Food Contaminants
prenatal organophosphate exposure decreases child IQ
In plain terms: Does pesticide exposure in pregnancy lower a child's IQ?
Leans support Food Contaminants 🔬 Includes disconfirming
Part of: 🔍 pesticides in food
RefutedContestedStrong support
consensus score 0.32
In farming communities with high exposure, the evidence points that way. In European populations at ordinary dietary exposure levels, studies come back null. Some headline findings turn out to be about flame retardants, not pesticides.
📅 Last reviewed: 2026-07-29 ⓘ
Evidence ladder
How far up the ladder this claim has climbed. A high consensus on a low rung means "consistent so far," not "proven in people."
Top evidence so far: All trials, pooled (Meta-analysis)
MechanismIn-vitroAnimalObservationalRCTMeta-analysis
How the studies fall
6 support 2 contradict 0 tested null 10 mixed · 18 sources, 8 independent groups
What the evidence shows
The two largest syntheses lean toward a real adverse effect on childhood cognition, but the evidence is messier than the headline count suggests. The flagship pooled analysis is driven mainly by ONE cohort, a Californian farmworker community, which also appears separately in the literature, so the apparent replication is thinner than it looks.
The evidence (18)
| Source | Grade | Stance | Quality | Finding |
|---|---|---|---|---|
| Muñoz-Quezada MT et al 2025 · preprint | observational | mixed | moderate | Systematic review of 34 human studies (9 cohorts, 4 low risk of bias, ROBINS-E) on SIMULTANEOUS OP+pyrethroid co-exposure (mixed-compound, mixed-route/age, not OP-isolated) and brain health, 2014-2024; only 3 cohort studies specifically lin |
| Conejo-Bolaños LD et al 2024 · study_type: observational | observational | contradicts | low | Costa Rica ISA birth cohort, n=355 women, PRENATAL urine (1-3x in pregnancy), BSID-III at 1 year, adjusted for maternal education/parity/sex/HOME-score: chlorpyrifos metabolite TCPy per 10-fold increase showed a negative but non-significant |
| González-Alzaga B et al 2014 · Toxicology letters | observational | supports | moderate | Systematic review of 20 human studies (7 prenatal-only, through Dec-2012) on PRENATAL/postnatal OP pesticide exposure; most prenatal-exposure studies found negative effects on mental development and more attention problems in preschool/scho |
| Oskar S et al 2024 · study_type: observational | observational | mixed | low | High-risk US cohort, n=130 (public-use data, 2007-2014), PRENATAL urine (2nd/3rd trimester), Mullen Scales at age 3, 6-chemical Bayesian mixture model (parabens+BPA+TCPy+3-PBA): third-trimester TCPy (chlorpyrifos metabolite) was associated |
| Sapbamrer R et al 2019 · Environmental science and pollution research international | observational | supports | moderate | Systematic review of 50 human studies (1973-2019) on PRENATAL/postnatal OP pesticide exposure and neurodevelopment across neonate-to-school-age; 45/50 found an association, with prenatal exposure (15 studies, neonates/infants) more consiste |
| Wang A et al 2023 · Environmental health perspectives | observational | mixed | moderate | Wuhan cohort, n=3,123 urine samples/1,041 children, PRENATAL (3 trimesters), Bayley MDI/PDI at 2 years, adjusted models: two OP-pesticide metabolites (TCPy, 4-nitrophenol) per unit ln-increase were associated with lower boys' MDI (beta=-3.1 |
| Mou Y et al 2026 · study_type: observational | observational | mixed | low | Generation R cohort (Netherlands), n=565 prenatal / 539 age-5 samples, mixed EDC exposure (10 phthalates+BPA+5 nonspecific OP-pesticide metabolites, PRENATAL urine, 3x pregnancy), Wechsler subtests (verbal comprehension, matrix reasoning) a |
