Lack of folic acid leads to anaemia. It is of value in the treatment of macrocytic anaemias, particularly those associated with metabolic diseases of the digestive system and and nutritional deficiencies. Neural tube defects (such as spina bifida) in foetuses are linked with a deficit of folic acid in the diet of the mother from the time of conception to the 12th week of pregnancy. To protect against spina bifida, it is estimated that pregnant women need three times the amount of folic acid normally occurring in their diet.