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Abstract: Bisphenol A (BPA) and phthalates are endocrine disruptors possibly linked to adverse reproductive and neurodevelopmental outcomes. These chemicals have commonly been measured in urine in population surveys; however, such data are limited for large populations of pregnant women, especially for the critical first trimester of pregnancy. The aim of the study was to measure BPA and phthalate metabolites in first trimester urine samples collected in a large national-scale pregnancy cohort study and to identify major predictors of exposure. Approximately 2000 women were recruited in the first trimester of pregnancy from ten sites across Canada. A questionnaire was administered to obtain demographic and socio-economic data on participants and a spot urine sample was collected and analyzed for total BPA (GC–MS/MS) and 11 phthalate metabolites (LC–MS/MS). The geometric mean (GM) maternal urinary concentration of total BPA, uncorrected for specific gravity, was 0.80 (95% CI 0.76–0.85) μg/L. Almost 88% of the women had detectable urinary concentrations of BPA. An analysis of urinary concentrations of BPA by maternal characteristics with specific gravity as a covariate in the linear model showed that the geometric mean concentrations: (1) decreased with increasing maternal age, (2) were higher in current smokers or women who quit during pregnancy compared to never smokers, and (3) tended to be higher in women who provided a fasting urine sample and who were born in Canada, and had lower incomes and education. Several of the phthalate metabolites analyzed were not prevalent in this population (MCHP, MMP, MiNP, MOP), with percentages detectable at less than 15%. The phthalate metabolites with the highest measured concentrations were MEP (GM: 32.02μg/L) and MnBP (GM: 11.59μg/L). MBzP urinary concentrations decreased with maternal age but did not differ by time of urine collection; whereas the DEHP metabolites tended to be higher in older women and when the urine was collected later in the day. This study provides the first biomonitoring results for the largest population of pregnant women sampled in the first trimester of pregnancy. The results indicate that exposure among this population of pregnant women to these chemicals is comparable to or even lower than that observed in a Canadian national population-based survey. [Copyright &y& Elsevier]

Abstract: The exposure of Aboriginal peoples in the Canadian Arctic to persistent organic pollutants (POPs) and metals through the consumption of traditional food items is well recognized; however, less information is available for Canadian immigrants. The direct comparison of blood chemical concentrations for expectant primiparous women sampled in the Inuvik and Baffin regions of the Canadian Arctic, as well as Canadian- and foreign-born women from five southern Canadian centers (Halifax, Vancouver, Hamilton, Ottawa, and Calgary), provides relative exposure information for samples of northern and southern mothers in Canada. Based on our analyses, Canadian mothers are exposed to a similar suite of contaminants; however, Inuit first birth mothers residing in the Canadian Arctic had higher age-adjusted geometric mean concentrations for several legacy POPs regulated under the Stockholm Convention, along with lead and total mercury. Significant differences in exposure were observed for Inuit mothers from Baffin who tended to demonstrate higher blood concentrations of POPs and total mercury compared with Inuit mothers from Inuvik. Conversely, northern mothers showed a significantly lower age-adjusted geometric mean concentration for a polybrominated diphenyl ether (PBDE-153) compared to southern mothers. Furthermore, southern Canadian mothers born outside of Canada showed the highest individual concentrations measured in the study: 1700μg/kg lipids for p,p′-dichlorodiphenyldichloroethylene (p,p′-DDE) and 990μg/kg lipids for β-hexachlorocyclohexane (β-HCH). Data from Cycle 1 (2007–2009) of the nationally-representative Canadian Health Measures Survey (CHMS) places these results in a national biomonitoring context and affirms that foreign-born women of child-bearing age experience higher exposures to many POPs and metals than their Canadian-born counterparts in the general population. [Copyright &y& Elsevier]

Background The Maternal- Infant Research on Environmental Chemicals ( MIREC) Study was established to obtain Canadian biomonitoring data for pregnant women and their infants, and to examine potential adverse health effects of prenatal exposure to priority environmental chemicals on pregnancy and infant health. Methods Women were recruited during the first trimester from 10 sites across Canada and were followed through delivery. Questionnaires were administered during pregnancy and post-delivery to collect information on demographics, occupation, life style, medical history, environmental exposures and diet. Information on the pregnancy and the infant was abstracted from medical charts. Maternal blood, urine, hair and breast milk, as well as cord blood and infant meconium, were collected and analysed for an extensive list of environmental biomarkers and nutrients. Additional biospecimens were stored in the study's Biobank. The MIREC Research Platform encompasses the main cohort study, the Biobank and follow-up studies. Results Of the 8716 women approached at early prenatal clinics, 5108 were eligible and 2001 agreed to participate (39%). MIREC participants tended to smoke less (5.9% vs. 10.5%), be older (mean 32.2 vs. 29.4 years) and have a higher education (62.3% vs. 35.1% with a university degree) than women giving birth in Canada. Conclusions The MIREC Study, while smaller in number of participants than several of the international cohort studies, has one of the most comprehensive datasets on prenatal exposure to multiple environmental chemicals. The biomonitoring data and biological specimen bank will make this research platform a significant resource for examining potential adverse health effects of prenatal exposure to environmental chemicals. [ABSTRACT FROM AUTHOR]