| Normann SS et al 2024 · Neurotoxicology and teratology | observational | mixed | moderate | Odense Child Cohort, Denmark, n=812 (low, mainly dietary exposure), PRENATAL urine at gestational week 28, abbreviated WISC-V FSIQ at age 7: maternal urinary TCPy (chlorpyrifos metabolite) reached significance only at mid-level exposure (no |
| Engel SM et al 2016 · Environmental health perspectives | observational | mixed | moderate | Pooled individual-participant analysis of FOUR US birth cohorts (n=936) -- author list confirms this includes the CHAMACOS California-farmworker cohort plus Mount-Sinai and Columbia-CCCEH NYC cohorts -- PRENATAL urine SigmaDAP/SigmaDEP/Sigm |
| Alqudaimi M et al 2026 · study_type: observational | observational | supports | moderate | Meta-analysis of 46 articles (25,975 participants, human studies through 10-Apr-2025, Web of Science/PubMed/EBSCOhost/Cochrane): PRENATAL OP exposure was significantly associated with decreased children's cognition overall, strongest in Asi |
| Coleman B et al 2025 · study_type: observational | observational | mixed | moderate | Systematic review of 31 LMIC studies (11 countries), including 10 with PRENATAL maternal measurements; explicitly notes 'few studies found adverse associations with urine/serum organophosphate levels' specifically, while organochlorines/car |
| Stein LJ et al 2016 · Neurotoxicology | observational | supports | moderate | CHAMACOS cohort (California farmworker community), n=329, PRENATAL urinary DAP metabolites (2 pregnancy samples, averaged), WISC-IV Full-Scale IQ at age 7: the adverse OP-IQ association was present and POTENTIATED by childhood adversity, st |
| Peterson BS et al 2025 · study_type: observational | observational | supports | moderate | Columbia Center for Children's Environmental Health (CCCEH) cohort, northern Manhattan/South Bronx NYC, n=270 of 512 with PRENATAL chlorpyrifos measured at delivery (imaged ages 6-14.7y): progressively higher prenatal chlorpyrifos was assoc |
| Biosca-Brull J et al 2026 · study_type: animal | animal | mixed | low | Mouse model (C57BL/6J + human-APOE e3/e4 knock-in), PRENATAL (EXPERIMENTAL ANIMAL) oral chlorpyrifos 1mg/kg/day gestational day 12-18 (dose vs. human dietary exposure not stated in abstract): CPF impaired long-term spatial-memory retention TEMPERED: preclinical (animal/in-vitro) evidence, retained in the ledger but not carrying a human-outcome headline; dosing is typically far above human exposure. |
| Cartier C et al 2016 · study_type: observational | observational | contradicts | moderate | PELAGIE mother-child cohort, France, n=231, PRENATAL urine collected <19 weeks' gestation, WISC-IV at age 6: WISC-IV scores showed NO significant association with prenatal (or childhood) total DAP metabolites -- a clean null for the prenata |
| Goodman CV et al 2023 · study_type: meta-analysis | meta-analysis | supports | moderate | Sex-specific meta-analysis (20 of 51 systematic-review studies pooled, screened through Dec-2021) of 6 developmental neurotoxicants incl. organophosphate pesticides (OPPs), each requiring an individualized PRENATAL/early-life biomarker: pre |
| Fu D et al 2026 · study_type: observational | observational | mixed | moderate | Shanghai Birth Cohort, n=502 mother-child pairs, PRENATAL urinary metabolites (1st/2nd trimester), WPPSI-IV IQ at age 4, adjusted models: the significant IQ signal (FSIQ -0.90pts, 95%CI -1.62,-0.19 per log2 DPHP) is driven by diphenyl phosp |
| Juntarawijit Y et al 2021 · preprint | observational | mixed | low | Thailand case-control, 442 developmental-delay cases vs 413 controls (children <5y); exposure was MATERNAL SELF-REPORT of pesticide use (not urinary metabolite, so route/methodology mismatches claim scope), and the only statistically signif |
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