Exposures to environmental pollutants in utero may increase the risk of adverse health effects. We measured the concentrations of 59 potentially harmful chemicals in 77 maternal and 65 paired umbilical cord blood samples collected in San Francisco during 2010-11, including polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polybrominated diphenyl ethers (PBDEs), hydroxylated PBDEs (OH-PBDEs), and perfluorinated compounds (PFCs) in serum, and metals in whole blood. Consistent with previous studies, we found evidence that concentrations of mercury (Hg) and lower-brominated PBDEs were often higher in umbilical cord blood or serum than in maternal samples (median cord:maternal ratio > 1), while for most PFCs and lead (Pb), concentrations in cord blood or serum were generally equal to or lower than their maternal pair (median cord:maternal ratio ≤ 1). In contrast to the conclusions of a recent review, we found evidence that several PCBs and OCPs were also often higher in cord than maternal serum (median cord:maternal ratio > 1) when concentrations are assessed on a lipid-adjusted basis. Our findings suggest that for many chemicals, fetuses may experience higher exposures than their mothers, and highlight the need to characterize potential health risks and inform policies aimed at reducing sources of exposure.

Breast milk samples collected during 2003-2005 from 82 first-time mothers in 24 communities located throughout California contained levels of polybrominated diphenyl ethers (∑(tri-hexa (8))PBDEs; median = 53.3 ng/g lw, range = 9.60-1291) and polychlorinated biphenyls (∑(12)PCBs; median = 73.4 ng/g lw, range = 22.2-433) that are among the highest in the world. PBDE levels varied 100-fold. BDE-47 was the dominant PBDE congener, with levels exceeding the U.S.EPA Reference Dose (RfD) for neurodevelopmental toxicity (100 ng/kg/day) in most (60%) breast milk samples. In some samples, BDE-209 (2/82) and/or BDE-153 (5/82) were the dominant congeners, suggesting that BDE-209 can transfer to breast milk and/or break down in the mother and transfer to the nursing infant as the lower-brominated PBDEs associated with adverse effects. PBDE levels in California breast milk are approaching those of PCBs, and the trend PBDEs > PCBs may continue as PBDEs migrate from products to the indoor and outdoor environments.

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Background: Non-targeted Analysis (NTA) methods can identify novel exposures in a variety of biological matrices, however, few have been assessed for relationships with pregnancy complications. Objectives: This study characterizes levels of nine exogenous and endogenous chemicals including linear and branched isomers perfluorooctane sulfonate (PFOS); perfluorohexane sulfonate (PFHxS); monoethylhexyl phthalate; 4-nitrophenol; and tetraethylene glycol; the fatty acids: tridecanedioic acid and octadecanedioic acid, and the bile acid: deoxycholic acid. These chemicals were identified, selected, and confirmed in prior NTA steps and we evaluate their relationship with pregnancy complications in a diverse pregnancy cohort in San Francisco. Methods: Matched maternal and cord serum samples were collected from 302 pregnant people at delivery from the Chemicals in Our Bodies cohort in San Francisco. Chemicals were identified via NTA and quantified using targeted approaches. We calculate distributions and Spearman correlation coefficients testing the relationship of chemicals within and between the maternal and cord blood matrices. Among the maternal samples we used logistic regression to calculate the odds of gestational diabetes mellitus (GDM) and hypertensive disorders of pregnancy associated with prenatal chemical exposures. Results: We detected linear PFOS, PFHxS, tridecanedioic acid, and deoxycholic acid in at least 97% of maternal samples. We observed strong correlations between cord and maternal levels of PFHxS (coefficient = 0.9), linear PFOS (0.8), and branched PFOS (0.8). In maternal samples, branched PFOS was correlated with linear PFOS (0.8) and PFHxS (0.6). We found Linear PFOS and branched PFOS were positively associated with increased odds of GDM [OR (95%CI): 1.60 (0.94, 2.73) and 1.56 (1.00 , 2.44) respectively] and tridecanedioic acid was positively associated with hypertensive disorders of pregnancy [1.71 (0.79 , 3.82 )]. Discussion: Chemicals measured in this study were identified through NTA and targeted quantification. We identified endogenous and exogenous chemicals some of which have seldom been quantified in pregnant people.

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