Predictive value and completeness of the registration of congenital abnormalities in three Danish population-based registries.

Aims: The predictive value and completeness of data on congenital abnormalities (CAs) collected in three administrative health registries in the County of North Jutland, Denmark were compared.

Methods: The study included all singleton liveborn infants in the county during the period 1991-94 (n = 24,147). All infants recorded as having a CA in either the Medical Birth Registry (MBR), the Hospital Discharge Registry (HDR), or the National Registry of Congenital Abnormalities (NRCA) were identified, and the recordings in each registry were compared.