Objective: This study was conducted to determine the serum level of folic acid and vitamin B12 in neural tube defects pregnancies (NTD) and healthy controls in Northern Iran.

Methods: This case-control study was performed on women with neural tube defects pregnancies and controls with unaffected pregnancies in Northern Iran during 2006. Twenty three pregnant women whose pregnancies were diagnosed as NTD by a second-trimester ultrasonographic examination were recruited as cases. The control group (n=23) consisted of women who were selected among socio-economic status (SES) matched women who had a normal targeted ultrasound during the second trimester with documented normal fet al outcome. Fetal NTD was suspected with targeted second-trimester ultrasound during the 16^th week of gestation and confirmed with high maternal serum α-fetoprotein levels. Folate, vitamin B₁₂, homocysteine and alpha fetoprotein were evaluated after target ultrasonography.

Findings: Serum alpha fetoprotein level (mean ± SD) in cases and controls was 120.2±64.1 and 50±33.5 iu/ml, respectively (P<0.05). The mean ± SD folate in cases and controls was 8.4±4.2 versus 9.3±4.2 ng/ml, respectively. This difference was not significant. Folate deficiency was found in 30.4% of the cases and 13% of the controls (OR = 2.9, 95%: 0.54-19.8). Vitamin B12 deficiency was found in 13 % of cases and 17.7% of the controls (OR=0.7, 95%: 0.1-4.9).

Conclusion: This study showed that the probability of having a newborn with NTDs in maternal folate deficiency is three times higher than with normal folate in Northern Iran.