Triclosan (TCS) is a synthetic antibacterial chemical that is used in personal care products and is measurable in urine. Urinary TCS has been associated with allergy in children in Norway and the United States. A reasonable degree of temporal reliability of TCS urinary concentrations has been reported among U.S. children as well as for Puerto Rican pregnant women. We examined the reliability of TCS measures in urine among Norwegian pregnant women. Triclosan was measured in spot urine samples collected in gestational weeks 17, 23, and 29 from 45 women in The Norwegian Mother and Child Cohort Study (MoBa) enrolled in 2007 and 2008. Spearman’s rank correlation coefficient (rs) and intraclass correlation coefficient (ICC) statistics were calculated. Fifty-six percent of the 45 women had a least one sample with a value above the method limit of detection (2.3 µg/L). The correlation coefficients were 0.61 for TCS concentrations at 17 and 23 weeks and 0.49 for concentrations at 17 and 29 weeks. For the three time points, the ICC was 0.49. The reliability of TCS concentrations in repeated urine samples from pregnant Norwegian women was reasonably good, suggesting a single urine sample can adequately represent TCS exposure during pregnancy
