A concerning new study published in Environmental Health found that 99% of pregnant women had detectable levels of the weedkiller glyphosate in their urine during the first trimester. Glyphosate is the active ingredient in Roundup and many other herbicides used in agriculture and landscaping.
The researchers analyzed urine samples from 187 high-risk pregnant women attending a specialty obstetrics clinic in Indiana. Nearly all (186 out of 187) had glyphosate above the minimum detection level. The average urine concentration was 3.3 ng/mL, similar to a previous study of pregnant women in Indiana.
This shows that glyphosate exposure is extremely widespread in the US population. The high detection rate is likely due to the heavy use of glyphosate-based herbicides in industrial farming as well as home and garden use. Glyphosate residues are also frequently found in food and water.
The study then focused on the 155 pregnancies that resulted in live births. Higher maternal glyphosate levels in the first trimester were associated with lower newborn birth weight adjusted for gestational age. For every 1 ng/mL increase in mom’s glyphosate level, the baby’s birth weight percentile dropped by 3.2%.
This suggests that fetal growth may be impaired by early pregnancy exposure to glyphosate. The researchers say their findings are consistent with animal studies showing reduced fetal growth after glyphosate exposure. However, the human health impacts remain unclear and larger studies are needed.
Additionally, the infants of moms with higher glyphosate levels had a slightly elevated risk of being admitted to the neonatal intensive care unit (NICU).
The results raise concerns because early fetal development is a vulnerable window of exposure. Even small changes in fetal growth can have lasting health consequences. Preterm and low birth weight babies are at increased risk for developmental issues.
While an observational study like this cannot prove causation, it adds to the evidence that current levels of glyphosate exposure may not be safe for pregnant women and developing babies. More research is urgently needed given the widespread exposure. In the meantime, pregnant women may want to take precautions to limit their contact with glyphosate.
This highlights the need for regulatory agencies like the EPA to incorporate up-to-date human studies in their glyphosate risk assessments. So far only animal studies have been used to set safety standards. But considering glyphosate is now detected in almost every pregnant woman, as well as present in most food and water, a careful re-evaluation of its risks to human health is overdue.
