METROPOLITAN ATLANTA CONGENITAL DEFECTS PROGRAM
Figure 2. Trends in anencephaly and spina bifida, including prenatally ascertained cases, before and after fortification, Metro- politan Atlanta Congenital Defects Pro- gram, 1968-2000.
MACDP confirmed that 400 micrograms of folic acid daily significantly reduces the risk for NTDs (Berry et al., ‘99). Additional analyses using these data sets indicate that the risks for other birth defects might be reduced as well with use of multivitamins or folic acid (Botto et al., ‘96; Yang et al., ‘97; Itikala et al., ‘01; Myers et al., ‘01).
Efforts to evaluate the effectiveness of the folic acid prevention activities in the United States rely on the ability to document a decrease in the birth prevalence of NTDs. MACDP data, pooled with data from the NBDPN, have
shown a significant decrease in NTD rates in the years after fortification (Williams et al., ‘02).
MACDP-based studies of other risk factors have led also to additional recommendations to reduce the risk of birth defects. For example, a study using MACDP data along with data from six other state programs found a six-fold increased risk for transverse limb reductions after chori- onic villus sampling (Olney et al., ‘95). This led to recom- mendations for counseling women considering prenatal diagnosis (CDC, ‘95).
Birth Defects Research (Part A) 67:617–624 (2003)