Distribution of neural tube defects as a function of maternal weight: No apparent correlation

Objectives: Maternal nutritional deficiency is an important predisposing factor to congenital neural tube defects (NTDs). It was hypothesized that obese women may have an increased risk for NTDs. The aim of the present study was to address this question in a large cohort. Methods: A total of 72,915 consecutive cases of biochemical screening that had documented maternal weights and pregnancy outcomes were identified from the Quest Diagnostic Laboratories database. Patients were divided into five ranges of maternal weights, and the incidence of NTDs was calculated for each group. Based on the different definitions of maternal overweight, the data were also analyzed based on 2 groups only, obese and nonobese, using three cutoff points. Results: Seventy-nine pregnancies were complicated by NTDs (incidence of 1.08 per 1,000 pregnancies). Differences between maternal weights ranges were not found to be statistically significant (chi(2) = 5.997, p = 0.19, power = 0.99). Differences between obese and nonobese mothers were not found to be statistically significant for all three analyses as well. Conclusions: Our present results do not support an association between maternal obesity and NTDs.