The Active Malformations Surveillance Program, Boston in 1972-2012: Methodology and demographic characteristics.

Background: Malformations surveillance programs have been carried out in consecutive populations of newborn infants at single hospitals, as well as in several hospitals in defined populations. A surveillance program begins with the review of the findings recorded by the examining pediatrician in each infant's medical record. The results of diagnostic tests, consultations, and imaging studies are obtained, also, from that infant's medical record. Some malformations surveillance programs identify additional malformations over several months, as the infants have hospitalizations and additional diagnostic testing.

Methods: 289,365 infants (liveborn, stillborn, and fetuses in pregnancies terminated because of anomalies) were surveyed from 1972 to 2012 at an urban maternity center in Boston to identify each infant with one or more malformations. Each mother was interviewed to obtain demographic characteristics, results of prenatal testing, family history, and information about exposures in pregnancies. Specific diagnoses were established by the study geneticists.

Results: 7,020 (2.4%) of the 289,365 infants surveyed had one or more malformations. The etiologies identified included chromosome abnormalities, phenotypes attributed to dominant or recessive autosomal or X-linked mutations, vascular disruption, environmental factors, and complications of twinning.

Conclusion: The surveillance of a large consecutive population of newborn infants, stillbirths, and aborted fetuses can identify with high reliability all infants with one or more malformations. This process of ascertainment of affected newborns can be used to improve genetic counseling, identify "new" phenotypes, and serve as a system for testing new technologies to establish more causes of congenital malformations.