Community water fluoridation and urinary fluoride concentrations in a national sample of pregnant women in Canada

Background: Fluoride exposures have not been established for pregnant women who live in regions with and without community water fluoridation. Objective: Our aim was to measure urinary fluoride levels during pregnancy. We also assessed the contribution of drinking-water and tea consumption habits to maternal urinary fluoride (MUF) concentrations and evaluated the impact of various dilution correction standards, including adjustment for urinary creatinine and specific gravity (SG). Methods: We measured MUF concentrations in spot samples collected in each trimester of pregnancy from 1,566 pregnant women in the Maternal–Infant Research on Environmental Chemicals cohort. We calculated intraclass correlation coefficients (ICCs) to assess variability in MUF concentrations across pregnancy. We used regression analyses to estimate associations between MUF levels, tea consumption, and water fluoride concentrations as measured by water treatment plants. Results: Creatinine-adjusted MUF values (mean±SD; milligrams p...