Vol. 24, Issue 2: Spring 2017

‘From Mother to Child: Measuring Prenatal Exposure to Analytes and Heavy Metals

Sasha Narain

More than 99 percent of pregnant women in the United States are exposed to harmful manufacturing chemicals, present in everyday products ranging from shampoos to furniture polish. Prenatal exposure to these compounds is known to have adverse effects on maternal hormones and neurological development of the fetus. A study conducted at the University of California, San Francisco and the University of California, Berkeley’s School of Public Health, analyzed the prevalence of these chemicals amongst urban populations of women, with an emphasis on Latina women. Researchers, lead by Rachel Morello-Frosch, aimed to characterize the prenatal exposures of a group seldom recognized in medical research and to measure the difference in concentration levels of heavy metals such as cadmium, mercury, and lead, between the mother and the fetus.

It is well known that prenatal exposure to manufacturing chemicals and heavy metals can have detrimental effects on the development of a fetus. The consequences of these exposures range from low birth weight and birth defects to delayed neurological development and cancer. More recently, the public health implications of heavy metal poisoning have come into question, as it did during the lead toxicity crisis in Flint, Michigan. Because heavy metal exposure has proven to be of a serious Public Health concern, it has spurred further public consequences such as increased demands on educational and correctional facilities. In order to mitigate these harms, the Environmental Protection Agency has issued orders against the production of polychlorinated biphenyls (PCB) in the United States, and required reporting of toxic substances used and released by cosmetic, pharmaceutical, and food companies. As such, the study reported that lower levels of bioaccumulating compounds have been recorded across populations in response to the increased regulation of these compounds. However, exposure to harmful chemicals remains a threat to many populations, especially in urban populations who face more frequent exposure. For example, PCBs are still found in old fluorescent lighting fixtures, plasticizers, and hydraulic fluids. Similarly, the improper disposal of many bioaccumulating compounds- compounds that cannot be flushed out of the body through normal biological processes and therefore, build up in body tissues- can contribute to why these levels are still observed today in adipose tissue today.

The differences in accumulation of certain compounds across fetal and uterine tissue depend on the compound’s ability to penetrate the uterine wall and duration of exposure to the compound. For example, cadmium was identified in a majority of participants’ maternal blood but not in any cord blood, while mercury and lead were found in near equal concentrations in maternal and cord blood. This process also speaks to the resulting diseases caused by these compounds and how they augment the development of the fetus.

Researchers acknowledge that levels of these compounds may fluctuate throughout pregnancy. However, the consequences of these exposures surpass the biological. These are societal concerns that implicate the health and success of the next generation. Taking small steps to reduce exposure to many of these compounds has an economic impact on public funds that will not be necessitated by raising a generation exposed to these compounds. This study not only demonstrates the passing of some of these chemicals across the placenta to the fetal environment but also shows the efficacy of laws regulating these chemicals as several chemicals that were once present in the environment were not detected in blood samples.