 For example, spina bifida affects approximately 1,500 births annually in the United States, or about 3.5 in every 10,000 (0.035% of US births), which has decreased from around 5 per 10,000 (0.05% of US births) since folate fortification of grain products was started.The number of deaths in the US each year due to neural tube defects also declined from 1,200 before folate fortification was started to 840.There are two types of NTDs