28
Jul
Pesticide Effects on Enzymes, Oxidative Stress, and Cell Damage in Newborns and Mothers, Study Finds
(Beyond Pesticides, July 28, 2026) In a study published in Science of The Total Environment, researchers at the Federal University of Paraná in Brazil link pesticide exposure during pregnancy, particularly involving organophosphate and carbamate insecticides, with oxidative stress, which causes cell damage, and adverse health effects in both mothers and their newborns. In analyzing enzyme activity and biomarkers in samples of maternal peripheral (circulating) blood and umbilical cord blood from mother and newborn pairs, the data shows altered levels in both.
“The findings suggest relevant biochemical alterations in the maternal–newborn dyad, involving cholinesterase inhibition and oxidative imbalance,” the authors state. Notably, the enzyme acetylcholinesterase (AChE) is inhibited in 96% of umbilical cord blood samples and the oxidative stress biomarker 8-OHGua is elevated in both mothers and newborns, indicating oxidative DNA damage.
While many studies report associations between environmental pesticide exposure during pregnancy and alterations in fetal development, there are still many data gaps regarding indirect biomarkers of chronic pesticide exposure in pregnant women and newborns that this study addresses. “Considering the regional context of constant environmental pesticide exposure in this population, the present study aimed to assess cholinesterase activity as an indirect biomarker of exposure to cholinesterase-inhibiting pesticides and oxidative metabolism imbalance in maternal peripheral blood and umbilical cord blood from individuals living in an agricultural region of southern Brazil,” the researchers summarize.
Study Background
Organophosphates and carbamates, as the researchers describe, “represent a serious global public health issue” and are among the most commonly used insecticides in Brazil, accounting for “39.1% of poisoning cases recorded in the western region of Paraná between 2015 and 2017.” Those who work and live in areas with extensive chemical-intensive agricultural activity face disproportionate health risks from chronic pesticide exposure, as documented by a wide body of scientific literature. (See examples here, here, here, here, here, here, and here.) Many studies have also documented the ability of pesticides to cross the placental barrier, leading to alterations in embryonic and fetal development. (See studies here and here, as well as related Daily News coverage here, here, and here.)
Prenatal exposure to organophosphates and carbamates is associated with the inhibition of cholinesterase enzymes, which are vital enzymes that break down the neurotransmitter acetylcholine and help to regulate nerve signals. This includes AChE and butyrylcholinesterase (BChE). “Reduced activity of these enzymes is widely used as an indirect biomarker of exposure to cholinesterase-inhibiting compounds,” the authors note. “In addition, some studies have reported associations between decreased cholinesterase activity and adverse neonatal and developmental outcomes, including preterm birth, low birth weight, and neurobehavioral alterations.” (See here and here.)
The alteration of enzymes associated with pesticide exposure occurs through mechanisms of oxidative stress, which induces the generation of free radicals and causes alterations in the antioxidant enzymatic system. Research shows that when biomolecules are damaged through this mechanism, it “can trigger enzyme inactivation, accumulation of genetic alterations in DNA, membrane disruption, and increased atherogenicity [development of atherosclerosis] of plasma low-density lipoproteins.”
Methodology and Results
Ninety-eight pregnant women in their third trimester were recruited for the study between May and October 2023. The region in southern Brazil is an area where “pesticides are applied aerially or terrestrially on corn, wheat, and soybean crops for several months of the year, increasing the population’s exposure to these compounds.” From the 98 pregnant women who entered the study, blood samples were collected during birth, including “79 complete maternal–umbilical cord blood pairs, four isolated umbilical cord samples, and 15 isolated maternal samples.” The umbilical cord blood from the newborns was collected immediately after delivery, while the maternal venous blood from the placenta and circulating to the heart and lungs was collected either shortly before or immediately after delivery.
After analyzing the blood samples, the results reveal that 96% of umbilical cord blood samples and 45% of maternal blood samples have altered AChE enzymatic activity, with the lower values in newborns. As the authors report, “[T]he marked reduction in AChE activity observed in umbilical cord blood represents one of the most consistent findings of the present study and may reflect exposure to compounds capable of inhibiting cholinesterase activity during pregnancy.”
In analyzing biomarkers of oxidative stress, including the 8-OHGua marker, the researchers find additional alterations. The levels of 8-OHGua, which indicate oxidative DNA damage, show alterations in 87% of maternal samples and 90% of umbilical cord samples. The authors note: “[A]longside the genetic damage indicated by elevated 8-OHGua levels, other oxidative stress biomarkers also exhibited significant alterations. MDA [the toxic molecule, malondialdehyde] levels, a classical marker of lipid peroxidation, were elevated in maternal samples, exceeding reference values by 17%.”
