To reduce the risk of neural tube birth defects in infants, the mother-to-be should consume adequate amounts of prior to conception.

Folic acid.

Explanation:

Vitamins are the important chemicals compounds required in the body in the adequate small amount. Their deficiency in the individual might cause a characteristics disease.

The proper vitamins and diet supplements are necessary for the pregnant woman. Their deficiency can cause abnormal development of the offspring. The folic acid is a type of the vitamin B and its deficiency may be responsible for the neural tube defects in the child.

Thus, the answer is folic acid.