Measurement of Agricultural and Dietary Glyphosate Exposure Among Pregnant Women

This study focuses on human exposure to glyphosate, the single most commonly applied agricultural chemical in the world. Glyphosate is an herbicide, and is most commonly known as the active ingredient in "Round Up". Glyphosate has been declared a probable human carcinogen by the International Agency for Research on Cancer and multiple toxicological studies have further suggested potential neurological and developmental effects of glyphosate exposure at environmentally-relevant levels. However, despite its extensive use, frequent presence in food and environmental media, and potential toxicity, current exposure levels in human populations are not well documented. This study aims to assess glyphosate exposure among a cohort of pregnant women and to quantify the relative contribution of agricultural and dietary sources of this exposure. A cohort of 40 pregnant women will be recruited from urban areas >10 miles from the nearest glyphosate-treated field and agricultural areas <1 mile from the nearest glyphosate-treated field. Weekly urine samples collected from these women throughout their pregnancies will be used to analyze glyphosate exposure. These same 40 participants will also take part in a two week-long randomized cross-over design dietary intervention, during which participants will receive one week of exclusively organic food (grown without the use of synthetic pesticides, including glyphosate) and one week of exclusively conventional food, in random order. During the intervention, the researchers will collect daily spot urine samples from each participant to analyze glyphosate exposure related to diet. The researchers hypothesize that during the time of year when glyphosate is actively applied, women living near glyphosate-treated fields will have higher exposures than those living further away. They also hypothesize that glyphosate exposure will be reduced among participants during randomization to the organic diet, but that this decrease will be larger among urban women than among those living near glyphosate-treated fields. The researchers have taken extra precautions to eliminate all COVID-specific risks. There will be no face-to-face contact between research staff and study participants throughout the entire study. Interactions between researchers and study participants will take place through videos, emails, texts, and/or phone calls. All urine samples will be left for researchers to pick up at a predetermined location and time, and all groceries will be delivered to participants' home and left at their front door.

Inclusion criteria

• Be in the first trimester of pregnancy
• No diagnosis of gestational diabetes or other high risk pregnancy factors
• Consume an exclusively conventional diet with no intentions to switch to an organic diet
• Agree to refrain from applying residential glyphosate (Round Up) during the study
• Either live more than 10 miles or less than 1 mile from a glyphosate treated field

Exclusion criteria

• Occupational exposure to glyphosate, or live in a household with an individual with occupational glyphosate exposure