Maternal drinking water arsenic exposure and perinatal outcomes in Inner Mongolia, China

Abstract

Background: Bayingnormen is a region located in western Inner Mongolia China with a population that is exposed to a wide range of drinking water Arsenic concentrations. This study evaluated the relationship between maternal drinking water arsenic exposure and perinatal endpoints (term birthweight, preterm birth, stillbirth, neonatal death) in this region.

Methods: An analysis was conducted of all singleton deliveries in a defined geographic area of Inner Mongolia from December 1996 to December 1999 (n = 9,890). Outcome and covariate data were abstracted from prenatal care records. Exposure was based on well-water measures for the maternal subvillage. Mean birthweight at term was compared across four arsenic categories using analysis of covariance. Odds ratios (ORs) for stillbirth, preterm birth, and neonatal death were estimated by logistic regression with arsenic exposure dichotomised at 50 µg/L.

Main results: Term birthweight was 0.05 kg higher (95% CI 0.02 to 0.08) in the highest exposure category (>100 µg/L) compared to the referent (below limit of detection to 20 µg/L). Arsenic >50 µg/L was associated with an increased risk of neonatal death (OR 2.01, 95% CI 1.12 to 3.59). No relationship was found between maternal arsenic exposure and preterm or stillbirth delivery.

Conclusions: At the levels observed in our study, arsenic does not appear to contribute to adverse birth outcomes. Exposure may play a role in neonatal death, but the neonatal death rate in this population was low and this potential association merits further research.