Health Professionals:

Folic Acid and NTDs

Rates of NTDs

• Each year approximately 3,000 pregnancies in the United States are affected by a NTD (CDC, 2004).
• The rate of spina bifida in the U.S. for 1999-2007 was 3.2 per 10,000 live births (Canfield et al., 2014). The prevalence of spina bifida varies among states as well as among different ethnic groups, with Hispanics having the highest and Asians and Pacific Islanders having the lowest rates (Canfield et al., 2014).
• The rate of anencephaly in the U.S. for 1999-2007 was 1.3 per 10,000 live births (Canfield et al., 2014).
• In 2012, the rate of spina bifida in Florida was 2.2 per 10,000 live births and the rate of anencephaly was 0.7 per 10,000 live births (Florida Department of Health).

Associated Causes

Most NTDs occur as isolated defects, rather than in association with other malformations. While the latter are sometimes due to single gene defects, chromosomal abnormalities, or teratogenic agents, the cause of isolated NTDs is not fully understood. It is assumed, however, to be multifactorial, that is, the result of an interplay between genetic and environmental factors. Several factors have been associated with an increased risk for NTDs (Cabrera et al., 2004; CDC, 2009; Chitayat et al., 2016; Halsted et al., 2010; Yazdy et al., 2013):

• Low folate status or intake, which may be affected by:

• Previous NTD-affected pregnancy
• Use of certain medications, including anticonvulsants, folic acid antagonist medications, and opioids.
• Maternal hyperthermia during early pregnancy (e.g., febrile disease or hot tub use)
• Maternal obesity and diabetes
• Race/ethnicity (Mexican-American women living in the U.S. who were born in Mexico may be at higher risk)
• Maternal smoking
• Low socioeconomic status
• Exposure to fumonisin B1, a mycotoxin found as a contaminant in corn