Because the neural tube closes in the first four weeks of gestation, often before many women even know they are pregnant, many countries in time decided to implement mandatory food fortification programs. A meta-analysis of global birth prevalence of spina bifida showed that when mandatory fortification was compared to countries with healthcare professionals advising women but no mandatory fortification program, there was a 30% reduction in live births with spina bifida, with some countries reported a greater than 50% reduction.Over 80 countries require folic acid fortification in some foods. Fortification of rice is common. The USDA has required the fortification of flour since 1998. Since then, Hispanics in the United States have seen the greatest reduction of neural tube defects. Canada has mandated folic acid fortification of flour since 1998 which has resulted in a 42% decrease in neural tube defects. Fortification of wheat and corn flour, milk and rice is required in Costa Rica which has led to a reduction of neural tube defects of as much as 60%. Epidemiology
Folate deficiency is very rare in countries with folic acid fortification programs. Overall, the worldwide prevalence of anemia due to folic acid deficiency is very low. However, data on the prevalence of deficiency amongst specific high risk groups is lacking.
Birth injury refers to damage or injury to the child before, during, or just after the birthing process. "Birth trauma" refers specifically to mechanical damage sustained during delivery (such as nerve damage and broken bones).The term "birth injury" may be used in two different ways:

the ICD-10 uses "birth injury" and "birth trauma" interchangeably to refer to mechanical injuries sustained during delivery;
the legal community uses "birth injury" to refer to any damage or injury sustained during pregnancy, during delivery, or just after delivery, including injuries caused by trauma.Birth injuries must be distinguished from birth defects. "Birth defect" refers to damage that occurs while the fetus is in the womb, which may be caused by genetic mutations, infections, or exposure to toxins. There are more than 4,000 types of birth defects. Causes
Difficult labor (dystocia)
Difficult labor, also known as dystocia or obstructed labor, occurs when the child cannot easily pass through the birth canal. This can result in fetal distress or physical trauma to the child, especially broken clavicles and damage to the brachial plexus nerves. It can also deprive the child of oxygen as the umbilical cord is pinched, potentially causing brain damage or death.Difficult labor may occur because the baby is abnormally large (macrosomia), because the mothers pelvis or birth canal is small or deformed, or because the baby is in an abnormal presentation for the birth (such as breech or transverse presentation). External causes
Fetal malformations and birth injuries may occur as a result of exposure to environmental toxins such as mercury or lead.