24
Oct
Childhood, Prenatal Pesticide Exposure Impacts Immune System, According to Study
(Beyond Pesticides, October 24, 2025) A literature review published in Science of the Total Environment reports numerous peer-reviewed studies associating prenatal and childhood pesticide exposure to measurable alterations to children’s immune systems, including indicators of immunosuppression and increases in pro-inflammatory cytokines, among other adverse health effects. These immune system alterations are linked to higher infection risk and potentially contribute to autoimmune diseases and allergies later in life.
For over four decades, Beyond Pesticides has tracked the peer-reviewed science and identified a preponderance of evidence linking pesticide and chemical-dependent pest management to adverse human and ecological health effects. In this spirit, public health and environmental advocates continue to call for a wholesale transition to organic land management and organic pest management as biodiversity, public health, and climate crises continue to mount.
This mission supports the growth of the Parks for a Sustainable Future Program, where nineteen cities in eleven states across the country engage in pilot projects to transition parks, playing fields, and schoolyards to organic management practices and protect the health of children.
Background and Methodology
“This study aimed to evaluate the extent of immunotoxicity and correlation between exposure to pesticides and immune system alterations in children under five years of age, including exposure during pregnancy,†say the authors. Researchers used a Population-Exposure-Comparator-Outcome (PECO) framework to gather relevant studies for this systematic review and meta-analysis, employed in previous literature reviews.
- The populations are “infants and children up to 5 years of age; pregnant mothers (if placental transfer or tissue was investigated);
- The exposure assessed is “pesticide exposure during prenatal and/or early childhood [perinatal] periods (0-5 years), including exposure through maternal blood, placental transfer, or breastfeeding.â€
- The comparators within selected studies are “unexposed or low-exposure groups; mothers as comparators for their paired infants when applicable.â€
- The outcome of selected studies must include “[i]mmunotoxcitiy endpoints including immune system function measures (cytokine profiles, immune cell counts, immune cell activity) and biomarkers of immune dysfunction.â€
Studies were selected for analysis based on the following criteria:
- “original research published in peer-reviewed English language journals,
- observational and interventional research designs (cross-sectional, case-control, cohort studies, and RCTs) utilizing human biomonitoring to determine the prevalence, extent, and risk factors associated with immunotoxic pesticide exposure in children aged 0–5 years at [the] time of exposure, including maternal exposure during pregnancy when placental transfer was examined,
- and clear measurement of immunotoxicity markers.â€
Research that was excluded includes:
- “Laboratory studies (in vitro, in silico, animal models), case reports, opinion papers, commentaries, correspondence, review articles, published abstracts, and conference presentations,
- research focusing solely on pesticide toxicities without examining unintended immunological effects,
- studies lacking specific immunotoxicity endpoint measurements, and
- research primarily investigating allergic conditions, infectious diseases, or pediatric malignancies including leukemia and lymphoma.â€
Reviewers extracted data from the selected studies and employed Newcastle-Ottawa Scale (NOS) principles for assessing the quality of their methodologies. They tested this cross-sectional research on “six publications before implementation.” If two or more studies measured comparable health outcomes, the authors conducted meta-analyses based on the “random-effects model” to account for potential discrepancies across the diverse selection of studies. The review was also conducted using PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) 2020 guidelines and registered in PROSPERO, “an international systematic review registry that aims to promote transparency and open science, reduce reporting bias and help prevent unintended duplication and research waste.â€
The authors are researchers based in Egypt and the United Arab Emirates, including Benha University Departments of Anatomy and Embryology, Physiology, and Statistics; Central Clinical Pathology Labs in the Egyptian Ministry of Health, and the United Arab Emirates University’s Institute of Public Health. Several of the authors reported financial assistance through PathFinder Epidemiology Academy, Egypt; otherwise, all authors declared “no financial relationships with commercial interests.”
Results
“Prenatal exposure to organochlorine pesticides was associated with decreased lymphocyte counts, altered T-cell subpopulations, dysregulated cytokine production, and increased susceptibility to infections,†researchers conclude. They continue to summarize the main findings of their literature review: “Pesticide exposure was linked to both immunosuppression and pro-inflammatory/allergic responses, suggesting complex and potentially exposure-specific effects. This review provides evidence that prenatal and early childhood pesticide exposure is associated with measurable changes in immune system parameters.â€
Seventeen studies (eight cohort, seven cross-sectional, and two case-control) were selected after an initial 2,291 records. The studies were published between 2000 and 2021, with sample sizes ranging from 31 to 1,363 (median study size population was 198). Fourteen of the seventeen studies investigated prenatal exposure to various classes of pesticides, including organochlorines (fourteen studies), organophosphates (three studies), pyrethroids (two studies), and carbamates (one study). The immune parameters measured across the studies included hematological markers (ten studies), various lymphocyte subtypes (ten studies), pro- and anti-inflammatory cytokines (eight studies), immunoglobulins (four studies), functional outcomes (three studies), and clinical outcomes (two studies).
