Informe de Vigilancia Epidemiológica de anomalías congénitas en España: Datos registrados por el ECEMC en el período 1980-2009

Abstract

This report is delivered annually by ECEMC (Spanish Collaborative Study of Congenital Malformations), a research programme on congenital anomalies, based on data from its ongoing, hospital-based, case-control registry of newborn infants in Spain. It has surveyed more than 2.7 million births, and studied and gathered data on more than 40,800 consecutive infants with congenital anomalies and a similar number of healthy controls. Present coverage of the registry surpasses 20.4% of total births in Spain. The global frequency of infants with congenital defects has signifi cantly decreased along the time, from 2.22% in the base period (1980-1985), to 0.98% in 2009, mainly as a consequence of the impact of elective termination of pregnancy (eTOP) after the diagnosis of foetal anomalies in a proportion of affected pregnancies. eTOP is legal in Spain since 1985. The global decrease reaches statistically signifi cant levels in many of the participating hospitals and most Spanish Autonomic Regions (see Fig. 1). Extremadura is the only Autonomic Region in which an increase was detected, probably due to methodological issues in the base period and the referral of complicated pregnancies due to congenital defects to other regions, both causing a low frequency; since then, the obstetrical and neonatological assistance have considerably improved, leading to a higher detection of cases born at this region. A group of 33 defects were selected due to their relatively high base frequency and/or the morbidity/mortality associated to them, and the evolution of their frequency along the time was studied. Most of them decreased, and the only increases were observed for heart/great vessels defects and unilateral renal agenesis, possibly due to improving resources for their detection, whether pre or Postnatal. Temporal-spatial analyses of the frequency were performed for a group of 18 defects and many statistically signifi cant decreases were observed in most Spanish Autonomic Regions. There were also some increases: for anotia/microtia, diaphragmatic hernia and gastroschisis in the Balearic Islands. Regarding anotia/microtia, the increase was attributable to the birth of 3 cases in year 2009, without any apparent common denominator among the cases registered, apart from the area of birth, from which a causal relationship could be inferred; nevertheless, the frequency in 2009 does not differ from the global for all the other regions in the same year. The increases for diaphragmatic hernia and gastroschisis were due to the birth of one case presenting with both defects in a multiple congenital anomaly pattern. Some geographical heterogeneity could be detected in 2009 for Down’s syndrome and hypospadias. For Down’s syndrome, the heterogeneity was attributable to the relatively high frequency registered in the Región de Murcia; however,most of the cases were born to mothers aged 35 years or older. Regarding hypospadias, the heterogeneity was due to the relatively high frequency observed in Castilla y León and Principado de Asturias; in both autonomic regions the cases presented the defect isolated, and apparently did not share any other characteristic that could provide clues on some causal agent specifi cally linked to these areas. The ethnic origin of cases and foreign extraction of their parents were also analysed. All the ethnic groups had a risk for congenital anomalies that was higher than for the native white group. The group of foreign parents has increased along the time, and it is more frequent among cases than among controls (thus, a higher risk for congenital defects could be inferred for the group of foreigners). In conclusion, ECEMC has demonstrated to be an effective programme to perform the epidemiological surveillance of congenital anomalies in Spain since its creation in 1976. It has achieved a valuable system “with comprehensive collection that can be used to monitor trends, identify clusters that may require investigation, evaluate the effectiveness of screening and interventions for treatment and prevention, and allow research into the prevention of congenital anomalies”, as recently proposed by Bower et al. [MJA 2010;192(6):300-301]