Nitrate in drinking water linked to preterm birth rates, reports research

The author points out that the data is limited in scope, focusing only on one state. More recent data, as well as data from additional states and sources, such as private well water, could improve the strength of the association.

“Our work adds to the evidence base that the current regulatory threshold (> 10mg/L) may be insufficient for protecting the in utero transmission of water-based nitrate during the first trimester of pregnancy,” Semprini says. He concludes that current standards, unchanged since 1992, may need to be revisited as nitrate levels in groundwater continue to rise across the U.S.

He adds: "There is no safe level of prenatal nitrate exposure,” and goes on to state: "[t]he estimated impact from prenatal exposure to nitrates reflects 15% of the harm from prenatal exposure to smoking cigarettes. I do not want to diminish the importance of efforts to prevent smoking during pregnancy...but, I must ask, do we give nitrates 15% of the attention we give to smoking?”

Semprini also notes: "The regulatory threshold for nitrates in public water does not consider prenatal exposure and has not been updated since established in 1992. Ignoring the potential harm from lower levels of prenatal nitrate exposure, the current regulatory standards are not adequately protecting America's mothers or children."

Reference:

Jason Semprini, Early prenatal nitrate exposure and birth outcomes: A study of Iowa’s public drinking water (1970–1988), PLOS Water, https://doi.org/10.1371/journal.pwat.0000329.