Women exposed to agricultural pesticides, even before becoming pregnant, may be putting their newborn's health at risk. A new University of Arizona study links those exposures to poorer health in newborns, raising questions about how farming chemicals affect the next generation.
The study , published in the Journal of Exposure Science & Environmental Epidemiology, found that exposure during preconception to certain commonly applied pesticides – particularly those belonging to the classes of organophosphates, pyrethroids and carbamates – was associated with lower Apgar scores. This score a measure given to newborns within five minutes of birth and is strongly correlated with long-term health outcomes of the baby.
The multi-institutional study led by U of A included researchers from Harvard Chan School of Public Health and UCLA Fielding School of Public Health.
"Pesticides are designed to be toxic – very often, the biological mechanisms that they act on are present not just in insects and weeds, but also in humans. They have demonstrable biological effects on human health," said Melissa Furlong, an assistant professor at the Mel and Enid Zuckerman College of Public Health and the senior author of the study.
The research group analyzed pesticide use registries that consist of comprehensive records of every pesticide application made across the state. Arizona is one of the two states in the U.S. that maintain pesticide use registries. The registries include information such as crop type, pests, brand name and active ingredient of the pesticides used.
The team collected all birth certificate records in the state of Arizona and linked them to the Arizona pesticide registry. They found that exposure to certain classes of pesticides during preconception and pregnancy were associated with low Apgar scores, a unique metric that is predictive of certain neurological outcomes of newborns and is correlated with a baby's health through childhood.
"What's new in this study is that we identified the preconception period as a possible sensitive window of exposure to some of the commonly used pesticides," said Audrey Yang, a graduate student at the College of Medicine – Tucson and the study's first author.
Though the study found a strong correlation, it does not definitively state that pesticide exposure during preconception and pregnancy deteriorates the health of newborns. However, in the future, Furlong's group is planning to look at Medicaid records in the state of Arizona and see if this association pans out for actual neurodevelopmental disorders through childhood.
It is important to have more data on the health effects of specific ingredients in pesticides so that their application can be regulated in a way that will improve both maternal and child health, Furlong said. It's not like these ingredients are irreplaceable, she said, as almost every active ingredient has an alternative, and not all pesticides are equally toxic.
"I'm not suggesting a blanket ban on all pesticides. I'm just suggesting we do some more comprehensive legislative or policy initiatives for individual ingredients that exert the most harm," Furlong said.
On the clinical side, the study highlights the importance of sharing environmental history with doctors, Yang said.
"If you think you have increased pesticide exposure, I think it's a notable piece of information to share with your physician," Yang said.
With assistance from the Southwest Environmental Health Science Center , Furlong's group is doing outreach to clinicians by creating awareness about the health effects of pesticides, educating their patients living in agricultural areas with more exposure to pesticides, and encouraging pregnant women to avoid pesticide use during pregnancy.
Furlong shared a few recommendations to reduce pesticide load in households that are close to agricultural areas. Simple measures like vacuuming and dusting homes, using doormats and avoiding walking with shoes inside the house can lower the pesticide load. For those who use well water, it may be beneficial to use water filters. For those in agricultural areas, it is important to change air filters at least once a month during pesticide spray seasons.
Some agricultural pesticides are also designed for residential use to kill weeds and mosquitoes. Furlong recommended that people ensure that their products don't contain the ingredients beta-cyfluthrin, cypermethrin, esfenvalerate and fenpropathrin, as they were associated with lower Apgar scores in the study.
"Most importantly, try not to use indoor insecticides during pregnancy," Furlong said.
