Canadian pregnancy cohort maps POP levels in blood
MIREC found many POPs in maternal plasma but few in cord blood; parity, age, fish, and birthplace predicted levels.
Source
Concentrations of persistent organic pollutants in maternal and cord blood from the maternal-infant research on environmental chemicals (MIREC) cohort study
Study at a glance
- Design
- Cohort — MIREC pregnancy cohort measuring POPs/PFAS in maternal and cord plasma
- N
- N=1983 · 1,983 pregnant women in 10 Canadian cities (2008–2011)
- Population
- Canadian pregnant women and newborns in MIREC
- Outcome
- Maternal and cord POP/PFAS concentrations and demographic correlates
Structured fields used in claim comparison tables when every cited study has a complete layer.
What they did
The MIREC pregnancy cohort measured PCBs, organochlorine pesticides, PBDEs, and PFASs in first-trimester maternal plasma and cord plasma from women recruited in 10 Canadian cities (2008–2011), then related concentrations to demographic and diet covariates.
What they found
Among 1983 pregnant women, PFOS had the highest maternal PFAS geometric mean (4.56 μg/L). Maternal PFOA was four times higher than cord PFOA (1.65 vs 0.35 μg/L). Median detections were 14 POPs in maternal plasma versus 2 in cord plasma. Parity lowered most residues; fish eaters and foreign-born mothers had higher OCs/PCBs; 2011 samples were lower than 2008.
The limits
What it doesn't show
MIREC is a convenience sample of relatively educated, Canadian-born women, so it is not a random national snapshot. Cord:maternal ratios are only for pairs both above the LOD. The paper reports concentrations and predictors, not clinical health outcomes.
Key terms
- POPs
- Persistent organic pollutants that resist degradation and bioaccumulate, including PCBs, OC pesticides, PBDEs, and PFASs.
- MIREC
- Maternal-Infant Research on Environmental Chemicals, a Canadian pregnancy cohort of about 2000 women.
- Cord:maternal ratio
- Paired cord divided by maternal concentration; lipid-adjusted medians were 0.60–0.87 versus 0.08–0.28 unadjusted.
- PFAS
- Perfluoroalkyl substances; PFOS, PFOA, and PFHxS were the main detected compounds and transferred to cord plasma more often than PCBs.
- Parity
- Number of prior pregnancies; higher parity was associated with lower maternal POP concentrations.
Flashcards
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Quiz yourself
The highest maternal PFAS geometric mean in MIREC was:
Common questions
Were POPs higher in mothers or in cord blood?
Maternal plasma had far higher detection rates; cord plasma often had few or undetectable PCBs and PBDEs.
Which PFAS was highest in mothers?
PFOS, geometric mean 4.56 μg/L.
Did fish raise all chemical classes?
Fish consumers had higher levels of nearly all POPs except the PFASs.
Were first-trimester PFASs usable as exposure markers?
Yes: 1st and 3rd trimester PFASs were highly correlated (ICCs 0.6–0.8), with first-trimester values higher.
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