Children born with congenital anomalies have a higher risk of death than healthy children. New research shows that the later the year of birth of a child with a congenital anomaly, the more likely that child is to survive. A number of factors are contributing to this trend, including medical advances in both treatments and surgical techniques, and the increasing rate of termination of the pregnancies with the worst outlook. The findings are reported in an Article published Online First (www.thelancet.com) and in an upcoming edition of the Lancet, written by researchers from the Institute of Health and Society, Newcastle University, Newcastle-upon-Tyne, UK, led by Dr Judith Rankin.
Congenital anomalies are a leading cause of perinatal and infant mortality. Advances in care have improved the prognosis for some congenital anomaly groups and subtypes, but there remains little knowledge about survival for many others, especially beyond the first year of life. To date, most studies in this area have reported survival in individuals with either Down's syndrome or spina bifida. In this study, the authors estimated survival up to 20 years of age for a range of congenital anomaly groups and subtypes.
Information about children with at least one congenital anomaly, delivered between 1985 and 2003, was obtained from the UK Northern Congenital Abnormality Survey (NorCAS—a long running congenital abnormality register in the north of England). Anomalies were categorised by group (the system affected), subtype (the individual disorder), and syndrome according to European Surveillance of Congenital Anomalies (EUROCAT) guidelines. Local hospital and national mortality records were used to identify the survival status of liveborn children. Survival up to 20 years of age was estimated.
A total of 13 758 cases of congenital anomaly were notified to NorCAS between 1985 and 2003. There were just under 11 000 livebirths, with survival data available in 99% of cases. 20-year survival was 86% in individuals born with at least one congenital anomaly (, 90% for cardiovascular system anomalies, 79% for chromosomal anomalies, 93% for urinary system anomalies, 83% for digestive system anomalies, 98% for orofacial clefts, and 66% for nervous system anomalies. Survival varied between subtypes within the same congenital anomaly group. The proportion of terminations for fetal anomaly increased throughout the study period, from 12•4% in 1985 to 18•3% in 2003.
The authors point out several important medical advances that have improved survival in this population over the years, such as surfactant therapy* and corticosteroid use in respiratory distress syndrome, intrapartum treatment for chorioamnionitis** to prevent neonatal sepsis, and public health campaigns that have lowered the incidence of sudden unexpected death in infancy. More specific to congenital anomalies, there have also been substantial advances in surgical techniques, especially for cardiovascular system anomalies, and in prenatal diagnosis. The authors say: "Aside from increasing the proportion of pregnancies eligible for termination, prenatal diagnosis might also improve outcome in liveborn individuals."
They add: "We found a significant temporal trend in the rate of termination of pregnancy for fetal anomaly, which explained part of the effect of year of birth on survival. Although several mechanisms could explain this association, the most likely is the selective termination of pregnancies with the worst prognoses. This occurrence has already been posited as an important contributor to the reduction in infant mortality in the general population, with increasing rates of termination of pregnancy reducing the number of children being born alive with congenital anomalies."
Survival varied between subtypes within the same group, most notably in anomalies of the nervous, cardiovascular, and urinary systems. The authors say that this finding highlights the importance of presenting survival data for congenital anomalies by subtype because of the significant variation within congenital anomaly groups. They urge researches to report the various subtypes whenever possible. The authors also highlight the immense value of regional congenital anomaly registers, and say this study would not have been possible without the existence of the long-running NorCAS register.
The authors conclude: "We report robust estimates of survival up to 20 years of age for a range of congenital anomaly groups and subtypes, some of which have been infrequently reported previously. This information will be valuable for families, genetic counsellors, and other health-care professionals when a congenital anomaly is detected, and will assist in planning for the future care needs of affected individuals."
In an accompanying Comment, Dr David H Stone, Paediatric Epidemiology and Community Health (PEACH) Unit, University of Glasgow, UK, says: "Birth-defect registries have had a chequered history since their initial proliferation after the thalidomide disaster. They have proved exceptionally useful for aetiological studies, though their potential clinical role has often been neglected. Despite endorsement by England's Chief Medical Officer, these crucial sources of perinatal data face a continuous struggle for funding. The result is that much of the UK and many countries worldwide remain devoid of good-quality data for congenital anomalies on which epidemiological research into prevalence, aetiology, and outcomes depends. The publication of today's findings from the north of England should provide a much-needed boost to the cause of congenital anomaly surveillance."
Dr Judith Rankin, Institute of Health and Society, Newcastle University, Newcastle-upon-Tyne, UK. T) +44 (0) 191 222 5267 E) j.m.rankin@ncl.ac.uk
Dr David H Stone, Paediatric Epidemiology and Community Health (PEACH) Unit, University of Glasgow, UK. T) +44 (0) 7903 613 405 E) d.h.stone@clinmed.gla.ac.uk
For full Article and Comment, see: http://press.thelancet.com/congenital.pdf
Notes to editors:
*surfactant therapy: Surfactant is a substance made in the lungs of healthy newborn babies that helps them breathe more easily. In babies born prematurely they often do not make enough surfactant in the first few hours. Doctors can give artificial surfactant to premature or sick babies through the tube that is used to provide breathing support when they are first born.
**Chorioamnionitis is an inflammation of the fetal membranes (the amnion and the chorion) due to a bacterial infection
Journal
The Lancet