Leading Categories of Birth Defects

Leading causes of birth defects.The estimated incidences for the leading categories of birth defects are provided in the table below. Birth defects are grouped into three major categories:

  1. structural/metabolic;
  2. congenital infections; and
  3. other conditions.

Birth defects of the heart and circulatory system affect more infants than any other type of birth defect. Of all infants born each year, approximately 1 in 115 has heart and/or circulatory defects.


Birth Defects Estimated Incidence
Structural / Metabolic  
Heart and circulation 1 in 115 births
Muscles and skeleton 1 in 130 births
Club foot 1 in 735 births
Cleft lip / palate 1 in 930 births
Genital and urinary tract 1 in 135 births
Nervous system and eye 1 in 235 births
Anencephaly 1 in 8,000 births
Spina bifida 1 in 2,000 births
Chromosomal syndromes 1 in 600 births
Down syndrome (Trisomy 21) 1 in 900 births
Respiratory tract 1 in 900 births
Metabolic disorders 1 in 3,500 births
PKU 1 in 12,000 births
Rh disease 1 in 1,400 births
Fetal alcohol syndrome 1 in 1,000 births


Sources: March of Dimes Perinatal Data Center, 2000. Unpublished review of the literature and information from various state and regional, birth defects surveillance systems (California, Iowa, Metropolitan Atlanta, New York, and Texas).