19
Aug
Biomonitoring of Total Pesticide Exposure Shows Adverse Effects to Women’s Reproductive Health
(Beyond Pesticides, August 19, 2025) A new study from Argentina highlights the importance of applying the concept of the exposome (total exposures over lifetime) as a scientific framework, the value of biomonitoring, and findings of adverse pregnancy outcomes. The study documents the presence and effects of pesticides on maternal and fetal health during pregnancy. The results show that pregnant Argentine women are exposed to dozens of pesticides, and that certain mixtures of these chemicals are associated with harm to pregnancy outcomes, especially among rural women.
The exposome, the authors write, comprises the “non-genetic factors that may be involved in the development or aggravation of human disease. The prenatal exposome includes all environmental chemicals that the mother is exposed to during pregnancy (maternal exposome) and those chemicals that reach the placenta and fetus from the maternal circulation (fetal exposome).” The authors emphasize that understanding the exposome almost by definition requires studying mixtures of environmental chemicals rather than analyzing the effects of each in isolation.
The second important aspect of the study is its use of biomonitoring. The researchers analyzed urine samples from 90 pregnant women in various gestational stages from rural and urban regions of Argentina. The researchers also collected demographic information from the women, including education levels, agrochemical use, diet, smoking, and alcohol and drug use.
They tested the samples for 74 pesticides and found a total of 39. Eighty percent of the samples had detectable pesticides. Just over half of the pesticides were insecticides, about a third were fungicides, and nearly 18% were herbicides. Just over 60% are registered in Argentina; about 13% are unregistered, and a quarter of those found are banned there.
The fungicide vinclozolin, used in Argentina on fruits, vegetables, wine grapes, and chia plants (a type of Salvia), was the most frequently detected pesticide. This study reports the presence of vinclozolin for the first time in a biomonitoring study in Argentina. It is a possible human carcinogen also noted for its anti-androgenic effects, and thus is a factor in feminizing male animals. The second and third most common pesticides are the pre-emergent herbicide propazine, which is related to atrazine and used on ornamental plants in greenhouses, and the organophosphate insecticide and acaricide triazophos, which is applied to fruit and cereals. Both, also possibly carcinogenic to humans, have not been previously reported anywhere in maternal samples. Triazophos is banned in Argentina and the European Union. It is not registered in the U.S. and is being phased out in many regions. In all, a quarter of the pesticides detected in the current study are banned in Argentina, and this may be evidence not only of their continued use in some places, but also of their persistence in the environment. This highlights the extreme importance of both rapidly stopping the use of current highly toxic and persistent pesticides and preventing registration of new ones.
About two-thirds of the samples contained mixtures of the various pesticides detected, with a combination of fungicides and insecticides showing up in about a fifth of the samples and another fifth containing mixtures of herbicides, fungicides, and insecticides.
Regarding mixtures, the authors write, “When analyzing pregnancy outcomes in relation to the environmental exposome, it is essential to consider mixtures rather than individual pesticides. In this regard, we have found that samples from complicated pregnancies associated with fetal development had a higher number of pesticides.” Previous research has shown associations between the number of pesticides in cord blood and low birth weight, pesticide mixtures in maternal urine and smaller fetal head circumference, and multiple neonicotinoids in maternal urine and gestational diabetes.
There were few differences between the rural and urban women demographically, such as age, body mass index, education level, and diet. About half of the rural women reported using home insecticides during pregnancy compared to 39% of urban women. More rural women had mixtures of pesticides, but the researchers did not view the difference as striking. However, there were some important differences between the two groups.
Overall, about a third of the pregnancies were problematic, producing gestational hypertension, preeclampsia, gestational diabetes, and anemia in the women and preterm birth, intrauterine growth restriction (IUGR), low birth weight, and congenital anomalies in the fetuses. Here, the urban-rural divide was striking: nearly half the rural women had adverse pregnancy outcomes compared to 19% of the urban women, and fetal development and growth were more common complications for rural women. There is a strong association between IUGR and the number of pesticides in the women’s urine, as was the occurrence of triazole fungicides, particularly tebuconazole, in this group. Tebuconazole is a known reproductive toxicant. In vitro studies have shown that it interferes with certain cellular processes affecting placental and fetal development, and exposure to tebuconazole results in low birth weight and feminization of male fetuses in rats.
The authors suggest a number of reasons for the higher risk of adverse pregnancy outcomes among rural women. Rural women live closer to crop fields and thus may have additional exposures beyond those common to urban women as well. The authors write that “the exposome in rural areas may contribute to adverse health outcomes in pregnant women and fetuses.” Further, they note, there is much less access to health care, especially prenatal care, in rural areas.
The Argentinian study adds to the abundant evidence that pesticides harm women’s health, and women’s reproductive health in particular, as well as offspring at every stage of development. See Beyond Pesticides’ Birth/Fetal Effects section of our Pesticide-Induced Diseases database. This resource provides links to numerous studies detailing the effects on pregnancy of everything from malathion and chlorpyrifos to paraquat and imidacloprid.
While there are limitations to the current study, including a small sample size, the collection of only a single urine sample per participant, and a mixture of pregnancy phases among the women, it demonstrates the usefulness of biomonitoring as a means of expanding and deepening the scientific understanding of pesticides’ global impacts. The concept of the exposome is especially helpful because it acknowledges that no one is exposed to just one thing at a time, in one life stage, and that environmental exposures to a plethora of external influences are cumulative over a lifetime, beginning at conception and sometimes producing their harms decades after they occur. In particular, it is urgent that we get an accurate picture of how mixtures of pesticides affect biological systems. The outdated, ineffectual toxicological framework entrenched in pesticide regulation and supported by the pesticide industry must give way to a more realistic and precise means of assessing the true effects of pesticides.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Sources:
Pesticide exposure as prenatal exposome: A biomonitoring study in pregnant women from Argentina
Racca et al
Chemosphere 2025
https://pubmed.ncbi.nlm.nih.gov/40570729/
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https://beyondpesticides.org/dailynewsblog/2025/03/on-international-womens-day-elevated-pesticide-risks-to-womens-health-support-urgent-need-for-transition-to-organic/
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https://beyondpesticides.org/dailynewsblog/2025/02/exposure-to-glyphosate-herbicide-adversely-affects-neonatal-health-study-finds/
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Pesticide Exposure Contributes to Preterm Births and Low Birth Weight
Agrichemicals in surface water and birth defects in the United States
Winchester et al
Acta Paediatrica 2009
https://pmc.ncbi.nlm.nih.gov/articles/PMC2667895/?tool=pubmed