Abstract: The developing foetus is thought to be at increased risk from exposure to environmental contaminants; however, developmental exposure data is notably lacking for many contaminants. Moreover, potential regional differences or effect of place of birth on residue levels measured in pregnant women is also unknown. Therefore, as part of a multinational biomonitoring study, 125 primiparous pregnant Canadian women were recruited from five Canadian centres (Vancouver, Calgary, Hamilton, Ottawa, and Halifax). Metals in whole blood and persistent organic pollutants (POPs) in plasma were measured by inductively coupled plasma mass spectrometry (ICPMS) and gas chromatography–mass spectrometry (GCMS), respectively. Of the 125 women recruited to this study, complete data sets were available for 123 of which 103 were Canadian born. Data were analysed by analysis of covariance and linear mixed models using age and body mass index as covariates. The metals cadmium (Cd), cobalt (Co), lead (Pb), nickel (Ni), selenium (Se), and total mercury (Hg) were detected in more than 93% of the samples tested. β-Hexachlorohexane (β-HCH), oxychlordane, trans-nonachlor, 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p′-DDE), polybrominated diphenyl ether (PBDE) congeners (PBDE-153, PBDE-47), polychlorinated biphenyl (PCB) congeners (PCB-138, -153, and ‐180), and the dioxin-like PCB congener PCB-118 were quantified in greater than 70% of the samples tested. Significant differences in the concentrations of Cd, Ni, PCB-153, and p,p′-DDE were found between the centres studied. Furthermore, foreign-born pregnant women had significantly higher concentrations of Cd, β-HCH, PBDE-47, PCB-138, -153, -180, and p,p′-DDE compared to Canadian born pregnant women. Taken together, the data suggest that there are potential regional differences in contaminant body burden and place of birth may also contribute to differences in maternal residue concentrations. [Copyright &y& Elsevier]

Background: The developing fetus and pregnant woman can be exposed to a variety of environmental chemicals that may adversely affect their health. Moreover, environmental exposure and risk disparities are associated with different social determinants, including socioeconomic status (SES) and demographic indicators. Our aim was to investigate whether and how maternal concentrations of a large panel of persistent and non-persistent environmental chemicals vary according to sociodemographic and lifestyle characteristics in a large pregnancy and birth cohort.Methods: Data were analyzed from the Maternal-Infant Research on Environmental Chemicals (MIREC) Study, a cohort of pregnant women (N=2001) recruited over four years (2008-2011) in 10 cities across Canada. In all, 1890 urine and 1938 blood samples from the first trimester (1st and 3rd trimester for metals) were analysed and six sociodemographic and lifestyle indicators were assessed: maternal age, household income, parity, smoking status, country of birth and pre-pregnancy body mass index (BMI).Results: We found these indicators to be significantly associated with many of the chemicals measured in maternal blood and urine. Women born outside Canada had significantly higher concentrations of di-2-ethylhexyl and diethyl phthalate metabolites, higher levels of all metals except cadmium (Cd), as well as higher levels of polychlorinated biphenyls (PCBs) and legacy organochlorine pesticides (OCPs). Nulliparity was associated with higher concentrations of dialkyl phosphates (DAPs), arsenic, dimethylarsinic acid (DMAA), perfluoroalkyl substances (PFASs) and many of the persistent organic pollutants. Smokers had higher levels of bisphenol A, Cd and perfluorohexane sulfonate, while those women who had never smoked had higher levels of triclosan, DMAA, manganese and some OCPs.Conclusion: Our results demonstrated that inequitable distribution of exposure to chemicals among populations within a country can occur. Sociodemographic and lifestyle factors are an important component of a thorough risk assessment as they can impact the degree of exposure and may modify the individual's susceptibility to potential health effects due to differences in lifestyle, cultural diets, and aging. [ABSTRACT FROM AUTHOR]

Given the susceptibility of the fetus to toxicants, it is important to estimate their exposure. Approximately 2000 pregnant women were recruited in 2008–2011 from 10 cities across Canada. Cd, Pb, Mn and total Hg were measured in maternal blood from the 1st and 3rd trimesters, umbilical cord blood, and infant meconium. Nutrient intakes of vitamin D, iron, and calcium (Ca) were assessed using a food frequency questionnaire and a dietary supplement questionnaire. Median concentrations in 1st trimester maternal blood (n = 1938) were 0.20, 8.79 and 0.70 μg/L for Cd, Mn and Hg, respectively, and 0.60 μg/dL for Pb. While the median difference between the paired 1st and 3rd trimester concentrations of Cd was 0, there was a significant decrease in Pb (0.04 μg/dL) and Hg (0.12 μg/L) and an increase in Mn (3.30 μg/L) concentrations over the course of the pregnancy. While Cd was rarely detected in cord blood (19%) or meconium (3%), median Pb (0.77 μg/dL), Mn (31.87 μg/L) and Hg (0.80 μg/L) concentrations in cord blood were significantly higher than in maternal blood. Significant negative associations were observed between estimated Ca intake and maternal Cd, Pb, Mn and Hg, as well as cord blood Pb. Vitamin D intake was associated with lower maternal Cd, Pb, and Mn as well as Pb in cord blood. Even at current metal exposure levels, increasing dietary Ca and vitamin D intake during pregnancy may be associated with lower maternal blood Pb and Cd concentrations and lower Pb in cord blood. [ABSTRACT FROM AUTHOR]