Prenatal Exposure to Environmental Phenols: Concentrations in Amniotic Fluid and Variability in Urinary Concentrations during Pregnancy

Abstract

Background: Maternal urinary biomarkers are often used to assess fetal exposure to phenols and their precursors. Their effectiveness as a measure of exposure in epidemiological studies depends on their variability during pregnancy and their ability to accurately predict fetal exposure.Objectives: We assessed the relationship between urinary and amniotic fluid concentrations of nine environmental phenols, and the reproducibility of urinary concentrations, among pregnant women.Methods: Seventy-one women referred for amniocentesis were included. Maternal urine was collected at the time of the amniocentesis appointment and on two subsequent occasions. Urine and amniotic fluid were analyzed for 2,4- and 2,5-dichlorophenols, bisphenol A, benzophenone-3, triclosan, and methyl-, ethyl-, propyl-, and butylparabens using online solid phase extraction–high performance liquid chromatography–isotope dilution tandem mass spectrometry.Results: Only benzophenone-3 and propylparaben were detectable in more than half of the amniotic fluid samples; for these phenols, concentrations in amniotic fluid and maternal urine collected on the same day were positively correlated (ρ = 0.53 and 0.32, respectively). Other phenols were detected infrequently in amniotic fluid (e.g., bisphenol A was detected in only two samples). The intraclass correlation coefficients (ICCs) of urinary concentrations in samples from individual women ranged from 0.48 and 0.62 for all phenols except bisphenol A (ICC = 0.11).Conclusion: Amniotic fluid detection frequencies for most phenols were low. The reproducibility of urine measures was poor for bisphenol A, but good for the other phenols. Although a single sample may provide a reasonable estimate of exposure for some phenols, collecting multiple urine samples during pregnancy is an option to reduce exposure measurement error in studies regarding the effects of phenol prenatal exposure on health.Citation: Philippat C, Wolff MS, Calafat AM, Ye X, Bausell R, Meadows M, Stone J, Slama R, Engel SM. 2013. Prenatal exposure to environmental phenols: concentrations in amniotic fluid and variability in urinary concentrations during pregnancy. Environ Health Perspect 121:1225–1231; http://dx.doi.org/10.1289/ehp.1206335

Systematic review of the literature on triclosan and health outcomes in humans

“…For example, as noted by Koch et al (2014), "In many cases the relatively high ICC values in the current study derived from large between-individual differences in exposure levels rather than from low within-individual variation … " Koch et al further observe that a single spot sample may "substantially over-or under-represent average exposure to that individual." Similarly, referring to ICCs of around 0.5-0.6, Philippat et al (2013) stated: "Although a correlation of this magnitude is greater than reported for many other rapidly metabolized compounds, it may still result in bias due to exposure misclassification if the putative window of susceptibility is distant from the sample collection period … To limit the effects of exposure misclassification, studies of the effects of phenol prenatal exposure on health should try to collect multiple urine samples during pregnancy. "…”

Biological monitoring of petrochemical industry workers exposed to benzene, toluene, xylenes, methyl ethyl ketone, and phenol in Southern Iran

“…Data from this study showed that t,t-MA, HA, and MHA have a good correlation with concentrations of the related hydrocarbons. Many studies have confirmed these results (33)(34)(35), but some studies reported a poor correlation between t,t-MA and benzene (36). Angerer et al reported a poor correlation between HA and toluene (37).…”

Impact of Pregnancy on the Levels of the Sunscreen Agent Benzophenone-3: Data from NHANES 2005-2010

“…This is an area which requires future scientific investigations. The decreasing concentrations of BP-3seen in urine during pregnancy probably reflect transfer of BP-3 to the developing fetus since BP-3 has previously been detected in amniotic fluid [5]. The observed decreases in concentrations of BP-3 during pregnancy could potentially be due to modification of drug half-life.…”

“…BP-3 has also been detected in both raw and water treated by water filtration plants [2] in California, in waste water in Slovenia and in Switzerland [3,4]. BP-3 has been detected in urine of pregnant females and more than half of the amniotic fluid samples [5] with a high correlation of 0.53 between their concentrations in maternal urine and amniotic fluid. In a study of 105 pregnant females in Northern Puerto Rico [6], BP-3 was detected in 100% the urine samples and the levels of BP-3 among Puerto Rican pregnant females were found to be higher than females of reproductive age in general US population (52.2 ng/mL vs. 38.6 ng/mL for NHANES 2007-2008 and 36.3 ng/mL for NHANES [2009][2010].…”