A Critical Review on the Opportunity to Use Placenta and Innovative Biomonitoring Methods to Characterize the Prenatal Chemical Exposome

Adverse effects associated with chemical
exposures during pregnancy
include several developmental and reproductive disorders. However,
considering the tens of thousands of chemicals present on the market,
the effects of chemical mixtures on the developing fetus is still
likely underestimated. In this critical review, we discuss the potential
to apply innovative biomonitoring methods using high-resolution mass
spectrometry (HRMS) on placenta to improve the monitoring of chemical
exposure during pregnancy. The physiology of the placenta and its
relevance as a matrix for monitoring chemical exposures and their
effects on fetal health is first outlined. We then identify several
key parameters that require further investigations before placenta
can be used for large-scale monitoring in a robust manner. Most critical
is the need for standardization of placental sampling. Placenta is
a highly heterogeneous organ, and knowledge of the intraplacenta variability
of chemical composition is required to ensure unbiased and robust
interindividual comparisons. Other important variables include the
time of collection, the sex of the fetus, and mode of delivery. Finally,
we discuss the first applications of HRMS methods on the placenta
to decipher the chemical exposome and describe how the use of placenta
can complement biofluids collected on the mother or the fetus.