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Once again a study finds that pesticide exposure is linked to an adverse health effect - that pesticide exposure in the home during pregnancy and early childhood is linked to an elevated risk of brain tumor in the child. Other studies have also found that pesticides used in the home are associated with a higher risk of childhood cancers.

This is because pesticides do cross the placental barrier, as the study researchers point out: "There is evidence that pesticides cross the fetal-placental barrier since residues of some insecticides have been found in umbilical cord blood, neonatal hair, and meconium following maternal exposure during pregnancy." Also, the International Agency for Research on Cancer (IARC) has classified "more than twenty pesticide chemical compounds as potential human carcinogens".

The following are examples (but there are more) of other studies finding pesticide and childhood cancer links: A meta-analysis published in 2015 in Pediatrics by researchers at Harvard University found that children exposed to indoor insecticides (also herbicides) have a higher risk of certain childhood cancers, specifically leukemia, lymphomas, and brain tumors. A 2013 study published in Cancer Causes and Control found that professional pest control applications in the home within a year of conception and during pregnancy was associated with a higher risk of childhood brain tumors. A review of studies published in 2010 found that pesticide exposure during pregnancy and childhood increased the risk of childhood leukemia.

The good news is that there are alternatives to exposing fetuses and children to toxic pesticides at home - by using alternative ways of dealing with pests, such as least toxic Integrated Pest Management (IPM) or organic methods. That means doing other things (such as sealing or caulking holes, putting out traps and baits, vacuuming), a focus on least toxic methods and on prevention (here and here), rather than routinely applying toxic pesticides. If needed, least toxic pesticides include boric acid and vinegar. Other sources of pesticide exposure for pregnant women and children are foods and exposure in settings outside the home - perhaps even a friend's yard. By the way, pesticide exposure for everyone is linked to a higher risk of health problems, not just pregnant women and children.

From Science Daily: Pesticide use during pregnancy linked to increased risk of childhood brain tumors

Previous epidemiological studies have suggested that exposure to pesticides during pregnancy may have a possible role in the development of childhood brain tumors. In a new International Journal of Cancer analysis, researchers found a link between maternal residential pesticide use -- particularly insecticides -- and the risk of childhood brain tumorsThe analysis included 437 malignant childhood brain tumor cases and 3102 controls from two French studies. Pesticide use was associated with a 1.4-times increased risk of childhood brain tumors.

The investigators noted that many pesticide compounds are classified as probable carcinogens, and there is evidence that some insecticides can pass through the feto-placental barrier. "Although such retrospective studies cannot identify specific chemicals used or quantify the exposure, our findings add another reason to advise mothers to limit their exposure to pesticides around the time of pregnancy," said Nicolas Vidart d'Egurbide Bagazgoïtia, lead author of the study. [Original study.]

  Children exposed to insecticides (pesticides) at home have an increased risk of developing leukemia or lymphoma, a new review finds.The analysis, of 16 studies done since the 1990s, found that children exposed to indoor insecticides had an elevated risk of developing the blood cancers. There was also a weaker link between exposure to weed killers and the risk of leukemia. There is also evidence from studies linking pesticides with neurological consequences, such as lower IQ and attention deficit hyperactivity disorder.Note: insecticides and weed-killers (herbicides) are both pesticides. The article also gives some non-chemical approaches to treating pests with non-chemical means. From CNN:

Report: Pesticide exposure linked to childhood cancer and lower IQ

Pesticide use in homes may increase the risk of children developing leukemia or lymphoma, a new report suggests. Researchers combined data from 16 earlier studies that had compared pesticide exposure between children who developed leukemia or lymphoma and those who did not. These studies estimated the level of insecticides and herbicides both inside the home and in the yard and outdoor residential space.

The researchers concluded that children who had been exposed to insecticides indoors were 47% more likely to have leukemia and 43% more likely to have lymphoma. Although leukemia and lymphoma are rare -- leukemia affects about five in 100,000 children in the United States -- they are among the common types of childhood cancers. "Childhood cancers are increasing year by year in this country....

