Trends in fetal and infant deaths caused by congenital anomalies.

Understanding the causes that underlie the recent dramatic declines in infant deaths caused by congenital anomalies requires an appreciation of trends in cause-specific infant mortality, and especially trends in gestational age-specific and cause-specific fetal mortality. This article examines temporal changes in gestational age-specific and cause-of-death-specific fetal mortality rates in Canada, congenital anomaly-related infant mortality rates in Canada, England and Wales, and the United States, and cause-of-death-specific infant mortality rates in Canada and the United States. Fetal deaths caused by congenital anomalies at very early gestation (20-25 weeks) have increased dramatically in recent years, while fetal and infant deaths at later gestations have declined. Prenatal diagnosis and selective termination of pregnancies affected by congenital anomalies appears to be the major factor responsible for the accelerated decline in infant deaths. Further declines in overall infant mortality in industrialized countries can be expected as a result of an increasing uptake of prenatal diagnosis.