980-1987, neural tube defects were two to three times more prevalent in populations covered by EUROCAT registries in the United Kingdom and Ireland (UKI) than in Continental Europe and Malta (CEM). 1864 NTD cases in a total population of 580,000 births in UKI and 455 cases in a population of 380,000 births in CEM were analysed to find if there were differences in the ratio of prevalence rates between UKI and CEM according to site of the defect and association with non-central nervous system (CNS) anomalies. The prevalence rate ratio was high for anencephaly with accompanying spina bifida, iniencephaly, and upper spina bifida, and low for encephalocele, lower spina bifida, and anencephaly without other neural tube defects. There was a greater female excess for anencephaly with accompanying spina bifida, iniencephaly, and upper spina bifida than for other defects in both geographic areas. There was a female excess for encephalocele in UKI but a male excess in CEM. Certain sites (anencephaly with accompanying spina bifida, iniencephaly, and encephalocele) were more likely to have accompanying non-CNS anomalies. The prevalence rate ratio of multiply malformed NTD was in general lower than for isolated NTD but showed the same pattern by site. The prevalence rate ratio was high for multiply malformed anencephaly with accompanying spina bifida, iniencephaly, and upper spina bifida. The sex ratio was similar between isolated and multiply malformed cases when site of the defect is taken into account. It is concluded that the geographic prevalence pattern and sex ratio differ according to site of NTD but do not differ substantially according to whether NTD is isolated or associated with non-CNS anomalies.

[Complications of long-term treatment with vitamin K antagonists]

Long-term treatment with vitamin K antagonists (vKA) frequently involves complications. The commonest complication is haemorrhage and cases of serious haemorrhage are stated in the literature to occur with a frequency per 1,000 treatment years of 12-108, of which 2-17 are fatal. The majority of deaths associated with haemorrhage are due to intracranial haemorrhage. Notifications of complications of vKA treatment in Denmark are considerably fewer than might be anticipated from the literature. The stability of anticoagulation treatment decreases with the number of drugs administered simultaneously and numerous drugs and other factors interact with the effect of vKA. A series of examples are reviewed and some known drugs which do not interact are mentioned. Non-haemorrhagic side effects of coumarin derivatives are rare. Anticoagulation treatment during pregnancy is associated with very special problems and must be regarded as a specialist task.

[Wound infection following heart surgery]

Two hundred patients who had been submitted to cardiac surgery were subdivided at random into two groups with removal of the dressings on the first or fifth postoperative day. The risk of wound infection was demonstrated to be identical in the two groups. Early removal of the dressings is therefore recommended.