Glutathione S-transferase (GST) activity is altered in both maternal and umbilical cord blood samples at a higher frequency for the cord blood (65%) than in maternal samples (54%). The researchers explain, “Although the expression of these enzymes is generally induced in response to the presence of xenobiotics (foreign substances) to enhance cellular tolerance, the observed reduction in GST activity may indicate a state of exacerbated oxidative stress, toxic overload, or impairment of cellular defense mechanisms.” (See research here.)
While this study acknowledges limitations in quantifying pesticide residues in blood and directly correlating it with the observed oxidative DNA damage, the results suggest patterns of association between altered maternal and neonatal biomarkers and pesticide exposure in a chemical-intensive region. The authors conclude: “This study is among the few Brazilian investigations to evaluate important indirect biomarkers related to cholinesterase activity and oxidative stress in pregnant women and neonates potentially exposed to cholinesterase-inhibiting compounds, such as organophosphates and carbamates… Considering the limited number of Brazilian studies addressing the relationship between environmental pesticide exposure and oxidative damage in the mother–child dyad, this study provides novel contributions to the fields of environmental health and reproductive toxicology.”
Previous Research
There is a preponderance of evidence linking pesticide exposure to deleterious health effects in infants and children. Exposure prior to birth and within the first few years of life are considered particularly hazardous as these “windows of vulnerability†are crucial for development. As shared in Daily News UNICEF Report Raises Alarm About Adverse Effects of Pesticides on Children’s Health: “Around the world, children are born into a landscape where the doubling of pesticide use since 1990 has made these chemical substances ubiquitous in our soil and food,†said George Laryea-Adjei, PhD, UNICEF Global Program Division Director at the release of a new report—Underestimated and Overlooked: The Silent Impact of Pesticides on Children—published through an initiative of the United Nations Children’s Fund. This report identifies the failure of existing regulatory structures to ensure basic protections and cites scientific evidence, investigative reporting, and litigation, concluding that synthetic pesticides are inconsistent with sustainability and human health.
Additional Daily News reports on a study of birth outcomes in Arizona, published in the Journal of Exposure Science & Environmental Epidemiology, where researchers find that preconception and prenatal exposure to certain carbamates, organophosphates, and pyrethroids increases the risk of lower Apgar scores, a metric used to assess neonatal health at one minute and ï¬ve minutes after birth. The results reveal that exposure to “several pesticide active ingredients at any point during preconception and/or pregnancy were associated with increased odds of low Apgar scores: the carbamates carbaryl and formetanate hydrochloride; the organophosphates diazinon and tribufos; and the pyrethroid cypermethrin.†Â
A 2021 study from the University of California San Francisco (UCSF), published in Environmental Science & Technology, finds over 100 chemicals present in U.S. pregnant women’s blood and umbilical cord samples. Many known environmental pollutants (e.g., heavy metals, polychlorinated biphenyl, and pesticides) are chemicals that can move from the mother to the developing fetus at higher exposure rates. Hence, prenatal exposure to these chemicals may increase the prevalence of birth-related health consequences like natal abnormalities and learning/developmental disabilities. (See Daily News here, as well as the Daily News archive related to children for more coverage.)
Beyond Pesticides’ Resources
Learn more about the Hazards of Pesticides for Children’s Health and why Children and Pesticides Don’t Mix. The Pesticide-Induced Diseases Database facilitates access to epidemiologic and laboratory studies based on real-world exposure scenarios that link numerous categories of public health effects to pesticides while the Gateway on Pesticide Hazards and Safe Pest Management provides information on specific pesticide active ingredients, as well as alternatives.
Make The Safer Choice and avoid hazardous home, garden, community, and food use pesticides to protect you and your family. Start by Eating with a Conscience and choosing organic food to protect not only health but the environment. Beyond Pesticides’ offers tips on Buying Organic Products (on a budget!) or you can Grow Your Own Organic Food. Be part of the organic solution by helping to transition to a pesticide-free world and support Beyond Pesticides’ mission by becoming a member or giving today!
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source:
Ródio, G. et al. (2026) Oxidative damage and cholinesterase activity in maternal and umbilical cord blood from an agricultural region in southern Brazil, Science of The Total Environment. Available at: https://www.sciencedirect.com/science/article/pii/S0048969726006625.
