Purpose: Neural tube defects (NTDs) are the most common malformations of the central nervous system (CNS). There is continuing research for the identification of risk factors and interventions for prevention of NTDs. The aim of this study was to investigate the maternal second trimester blood levels of selected heavy metals namely, arsenic (As), cadmium (Cd), mercury (Hg), manganese (Mn), nickel (Ni), and lead (Pb) and their possible relation with the occurrence of NTDs.
Methods: Twenty-one healthy second trimester pregnant women with fetuses affected with NTD (cases) were matched with 21 healthy pregnant women with unaffected fetuses (controls) with respect to age, body mass index (BMI), and gestational age. Maternal blood levels of heavy metals were measured after an overnight fasting period.
Results: No significant differences were observed in terms of maternal blood levels of As, Cd, Hg, and Ni between NTD-affected and unaffected pregnancies. The blood Pb and Mn levels were found to be higher in pregnant women with a fetus affected with NTD when compared with pregnant women with unaffected fetuses (for Pb, in cases 12.3 ± 5.5 µg/L, in controls 7.8 ± 2.4 µg/L; for Mn in cases 3.6 ± 1.4 µg/L, in controls 2.4 ± 1.0 µg/L, p < .05).
Conclusions: High maternal second trimester blood levels of Pb and Mn during pregnancy are associated with NTDs in the newborn.
Keywords: Neural tube defect; heavy metal; lead; manganese.