Prenatal detection rate of congenital anomalies over a period of 30 years: A population-based registry study.

Objective: Prenatal diagnosis of congenital anomalies is extremely important because permits monitoring, in utero treatments and delivery in a setting with the appropriate level of care. The aim of the study was to provide updated data on the prevalence, detection rate (DR) and gestational age at diagnosis of selected severe congenital malformations.

Study Design: Data on 11 isolated malformations (anencephaly, hydrocephaly, encephalocele, spina bifida, transposition of great arteries, hypoplastic left heart, limb reduction defect, bilateral renal agenesis, diaphragmatic hernia, gastroschisis, omphalocele) were extracted from the population-based Registry of Congenital Anomalies of Tuscany. Prenatal DR, gestational age at discovery, rate of termination of pregnancy, prevalence per 10,000 births and prenatal DR trend over 30 years were calculated.

Results: Overall DR was83.2% (79.5-86.5%). DR of specific isolated anomaly was: 98.0% (89.4-99.9%) for anencephaly, 100% (71.5-100%) for encephalocele, 91.4% (81.0-97.1%) for spina bifida, 97.5% (86.9-99.9%) for hydrocephaly; 81.6% (71.0-89.5%) for transposition of the great arteries, 95.9% (86.0-99.5%) for hypoplastic left heart, 53.6% (41.2-65.7%) for limb reduction defects, 100% (69.2-100) for bilateral renal agenesis, 71.4% (57.8-82.7%) for diaphragmatic hernia, 100% (85.2-100%) for gastroschisis, 68% (46.5-85.1%) for omphalocele. There was an overall increase of the DR through decades for the majority of malformations.

Conclusion: Prenatal DR has increased during the last 30 years. The DR depends on the specific type of anomaly with central nervous system anomaliesand bilateral renal agenesis having the highest values and limb defects (53.6 %) the lowest. Nevertheless, the diagnosis of severe malformations is not possible in all cases.