This analysis "is confirming that pesticides may play a role, possibly a significant role, in the development of childhood leukemia and lymphoma," Lu said. However, he added that it is hard to say at this point if exposure to these chemicals is definitely a risk factor for these cancers.The association between pesticides and cancer risk is not necessarily limited to leukemia and lymphoma, either, Lu said. Pesticide exposure may also drive up the risk of other types of cancers, such as prostate and bladder, but they have not been studied as much, and are more difficult to research because they take longer to develop, he said. If childhood pesticide exposure helped trigger the onset of these other cancers, they might take many years, possibly into adulthood, to manifest.

The fact that the study found an association between only indoor use of insecticides and increased rates of cancer makes sense, Lu said, because there is less fresh air indoors to dilute the chemicals. And insecticides could be particularly damaging because they are sprayed around the home, whereas herbicides are usually used only around plants, he said. Children can be exposed to pesticides by breathing them in or eating them, Lu said. Chemical residues linger on surfaces where children play or spend time, and they may get them on their hands and put their hands in their mouths. In general, children younger than age 12 appear to be most vulnerable to the possible cancer-causing effects of pesticides.

Other research has suggested a link between parents who are exposed to high levels to pesticides at work, such as through farming, and increased rates of cancers such as leukemia and lymphoma, both in these adults and their children.....In the case of how insecticides could be causing cancer, it may be that the same ingredients that kill insects could be causing genetic mutations in blood cells that lead to leukemia and lymphoma, Lu said.

In the meantime, parents can take precautions to reduce their exposure to pesticides. The most effective way is to prevent pests in the first place, by cleaning up old food, and repairing cracks and crevices through which insects can enter, Lu said.If the pests have already taken over, try non-chemical means first to wipe them out, such as using diatomaceous earth, a powder made from fossilized earth that dries out insect exoskeletons, Lu said. If parents feel they have to use chemicals, opt for bait strips rather than sprays that get everywhere, Lu said.

Some of the studies that Lu and his colleagues included in their analysis suggest that rates of cancer were highest among children who were exposed in the womb and among those whose parents were exposed before they were conceived. "Women who are pregnant or intend to become pregnant can avoid home insecticide application," said Roberts of the Medical University of South Carolina.

Although it is too soon to say unequivocally whether pesticide exposure increases the risk of childhood cancers, there is stronger evidence connecting these chemicals with neurological consequences, such as lower IQ and attention deficit hyperactivity disorder, Karr said.

Pesticide exposure has also been linked to headaches, nausea, skin irritation and other symptoms, according to an American Academy of Pediatrics policy statement on children's exposure to pesticides, which Roberts and Karr wrote. A study to be published in the October issue of Pediatrics along with Lu's research raises the possibility that high doses of pesticide may even lead to sudden infant death. A post-mortem analysis by researchers in Italy of a 7-month-old girl who had died in her sleep revealed high levels of a pesticide called DBNP in the brain tissue. The girl may have inhaled the chemical after her father sprayed insecticide around the house to kill flies in the two weeks before her death. "This single incident would be reflective of acute toxicity. Pesticides play a role in acute and chronic health problems depending on the level of exposure," Lu said.

From Medical Xpress;  Home pesticide use tied to child cancer risk

Children exposed to insecticides at home may have a slightly increased risk of developing leukemia or lymphoma, a new review finds.The analysis, of 16 studies done since the 1990s, found that children exposed to indoor insecticides had an elevated risk of developing the blood cancers. There was also a weaker link between exposure to weed killers and the risk of leukemia....."Despite the questions, Lu said he thinks it's wise to act now, by limiting babies' and children's exposure to chemical pesticides—especially the indoor insect killers that this study linked to leukemia and lymphoma.

Overall, children who'd been exposed to any indoor insecticides were 43 percent to 47 percent more likely to have leukemia or lymphoma, the findings showed. Outdoor insecticides were not linked to the cancers.Kids exposed to weed killers, meanwhile, had a 26 percent higher risk of leukemia, the investigators found.