Exposure to chemicals during fetal development can increase the risk of adverse health children’s health impacts. . While biomonitoring studies suggest pregnant women are exposed to chemicals, little is known about the extent of multiple chemicals exposures among pregnant women in the United States. Only about 300 of many thousands of environmental chemicals used in commerce are currently being bio-monitored by the U.S. Centers for Disease Control and Prevention (CDC). This talk will present research findings using a new analytic technique using time-of-flight liquid chromatography/mass spectrometry (TOF LC-MS), which provides a more systematic, agnostic, and comprehensive approach to assess cumulative exposure to environmental chemicals. We use this methodology to identify, previously unmeasured, chemicals in pregnant women from Northern California. The TOF LC-MS and will give will give us unprecedented insights into cumulative fetal exposure to environmental chemicals. In addition, the presentation will discuss the results of a new methodology to synthesize the available science to provide a concise, evidence-based description of the strength of the evidence on the relationship between chemical exposures and adverse health outcomes, presenting results for PFOA and birth weight as a case study.