«Investigating potential fetal exposure to antidepressants.» (sciencedaily.com)
Because DDT can pass to the child through the placenta, the blood of the mothers, collected shortly before or after birth, served as a proxy for fetal exposure. (scientificamerican.com)
To know whether fetal exposure to BPA is producing breast cancer in humans, you have to collect blood from the mother and the newborn, bank it, and follow that cohort for many, many decades. (discovermagazine.com)