{"id":38082,"date":"2025-04-02T00:01:41","date_gmt":"2025-04-02T04:01:41","guid":{"rendered":"https:\/\/beyondpesticides.org\/dailynewsblog\/?p=38082"},"modified":"2025-07-24T14:47:42","modified_gmt":"2025-07-24T18:47:42","slug":"study-finds-reproductive-system-effects-in-adolescents-with-prenatal-pesticide-exposure","status":"publish","type":"post","link":"https:\/\/beyondpesticides.org\/dailynewsblog\/2025\/04\/study-finds-reproductive-system-effects-in-adolescents-with-prenatal-pesticide-exposure\/","title":{"rendered":"Study Finds Reproductive System Effects in Adolescents with Prenatal Pesticide Exposure"},"content":{"rendered":"

(Beyond Pesticides<\/em>, April 2, 2025) In examining prenatal residential proximity of documented pesticide spraying in California to the menstrual cycle characteristics of 273 Latina adolescents, researchers report in the American Journal of Epidemiology<\/em><\/a> a positive association between exposure to the insecticide methomyl<\/a> and heavy bleeding. Other pesticides appear to influence menstrual symptoms as well. \u201cAdolescents\u2019 menstrual cycle characteristics can be \u2018vital signs\u2019 of health and impact quality of life,\u201d the authors share. They continue, \u201cTo our knowledge, this is the first study to examine the association between prenatal pesticide exposure and menstrual outcomes in adolescents of any demographic group.\u201d<\/p>\n

Menstrual cycle characteristics, such as dysmenorrhea (painful or uncomfortable menstrual cramps), irregularity, and heavy menstrual bleeding, can also be indicators of underlying health conditions, including endometriosis, polycystic ovary syndrome (PCOS), thyroid dysfunction, and bleeding disorders. By associating the pesticide exposure of mothers during pregnancy to impacts on their children<\/a>, the researchers highlight important health risks for women and young girls that are often disregarded.<\/p>\n

\u201cThe prenatal period is a critical period of reproductive development that may be particularly sensitive to endocrine disruption<\/a>,\u201d the researchers share. As previously reported<\/a> by Beyond Pesticides, endocrine-disrupting chemicals are any synthetic or natural compounds that hinder endocrine system functions and create harmful effects on organisms, which includes many pesticides. The Endocrine Society<\/a> emphasizes, \u201cThere are nearly 85,000 man-made chemicals in the world, many of which people come into contact with every day. Only about one percent of them have been studied for safety; however, 1,000 or more of these chemicals may be EDCs [endocrine-disrupting chemicals] based on their probable endocrine-interfering properties.\u201d<\/p>\n

The authors of the article in American Journal of Epidemiology<\/em><\/a>, affiliated with the University of California Berkeley and San Francisco (particularly through the Center for Environmental Research and Community Health<\/a>), focus their research on California residents within the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) study. California represents an area of intensive cultivation, utilizing many agricultural pesticides, since the state \u201cgrows over a third of the United States\u2019 vegetables and over three-quarters of the country\u2019s fruits and nuts,\u201d according to the researchers.<\/p>\n

The study participants, with an average age of 16.3 years, were evaluated through a questionnaire regarding menstrual characteristics, including cycle length irregularities, painful menstruation, and heavy bleeding. These characteristics, in referencing their maternal residential addresses, were compared to California\u2019s Pesticide Use Reporting database to determine the association between prenatal residential proximity to 11 agricultural pesticides and any menstrual cycle symptoms. The chemicals were evaluated singularly and adjusted for co-exposure since \u201c[a]gricultural pesticide use practices often result in simultaneous and sequential exposure to multiple highly correlated active ingredients from different classes,\u201d the authors state.<\/p>\n

The pesticides included in the study are from six different pesticide classes. \u201cThese active ingredients were permethrin<\/a> [pyrethroid insecticide], methomyl<\/a> [carbamate insecticide], imidacloprid<\/a> [neonicotinoid insecticide], maneb<\/a>\/mancozeb<\/a> [ethylenebisdithiocarbamate (EBDC) fungicides], and glyphosate<\/a> [herbicide]. For the organophosphate insecticides, multiple active ingredients met our inclusion criteria: acephate<\/a>, chlorpyrifos<\/a>, diazinon<\/a>, malathion<\/a>, oxydemeton-methyl, and dimethoate<\/a>,\u201d the researchers note.<\/p>\n

As a result, the authors report, \u201cWe found evidence that prenatal exposure to endocrine-disrupting pesticides may impact certain adolescent menstrual cycle characteristics.\u201d The most notable association in the single exposure model is that a 2-fold increase in prenatal methomyl exposure correlates to a 29% increase in heavy menstrual flow. The researchers share that this relationship also \u201capproached statistical significance in our joint exposure model.\u201d<\/p>\n

They continue, \u201cOther instances where results approached statistical significance in joint exposure models were: permethrin exposure and increased odds of painful cycles [and] oxydemeton-methyl [organothiophosphate insecticide] exposure and increased odds of pain medication use during cycles.\u201d These findings suggest prenatal pesticide exposure is associated with subsequent menstrual cycle symptoms in children.<\/p>\n

As the authors point out, these symptoms can have a strong negative impact on individuals’ quality of life and mental health. One study<\/a> from Australia reports that teens with menstrual problems have significantly lower quality of life scores than healthy teens. Additional studies find that dysmenorrhea (painful or uncomfortable menstrual cramps) is \u201cpositively associated with academic absenteeism, depression, body image issues, and social isolation.\u201d (See studies here<\/a>, here<\/a>, here<\/a>, here<\/a>, and here<\/a>.) Symptoms that include heavy and prolonged menstrual bleeding can also be markers of bleeding disorders, interfere with mental and physical health, and lead to anemia and period-related stress. (See here<\/a> and here<\/a>.)<\/p>\n

\u201cMany currently used pesticides contain active ingredients that are known or suspected endocrine-disrupting chemicals (EDCs), which may interact with the endocrine system, preventing proper function by mimicking or blocking hormonal interactions,\u201d the researchers note. Within the study, evidence of endocrine disruption<\/a> in scientific literature is shared, including:<\/p>\n