Cumulative Chemical Exposures During Pregnancy and Early Development

Abstract

Industrial and consumer product chemicals are widely used, leading to ubiquitous human exposure to the most common classes. Because these chemicals may affect developmental milestones, exposures in pregnant women and developing fetuses are of particular interest. In this review, we discuss the prevalence of chemical exposures in pregnant women, the chemical class-specific relationships between maternal and fetal exposures, and the major sources of exposures for six chemical classes of concern: phthalates, phenols, perfluorinated compounds (PFCs), flame retardants, polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCs). Additionally, we describe the current efforts to characterize cumulative exposures to synthetic chemicals during pregnancy. We conclude by highlighting gaps in the literature and discussing possible applications of the findings to reduce the prevalence of cumulative exposures during pregnancy.

Environmental influences on reproductive health: the importance of chemical exposures

“…They are detected in the serum of 90–100% of pregnant women (3). One study examined the temporal changes in the levels of PFAS among California women over the past 50 years and found a significant drop of PFOS level from the 1960s to 2009, which is consistent with the phase-out of the perfluorooctyl manufacturing practice in the US in 2002 (36).…”

“…Two examples of these chemicals that are widely reported in biomonitoring studies are phenols, a type of carbolic acid and aromatic compounds including BPA, triclosan and parabens (3,50), and phthalates (51). In contrast to the persistent chemicals such as PFAS, where maternal concentrations across pregnancy are highly correlated (52), only low to moderate correlations were found between multiple measurements taken over pregnancy for less persistent chemicals such as BPA (53–55) and phthalate metabolites (55,56).…”

“…Phthalate metabolites are detected in over 90% of the maternal urine samples during pregnancy among North American or European populations (3). Yet, there are variations in the MEP levels across different studies and populations (Table 7).…”

“…Different pesticides have been associated with a range of reproductive and developmental outcomes including poorer birth outcomes, impaired cognitive and neurodevelopment, and childhood cancers (Table 1). Among pesticides, organochlorine pesticides (OCPs) such as hexachlorobenzene (HCB), dichlorodiphenyltrichloroethane (DDT), chlordane, and hexachlorocyclohexane (HCH) have been more widely studied, due to their earlier use and their persistent and bioaccumulative nature, endocrine disrupting properties, as well as their adverse health effects (3,64). Despite being banned in the US in the 1970s, some OCPs are still detected in US pregnant women (27).…”

“…Chemical exposures, especially during critical and sensitive windows of development such as pregnancy, can lead to a myriad of health consequences that can manifest across individual’s lifespan and potentially be transmitted to future generations (1,2). Chemical exposures that occur during pregnancy can cross the placenta and can accumulate in the fetus (3). Accordingly, the next generations are born “pre-polluted” (4) due to these pre-conception and pre-birth exposures.…”