Table 1.

Comparison of Three Approaches Used to Assess Congenital Anomalies: Features, Strengths, and Limitations

Study	Approach	Ascertains Major or Minor Anomalies	Timing	Strengths	Limitations
North American Antiepileptic Drug Pregnancy Registry	Maternal report followed by review of medical records of examinations up to 12 wks of life	Major only	Defects identified in first 12 wks	Less costly Focuses on major congenital anomalies – more likely to be of clinical significance Easiest approach to implement	Depends on maternal report and medical record review, neither of which is completely reliable No physical examination by study clinician – nonstudy clinicians less likely to consistently identify and document anomalies Includes defects identified in first 12 wks of life – defects identified later are excluded Minor anomalies not assessed, patterns of minor anomalies will not be identified Does not include neurobehavioral assessment
National Children's Study	Photographic protocol (15 images and 3 10-second videos) and Physical Assessment (checklist of 25 features) completed by trained study personnel	Major and minor anomalies	Exam conducted at birth, 6, and 12 mo of age	Less costly than OTIS approach Study personnel can be trained to conduct protocol – thus, less logistically challenging (more qualified examiners) than OTIS approach Includes photographs Includes checklist of a limited number of minor anomalies	Reliability among examiners has not yet been established More costly than AED Pregnancy Registry approach Ascertainment at birth, 6 and 12 mo – might miss defects that are more apparent at other ages Focus on minor anomalies might mean that an increase in major defects could be missed Does not include neurobehavioral assessment
Organization of Teratology Information Specialists	Physical examination within the first 6 mo of life by trained study dysmorphologists	Major and minor anomalies	Single exam during first 6 mo of life	Uses trained dysmorphologists who may be more likely to identify patterns of anomalies Includes comprehensive physical examination Consistency among examiners has been demonstrated Includes photographs Includes medical records review Includes checklist of minor anomalies	Most costly approach Time–consuming and logistically challenging Number of dysmorphologists is limited Ascertainment at a single point in time – might miss defects that are more apparent at other ages Focus on minor anomalies might mean that an increase in major defect could be missed Does not typically include neurobehavioral assessment, although this could be added

Abbreviations: AED, antiepileptic drug; OTIS, Organization of Teratology Information Specialists.