Original articleCongenital hydrocephalus – prevalence, prenatal diagnosis and outcome of pregnancy in four European regions
Introduction
Congenital hydrocephalus is characterized by an abnormal accumulation of cerebrospinal fluid (CSF) in the brain.1 In the fetus and the infant the main clinical sign is enlargement of the head although in some cases with cerebral ventriculomegaly the head circumference is within normal limits. The CSF may be under pressure causing compression and damage to the brain. The reason for the accumulation of the CSF is an imbalance between production and absorption of the CSF. The most common causes of congenital hydrocephalus are obstruction of the cerebral aqueduct flow, Arnold Chiari malformation or Dandy–Walker malformation.2
In fetuses and infants the diagnosis of hydrocephalus is usually made following ultrasound scans. With the increasing number and quality of prenatal ultrasound investigations more cases are now diagnosed antenatally. The first prenatal signs of hydrocephalus may be visible on ultrasound around 18–20 weeks of gestation, the “banana sign” though in some cases the hydrocephalus is only visible later in gestation. Parents face difficult decisions on whether to continue or terminate the pregnancy when the diagnosis is made late in the second trimester and information on prognosis related to scan findings is lacking. For optimal counselling data on pregnancy outcome and childhood outcome in liveborn infants with congenital hydrocephalus are needed.
As congenital hydrocephalus is rare and because hydrocephalus also may be acquired after perinatal events (tumours, cerebral bleeding, CNS infections) publications give outcome data on these groups of infants together,3 or include infants with spina bifida4 or cover a long time period in order to have a reasonable number of cases.5 Further published series only give data on liveborn infants referred for surgery.4, 5, 6
The aim of this study is to give the prevalence of congenital hydrocephalus in four European regions using population-based data from European Surveillance of Congenital Anomalies (EUROCAT) and describe prenatal diagnosis, outcome of pregnancy and mortality for the liveborn infants.
Section snippets
Materials and methods
EUROCAT registries are population-based and the geographically defined populations and methods of case ascertainment of EUROCAT are described elsewhere (http://www.eurocat.ulster.ac.uk/memberreg). The registries are based on multiple sources of information such as hospital records, birth and death certificates and post mortem examinations, and include information about livebirths (LB), fetal deaths (FD) with gestational age (GA) ≥ 20 weeks and terminations of pregnancy (TOPFA) after prenatal
Results
Fig. 1 shows the total number of cases pre- and postnatally diagnosed with outcome of pregnancy and survival.
Discussion
Our study found a prevalence of CH at 4.65 per 10,000 births. Prevalence of CH (as defined in this study) has previously been reported to be 3.7 per 10,000 births in a Northern Region in the UK 1985–19969 and 8.1 per 10,000 births in Strasbourg, France 1979– 1987.10 In the French study a large proportion of cases (29%) were diagnosed in infancy (after 1 week). As the definition of CH is broad without strict criteria for the size of the ventricles, prevalence may differ between studies. In our
Acknowledgements
The National Perinatal Epidemiology Unit Oxford is funded by the Department of Health in England. The views expressed in this paper are those of the authors and do not necessarily reflect the views of the Department of Health.
References (20)
Congenital hydrocephalus
Neurosurg Clin N Am
(2001)- et al.
Longitudinal reference charts for growth of the fetal head, abdomen and femur
Eur J Obstet Gynecol Reprod Biol
(2006) - et al.
Congenital hydronephrosis – prenatal diagnosis and epidemiology in Europe
J Pediatr Urol
(2009) - et al.
Cerebral palsy and congenital malformations
Eur J Paediatr Neurol
(2008) - et al.
Diseases of the nervous system in childhood
(1998) - et al.
Disabilities in children with hydrocephalus – a population-based study of children aged between four and twelve years
Neuropediatrics
(2006) - et al.
Long-term follow-up in 233 patients with congenital hydrocephalus
Childs Nerv Syst
(1995) - et al.
Long-term functional evaluation of congenital hydrocephalus in infants and children
Kurume Med J
(2002) - et al.
The long-term outlook for hydrocephalus in childhood. A ten-year cohort study of 155 patients
Pediatr Neurosurg
(1997) - et al.
Charts of fetal size: 2. Head measurements
Br J Obstet Gynaecol
(1994)