Risk Factors for Neural-Tube Defects Detected in Utero: A Prospective Community-Based Study from Addis Ababa.

Background: A recent community-based study from Addis Ababa identifying Neural Tube Defect (NTD) cases by ultrasound examination of pregnant women showed a higher prevalence of 17 per 1000 fetuses. The risk factors behind the high prevalence remain unclear.

Methods: Altogether 891 of the 958 women participated in the ultrasound examination. Thirteen with unaffected twin pregnancies were excluded. Among 878 singleton pregnancies, 15 NTD cases were identified. Serum Folate, vitamin B12, and homocysteine levels were measured in case-mothers and a sub-set of 28 noncase mothers. Because of the modest sample size, exact logistic regression analysis was used to estimate associations between risk factors and NTDs.

Results: Serum vitamin status was generally poor for participants in the study. Still, relatively higher values of folate or vitamin B12 in serum, appeared to be protective for NTD (odds ratio [OR] = 0.61 per ng/ml, 95% Confidence interval [CI]: 0.42-0.85 and OR = 0.67 per 100 pg/ml, 95% CI: 0.41-1.02, respectively). High serum homocysteine was associated with higher risk of NTD (OR = 1.3 per μmol/l, 95% CI: 1.02-1.8). Women aged 30 years or more had an OR of 3.5 (95% CI: 1.1-12) for having a NTD child, and families with NTD children had lower household income. Women in the NTD group also had more spontaneous abortions or stillbirths in previous pregnancies. Self-reported intake of folate did not appear to protect against NTDs.

Conclusions: Within this high-prevalence community, poor vitamin status was identified as a risk factor for NTDs detected at ultrasound examination. Improving food security and fortification of foods or food ingredients could be alternative measures.