Table 1: Birth Defects Studied, System Affected, BD, NCBDDD, CDC

Table 1. Birth Defects Studied in the National Birth Defects Prevention Study by System Affected
System Affected	Birth Defects Studied
Cardiovascular	Conotruncal heart defects, septal heart defects, obstructive heart defects, atrioventricular septal defects, single ventricle, anomalous pulmonary venous return, heterotaxy, Ebstein malformation
Central nervous system	Neural tube defects, hydrocephaly, holoprosencephaly, Dandy-Walker malformation
Eye	Anophthalmia/microphthalmia, congenital cataracts, glaucoma
Ear	Anotia/microtia
Orofacial	Choanal atresia, cleft lip, cleft palate
Gastrointestinal	Esophageal atresia and tracheoesophageal fistula, intestinal atresia, biliary atresia
Genitourinary	Renal agenesis (bilateral), hypospadias (2nd or 3rd degree)
Musculoskeletal	Diaphragmatic hernia, gastroschisis, omphalocele, limb deficiency, craniosynostosis, bladder exstrophy, cloacal exstrophy, sacral agenesis/caudal regression
Non-system-specific	Amniotic band sequence