ESPE Abstracts

Background: Significant changes in metabolism and water equilibrium are registered during pregnancy. However, very limited previous investigations have been carried out on variations of exposure levels and metabolism of non-persistent environmental chemicals during pregnancy.

Objective and hypotheses: The objective of this longitudinal study is to describe variation in exposure of pregnant women to environmental chemicals. We hypothesise that variation in exposure levels between trimesters are observed, and that individuals maintain an either low or high exposure level with limited intra-subject variation.

Method: Serum samples (n=534) from 128 women (average 4.2 per woman) collected 2000–2002 were analysed for: Phenols: bisphenol A (BPA), triclosan (TCS), triclocarban (TCCB), benzophenone-3 (BP-3), 2,4-dichlorophenol (2,4-DCP), 2,5- dichlorophenol (2,5-DCP), 2,4,5-trichlorophenol (2,4,5-TCP), 2-phenylphenol (2-PP), 4-phenylphenol (4-PP); Parabens: methyl- (MeP), ethyl- (EtP), iso-propyl- (i-PrP), n-propyl- (n-PrP), iso-butyl- (i-BuP), n-butyl (n-BuP) and benzyl paraben (BzP). Exposure to phthalates will be measured. The samples were selected to correspond to first (n=77), second (n=250) and third trimester (n=207). Chemicals were analysed with TurboFlow-LC-MS/MS. P-values calculated with Krustall-Wallis non parametric test. Intraclass correlation coefficients (ICC) were calculated using reliability analyses in SPSS.

Results: BPA, BP-3, 2-PP, MeP and n-PrP were detectable in more than half of the tested population, TCS and EtP were detectable in 25% (P-values ranging 0.08–0.62). There does not seem to be a change in median exposure levels between the three trimesters. Single measures ICCs for the within-person variance of repeated measures for BPA=0.007, BP-3=0.153, 2-PP=0.149, MeP=0.027 and n-PrP=0.586.

Conclusion: Exposure of pregnant women assessed by serum concentrations of phenols and parabens does not appear to vary between trimesters. In accordance with other study populations, individual exposure levels tend to stay within the same quartile over time.

Funding: CEHOS – The Danish National Center of Endocrine Disruption.