Phthalate and bisphenol A exposure among pregnant women in Canada--results from the MIREC study.
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: 32.02 μg/L) and MnBP (GM: 11.59 μg/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.
Population Studies Division, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Canada. Electronic address: Tye.arbuckle@hc-sc.gc.ca.
Tye E
TE
Arbuckle
Population Studies Division, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Canada.
Karelyn
K
Davis
Population Studies Division, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Canada.
Leonora
L
Marro
Population Studies Division, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Canada.
Mandy
M
Fisher
Chemicals Surveillance Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Canada.
Melissa
M
Legrand
Le Centre de Toxicologie du Québec, Institut nationale de Santé Publique Québec, Québec, Canada.
Alain
A
LeBlanc
Le Centre de Toxicologie du Québec, Institut nationale de Santé Publique Québec, Québec, Canada.
Eric
E
Gaudreau
Division of Reproductive Biology, Department of Obstetrics and Gynecology, McMaster University, Hamilton, Canada.
Warren G
WG
Foster
Population Studies Division, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Canada.
Voleak
V
Choeurng
Sainte Justine University Hospital Research Center, University of Montreal, Montreal, Canada.
William D
WD
Fraser
D000293:Adolescent; D000328:Adult; D001559:Benzhydryl Compounds / Q000378:metabolism / Q000652:urine*; D002170:Canada; D002849:Chromatography, Gas; D002851:Chromatography, High Pressure Liquid; D015331:Cohort Studies; D003710:Demography; D004785:Environmental Pollutants / Q000737:chemistry / Q000378:metabolism / Q000652:urine*; D005260:Female; D006801:Humans; D018811:Maternal Exposure; D010636:Phenols / Q000378:metabolism / Q000652:urine*; D010795:Phthalic Acids / Q000378:metabolism / Q000652:urine*; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D012907:Smoking; D011795:Surveys and Questionnaires; D053719:Tandem Mass Spectrometry; D055815:Young Adult; D000098826:Bisphenol A Compounds
D001559:Benzhydryl Compounds; D004785:Environmental Pollutants; D010636:Phenols; D010795:Phthalic Acids; C032279:phthalic acid; C006780:bisphenol A; D000098826:Bisphenol A Compounds
Biomonitoring; Bisphenol A; Phthalates; Pregnancy; Urine