Introduction & Objective: After cardiac defects, neural–tube defects (NTD) are the most congenital structural defects with a worldwide incidence of 1.4 to 2 per 1000 live births. This defect is due to failure of the neural tube to close spontaneously between the 3rd and 4th wk of uterine development. The control of risk factors related to NTD, decreases the  psychologic  problems  and it is cost effect.

Materials & Methods: Of 14588 women that referred to delivery room in Fatemiyeh  Hospital from March 1998 until Sep 2002, 55 women had fetus or neonate with NTD (case group). 100 women with normal neonate in a systematic randomized  sampling were chosen as a control group.

Results: During 4.5 years, 55 women (3.7 in 1000) had fetus or neonate with NTD. Between two groups there were statistical difference in the rate of hydramniose during pregnancy )p<0.001, OR=0.045 CI=0.005-0.3) and sever fever (p=0.001,OR=0.05 CI=0.006-0.44)) around the conception’s time and early pregnancy. There were no statistical difference between two groups in folic acid consuming.

Conclusion: In recent years, many studies were carried out for survey of folic acid deficiency on NTD. In this research both groups consumed folic acid from the third month of pregnancy and there was no difference in consuming of the folic acid supplement between two groups. The NTD development is between the 3rd and 4th week of pregnancy, so intake of 400µcg folic acid daily (according to CDC and ACOG recommendations) in all women in reproductive age that referred to health care setting is offered, also notice to the fever around the ovulation time as an effective factor in decrease incidence of NTD is important.