Abstract
A voluntary survey set up by local clinicians has documented all lethal abnormality in a geographically defined area of northern England where there were 361,037 registered births between 1982 and 1990, and monitored the incidence of all significant physical abnormality since January 1984. The survey aims to maintain a register of all pregnancies where an abnormality is suspected before birth, and those where an abnormality is only identified after birth, together with a record of how the diagnosis was established. Information on management and outcome a year after birth is also collected. Nearly half the total decline in perinatal mortality in the region between 1982 and 1990 is accounted for by an increase in the antenatal recognition of lethal abnormality, isolated hydrocephalus, or a neural tube defect and subsequent termination of pregnancy. Although the reporting of many non-lethal conditions was incomplete during the pilot study in 1984, it has become progressively more complete since then. The number of cases confirmed postnatally varied little between units between 1985-9, but audit showed that the proportion recognised antenatally varied fivefold for reasons unconnected with unit size or the amount of antenatal ultrasound work done. For a number of serious conditions more than 10% of all antenatal diagnoses were completely wrong. Survey data are, for the first time, making it possible to monitor the accuracy of the ultrasound-based screening and diagnostic services for identifying specific fetal abnormalities. They are also providing clinicians with an invaluable confidential database of a whole region's collective experience of dealing with complex fetal abnormality.