Department of Pediatrics, University of Washington, Seattle, WA 98105, USA. David.Shurtleff@seattlechildrens.org.
This review article combines four disparate observations about Neural Tube Defects (NTDs). They are the worldwide decline in the birth incidence that began prior to prenatal diagnosis; family recurrence risks; the effect of prenatal diagnosis and termination of affected pregnancies; and the effect of folic acid.