Estimates of birth prevalence rates of spina bifida in the United States from computer-generated maps.

A computer-generated mapping procedure was developed to estimate geographic and race-specific birth prevalence rates of open spina bifida. The estimates are based on birth certificate data adjusted for underascertainment. Separate maps were produced for white births and black births. For both races there is a general decreasing rate of spina bifida from east to west. The highest rates are eight per 10,000 total births for whites in Southern Appalachia, and the lowest rates are less than one per 10,000 for blacks in the Rocky Mountain states and the Pacific Northwest. Until more exact data are available, these maps represent the best current available data on racial and geographic birth prevalence rates in the United States. They are useful for program planning and as an aid in interpreting maternal serum alpha-fetoprotein levels to detect neural tube defects.