Pregnant women who use a lot of household chemical products are more likely to have babies with persistent wheezing, new research reports.

The products included bleach, disinfectant, air fresheners, aerosols, carpet cleaners and pesticides.

Children with wheezing are more at risk of eventually developing asthma, explained study author Dr. Andrea Sherriff at the University of Bristol in the UK.

Moreover, “persistent wheezing stops the child from living a normal life - exercising, going to school,” she told AMN Health. This “may make them susceptible to other conditions, such as obesity.”

Although the study did not measure how much exposure to household chemicals is safe for pregnant women, Sherriff recommended that they should “be sensible” with chemicals, and follow the product’s instructions, particularly with regards to ventilation.

Previous research has found that people who are heavily exposed to household products are more likely to develop symptoms of asthma. Of all professions, cleaners have one of the highest risks of developing the disease.

To see if prenatal exposure to these chemicals also increases the risk of breathing problems, Sherriff and her team asked the mothers of 7019 children about the chemicals they were exposed to while pregnant, and how often their children wheezed from birth to age 42 months. The women completed surveys while pregnant, and periodically after the child was born.

Slightly more than 6 percent of the children showed signs of persistent wheezing.

The children whose mothers used the most chemicals were more than twice as likely to persistently wheeze than those whose mothers used the least chemicals, the authors report in the journal Thorax.

Sherriff explained that experts suspect that chemicals may affect infants’ breathing by irritating their airways and lungs. She added that mothers who use a lot of chemicals during pregnancy will likely do the same thing once the babies are born, so it’s difficult to say whether a baby’s wheezing comes from exposures before or after birth.

Alternatively, she suggested that infants who are in an overly clean environment may not be exposed to the bacteria and germs that help us build healthy immune systems.

“If we have immune systems which don’t work well, then we are more likely to become allergic to things in our environment, and possibly wheeze as a result,” Sherriff said.

SOURCE: Thorax, January 2005.