Maternal factors for neural tube defects in offspring: An umbrella review

We conducted an umbrella review focusing on maternal risk factors during pregnancy associated with neural tube defects (NTDs).

Our search was in databases PubMed, Scopus, and Web of Science. We specifically targeted meta-analyses examining maternal factors during pregnancy in relation to NTDs. The comparison involved assessing metrics such as odds ratio (OR) or related risk ratios reported in the included studies, as well as parameters like heterogeneity (I²), 95% prediction interval, small-study effects, excess significance biases, and sensitivity analysis.

Three risk factors for fetal NTDs, namely hyperthermia with an OR of 1.92, obesity with an OR of 1.68, and passive smoking with an OR of 1.90, were classified as highly suggestive evidence (Class II). Influenza, with an OR of 3.33, was considered a risk factor with suggestive evidence (Class III). Multivitamin supplementation during pregnancy, with an OR of 0.76, and low maternal vitamin B12, with an OR of 2.41, were categorized as weak evidence (Class IV).

We identified four risk factors including hyperthermia, influenza, obesity, and passive smoking as suggestive or highly suggestive evidence for NTDs. Low maternal vitamin B12 was identified as a risk factor for NTDs, supported by weak evidence.