Association between gestational arsenic exposure and intrauterine growth restriction: the role of folate content

Abstract

Gestational arsenic (As) exposure is associated with intrauterine growth restriction (IUGR). This study explored the association among gestational As exposure, IUGR, and reduction of folate content in maternal and umbilical plasma from 530 mother-and-singleton-offspring pairs. Birth weight (BW) was negatively correlated with As in maternal plasma (r=-0.194, P<0.001) and umbilical plasma (r=-0.235, P<0.001). By contrast, a positive correlation was found between BW and maternal folate content (r=0.198, P<0.001). The subjects were divided into As-L and As-H groups. The influence of As-H on small for gestational age (SGA) infants, a marker of IUGR, was evaluated by multivariate logistic regression that excludes interferences of gestational age, infant sex, and other confounding factors. Mothers with As-H had an elevated risk of SGA infants (adjusted OR, 2.370; P<0.05). Interestingly, maternal folate content was lower in subjects with As-H than those with As-L (22.4±10.7 vs 11.2±6.7 nmol/L, P<0.001). Linear correlation models show that As level was negatively correlated with folate content in maternal plasma (r=-0.615, P<0.001) and umbilical plasma (r=-0.209, P<0.001). Moreover, maternal folate reduction has an obvious mediating effect between increased As and decreased BW (β=-0.078, P<0.05). Our results indicate that folate reduction may be a mediator between gestational As exposure and IUGR.

Keywords: Arsenic pregnancy; Birth weight; Folate mediator; Intrauterine growth restriction.