Major congenital anomalies affect 2-3% of neonates. Anomalies may be detected in another 2-3% during the first five years of life, thereby affecting 4-6% of all children. Congenital anomalies may be genetic or environmental in origin. The underlying etiology is undetermined in 50-60% of all major anomalies, multifactorial in 20-25%, genetic in 7-8%, chromosomal in 6-7%, and teratogenic in 6%. Primary prevention is of major importance, since treatment for most anomalies is either impossible or difficult. Major preventive goals for our population are: (1) decreasing the frequency of consanguineous marriages, which increase the incidence of rare autosomal recessive disorders, (2) decreasing the frequency of births among >35-year-old women, which increase chromosomal disorders, mainly Down syndrome, and (3) improving the socioeconomic and environmental factors that affect the frequency of multifactorial diseases. Antenatal maternal factors, including dietary folate intake, smoking, caffeine and alcohol consumption, rubella infection, and uncontrolled diabetes, may also affect the frequency of major anomalies.

Keywords: konjenital anomaliler, önleme, akraba evliliği, ileri anne yaşı, multifaktöriyel hastalıklar, çevresel etkenler.