U-M study: Exposure to common herbicides linked to premature births Chemicals found in widely used herbicides like Roundup may cause preterm births Tags: A new study from the University of Michigan has found a connection between exposure to widely used herbicides and premature births. The University of Michigan conducted a nested case-control study among a cohort of pregnant women in northern Puerto Rico that examined the connection between exposure to a chemical found in herbicides and preterm births as part of ongoing research of contamination threats. The study, published Wednesday, found that women in the later months of their pregnancy had an increased risk for premature birth if exposed to the chemical glyphosate, which is found in weed killer Roundup and other herbicides.