“Meta-analyses revealed significant reductions in neutrophil counts (effect size: −0.09, 95% CI: −0.17, −0.01; p = 0.02) and eosinophil counts (effect size: −0.06, 95% CI: −0.09, −0.03; p < 0.001),†according to the authors. The 95 percent confidence interval (95% CI) offers a parameter for measuring the likelihood that the associated finding (i.e., drop in neutrophil counts) is likely to be true 95 percent of the time. Additionally, a p-value of 0.02 means that there is likely a two percent chance of observing data proving the null hypothesis valid; in other words, there is a high likelihood that the observed results are not random. For neutrophils, the selected studies show an overall negative net effect with pesticide exposure. Neutrophils are considered “the first line of defense against bacterial infections.†(Segal, 2005) Meanwhile, a “reduction in eosinophils could have implications for allergic responses and parasite defense mechanisms.†The overall effect size was also negative, with a p-value representing a probability of one in a thousand that the observed data is due to random chance.
They continue: “Pro-inflammatory cytokine production was significantly increased (effect size: 0.18, 95% CI: 0.08, 0.28; p < 0.001).†In short, the overall effect is significant across the selected studies. Separately, organochlorines were associated with decreased lymphocyte counts, while a metabolite of DDT (p,p’-DDE) “was associated with increased lymphocyte [white blood cell] counts.†Additionally, exposures to a mixture of pesticides “showed elevated immunoglobulin responses.â€
Previous Research & Commentary
Advocates continue to sound the alarm and call for an organic transition, given the preponderance of evidence linking pesticide exposure to adverse health effects in children and childhood development.
A report by Environmental Working Group (EWG) in 2023 identified 200 hundred-foot pesticide spray “buffer zones†around 4,028 U.S. elementary schools contiguous to crop fields, emphasizing the disproportionate risks that U.S. children face to pesticide exposure. (See Daily News here.) Just this month, additional EWG analysis (see here) found that 24,471 public elementary and middle schools are located within a quarter mile of chemical-intensive cropfields. Meanwhile, recent research published in Environmental Science and Technology finds that there are 47 current-use pesticides—products with active ingredients that are currently registered with the U.S. Environmental Protection Agency (EPA)—detected in samples of indoor dust, drinking water, and urine from households in Indiana. (See Daily News here.)
Meanwhile, regulatory experts at Natural Resources Defense Council, Center Biological Diversity, and Center for Food Safety have pointed to serious flaws in the pesticide registration process at EPA with an in-depth evaluation of the agency’s failure to protect the public from the harmful effects of five neonicotinoid (neonic) insecticides—as mandated by the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), as amended by the Food Quality Protection Act (FQPA) of 1996. All five neonicotinoids evaluated—acetamiprid, clothianidin, imidacloprid, thiacloprid, and thiamethoxam—are associated with significant shrinkage of brain tissue at the highest dosage, according to U.S. Environmental Protection Agency (EPA) data reports. (See Daily News here.)
This is also an international crisis. A commentary published in Science of The Total Environment earlier this year showcases the occupational and environmental exposure pathways of fossil-fuel-based pesticide and fertilizer products that children across the globe face, particularly in rural areas of low- and middle-income countries. (See Daily News here.) Two decades after the introduction of genetically engineered, herbicide-tolerant crops and the consequential exponential growth in weed killers, Brazil has seen an increase in childhood cancer between 2004 and 2019. (See Daily News here.)
Researchers based in Spain found that children with higher levels of certain insecticide metabolites (chlorpyrifos, diazinon, general organophosphate, general pyrethroid metabolite, general organophosphate metabolite, and ethylene-bis-dithiocarbamate fungicides) are more likely to experience early puberty. (See Daily News here.) A study published in Antioxidants finds that prenatal and early life exposure, usually after birth (perinatal), to glyphosate-based herbicides (GBH) induces oxidative stress in the brain, causing damage and negatively affecting melatonin levels. This, in turn, can have developmental implications in the long term, as the disruption of melatonin levels also has implications for the development of age-associated neurodegenerative diseases, as melatonin is a neuroprotector against neurodegenerative diseases associated with aging. (See Daily News here.) Meanwhile, exposure to glyphosate and its breakdown products is associated with an increased risk of liver and metabolic disorders in children and young adults. (See Daily News here.) Another study published in 2022 in Toxicology and Applied Pharmacology came to a similar conclusion on perinatal exposure to glyphosate and perinatal liver damage. (See Daily News here.)
Call to Action
See Beyond Pesticides’ Eating with a Conscience tool, where you can select over 90 individual fruits, vegetables, and other whole foods and identify which combination of pesticide residues (and links to their associated health effects) are found in non-organic versions.
For discussion of eco-sensitive, health protective practices that are cost effective, consider attending Beyond Pesticides’ 42nd National Forum Series, The Pesticide Threat to Environmental Health: Advancing Holistic Solutions Aligned with Nature, which is scheduled to begin on October 29, 2025, 1:00-3:30pm (Eastern time, US) with a focus on aligning land management with nature in response to current chemical-intensive practices that pose a threat to health, biodiversity, and climate. The virtual Forum is free to all participants. 
 Register here.
Plus, take action here on organic bills that have recently been introduced in the first year of the 119th Session of Congress.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source: Science of the Total Environment
