A study released by the University of Michigan (UM) Thursday found that chemical naled currently used to ward off mosquitoes carrying the Zika and chlorpyrifos, an insecticide, can produce negative impact on the motor function of infants.
Researchers at the UM School of Public Health and UM Center for Human Growth and Development came to this conclusion and posted it on the UM website after testing children in China.
The study found the top 25 percent of infants that are exposed to chemical valed via their mothers during the pregnancy have their fine moto skills three to four percent lower at 9 months than those in the lowest 25 percent of exposure.
Infants exposed to chlorpyrifos scored two to seven percent lower on a range of key gross and fine motor skills.
Girls are more sensitive to the negative effects of the chemicals than boys, the study found.
In the children studied, naled affected fine motor skills or the small movements of hands, fingers, face, mouth and feet, while chlorpyrifos was associated with lower scores for both large movements of arms and legs and fine motor skills.
The UM researchers examined the umbilical cord blood of some 240 mothers, looking for exposure to 30 different organophosphate insecticides, five of which showed up in at least 10 percent of the samples. In addition to naled and chlorpyrifos, researchers also found methamidophos, trichlorfon and phorate.
The researchers then followed the development of the babies using the well-known Peabody Developmental Motor Skill Assessment at 6 weeks and 9 months. No deficits were noted at 6 weeks.
Naled is one of the chemicals being used in several U.S. states to combat the mosquito that transmits Zika, while Chlorpyrifos has been used on vegetables, fruit and other crops to control pests since the 1960s.
China is the world's largest user of pesticides. As exposure to the chemicals is a worldwide concern, the concern is especially serious in China, the study said.